Journal of Holistic Performance | ISSN: 2463-7238 | Published: 4 May 2018
Cliff J. d C. Harvey,1 Grant M. Schofield,1 Micalla Williden,1
Background. Very-low-carbohydrate ketogenic diets (VLCKDs) promote benefits for a range of health conditions. However, there is little research elucidating the ‘lived experience’ of individuals undertaking these diets, and the effects of keto-induction, during adaptation to these diets.
Objective. This study aimed to evaluate the subjective experiences of people following a very low carbohydrate, ketogenic diet.
Design. This paper describes the qualitative experiences of twenty-eight non-obese, non-diabetic participants, (2 males, 26 females: age ± SD: 35 ± 4 y) in a randomised controlled trial to test the effects of medium chain triglyceride (MCT) supplementation in a VLCKD on time to nutritional ketosis (NK), symptoms of keto-induction, and mood. The experience provided by the diet was rated by a free-form daily diary entry and post-study focus group. Diary entries and focus group transcription were coded inductively and grouped into common themes.
Results. Twenty-three participants completed the 3-week study. Physical effects accounted for over 28% of references. Other results were categorised as; mood, energy and cognition (23%), satiety and hunger (16%), cravings and temptation (11%), and sleep (8%). Overall, 49% of references were classified as ‘positive’ with 8% neutral, and 43% negative. Positive impressions were higher after participants had achieved nutritional ketosis and negative impressions higher during keto-induction. Negative impressions, both concerning physical symptoms and feelings of mood and well-being, tended towards improvement over the course of the study, and positive impressions improved. However, there was a large variation in responses, and several respondents reported adverse effects throughout the study.
Conclusion. Despite challenges, especially gastrointestinal effects, the overall perception of the diet was positive, and it provided benefits for wellbeing, mood, sleep, and sugar cravings which tended towards improvement over the course of the study. Negative experiences decreased as participants adapted to the VLCKD. Most participants continued post-study, using a lower-carbohydrate diet, due to these perceived benefits. Our findings suggest that the experience of a VLCKD is positive but variable. Further research on individual tolerance and response to low carbohydrate diets is warranted.
Low-carbohydrate, high-fat (LCHF) and very low-carbohydrate ketogenic diets (VLCKDs) offer specific benefits for health conditions ranging from neurological disorders, cancer, obesity, diabetes and other conditions on the spectrum of metabolic syndrome. (1-11) Adaptation to a ketogenic diet (keto-adaptation) facilitates the improved use of lipids for fuel and offers the potential for cognitive and physical performance enhancement. Thus, they are becoming increasingly popular for mainstream and athletic use for a range of outcomes including weight-loss and maintenance, (12) improved satiety and a reduction in hunger. (13-15) Ketogenic diets result in ‘nutritional ketosis’ (NK) that is distinct from pathological ketoses, such as diabetic ketoacidosis (DKA), (16, 17) the condition characterised by a triad of hyperglycaemia (blood glucose > 11 mmol.L-1), increased total body ketone concentration of > 3 mmol.L-1,18 and resultant metabolic acidosis. (17) VLCKDs typically result in beta-hydroxybutyrate (BOHB) levels of ≥ 0.5 mmol.L-1 19 and <5 mmol.L-1 without hyperglycaemia, and this level has been used previously as indicative of entry into NK. (20)
Adaptation from a standard, higher-carbohydrate diet, to a VLCKD, and the induction of ketosis (keto-induction) can cause various unpleasant symptoms, for several days. (21) These symptoms can be referred to, in common parlance, as ‘keto-flu’ but are not well elucidated in the scientific literature. For example, a Google search returns over 22,000 results for the term “keto-flu” but the same term searched in MEDLINE Complete, CINAHL Complete, Alt HealthWatch, Food Science Source, SPORTDiscuss with Full Text, Psychology, and the EBSCO Behavioural Sciences Collection returns no results. Symptoms of keto-induction are predominantly constipation, headache, halitosis, muscle cramps, diarrhoea, and general weakness and rash. (22) These symptoms result from increased natriuresis, kaliuresis, and diuresis in response to lowered insulin levels, transient reductions in glucose provision to the brain, and constipation resulting from reduced food volume or reduced fibre intake. (23-26) These factors and resultant adverse effects are typically limited to the first 1-4 days of a ketogenic diet. (23, 27)
Yancy and colleagues noted an 8% drop out rate due to difficulties adhering to an LCHF diet, with a further 5% withdrawing from their study due to adverse effects. (22) High attrition rates due to tolerability and gastrointestinal side effects also occur in childhood epilepsy research.3 However, few studies have specifically looked at the human experience of a ketogenic diet and symptoms of keto-induction, keto-adaptation and personal reflections on the challenges and opportunities of the diet. Studies have noted common adverse physical effects, such as dehydration and gastrointestinal (GI) disturbances. (28, 29) However, these studies did not investigate the qualitative, ‘lived experience’ of participants undertaking a VLCKD. The experience of any dietary intervention is likely to affect compliance and adherence, and in the absence of significant differences between outcomes from different diets, an improved human experience while following a diet, could provide for relative superiority due to ease, comfort and enjoyment.
The overarching aim of this study was to evaluate broad themes of experience within a ketogenic diet and to provide ‘snapshots’ of individual experiences of a ketogenic diet. This paper aims to help clinicians understand better the challenges and opportunities presented by the diet and to help inform further research that may be of use to those following ketogenic diets.
This research reports on qualitative data collected within a randomised controlled trial comparing the use of medium chain triglycerides (MCT) to long-chain triglycerides in a classic (4:1 lipid to non-lipid ratio) ketogenic diet. Daily diary entries were recorded in an online questionnaire using Google Forms online software, and a post-study focus group was facilitated by one of the research team and recorded and transcribed by the primary researcher. The research was conducted in accordance with AUT ethical guidelines. Ethics approval was provided by the AUT University ethics committee, approval number 15/317. All participants were briefed twice on the intervention and study and gave written informed consent.
Participants and setting
Twenty-eight participants (2 males, 26 females: age ± SD: 35 ± 4 y) (table 1) were recruited between the 18th and 19th of October 2015 by a ‘snowball method’ (30) from the researchers’ social media networks, with sharing encouraged to facilitate a ‘viral’ spread of recruitment and a broad demographic range of participants. All participants gave written, informed consent to participate in a randomised, double-blinded, placebo-controlled study. Participants were required to be non-obese (< 30 BMI), not diagnosed as diabetic, not currently nor previously following a ketogenic diet and not a client of any of the researchers in clinical practice.
Table 1. Demographic characteristics of participants
The study took place between the 2nd and 21st of November 2015. Collection of data and analysis was performed at AUT Human Potential Centre, Auckland, New Zealand. (Figure 1.) The trial was registered by the Australia New Zealand Clinical Trial Registry. ACTRN12616001099415.
Figure 1. Participant flow diagram
Participants were prescribed a ketogenic diet plan with a 4:1 lipid to non-lipid ratio. Males were allocated a diet containing 2200 kcal.day-1 and females 1800 kcal.day-1 each equating to 80% calories from fat (including supplemental oils), 13 to 17% from protein and 3 to 6% from carbohydrate. Minor differences in carbohydrate and protein were due to the use of protein intake of 1.4 g.kg-1 (population means for male and female respectively) bm.day-1, consistent with International Society of Sports Nutrition (ISSN) guidelines for optimal protein intake for performance.31 Participants were randomised to receive either an MCT supplement containing 65% caprylic acid (C:8) and 35% capric acid (Amtrade NZ limited) as triglyceride or a long chain triglyceride (sunflower) oil (Home Brand), 30 ml, three times per day, for 20 days. Additionally, participants were provided with two introductory workshops to elucidate the dietary plan and its use. This paper reports the overall, qualitative impressions of a ketogenic diet across the intervention. Diary entries and focus group transcription were coded inductively and grouped into common themes. Twenty-three participants completed the study. Two withdrew from the MCT group (illness and gastrointestinal discomfort) and three (one due to extreme hunger, one unreported and a third due to lightheadedness and inability to concentrate) from the LCT group. These results were omitted from this analysis. Participants were instructed to contact the primary and tertiary researchers for any assistance during the study duration. CH is a registered clinical nutritionist with the New Zealand Clinical Nutrition Association, and MW is a registered nutritionist with the Nutrition Society of New Zealand.
Participants entered daily diary entries into an online questionnaire in addition to the measures taken for the RCT above, namely: blood glucose, beta-hydroxybutyrate, Profile of Mood States (POMS), and a ketogenic diet symptom questionnaire developed by the primary researcher (C.H.) based on commonly reported symptoms resulting from keto-induction. These quantitative measures will be reported in a separate paper.
The questionnaire asked the participants to respond to the open-ended, free-form question: “Please tell us about the experience of this diet. Describe in your own words anything that you may have felt or experienced (in the last 24 hours) because of this process”. Additionally, an informal, semi-structured, post-study focus group was conducted. Questions posed in the focus group were also open-ended to facilitate ongoing discussion, e.g. “How did you feel while following the diet?”, “How did the diet differ from your normal diet?”, “Why did you enjoy, or not enjoy, the diet you were on?”, “What effects, if any, did you notice while on the diet?”
Diary entries and focus-group transcriptions were coded using an inductive approach by the lead researcher, with ‘triangulation’ (checking and confirmation) provided by the secondary and tertiary researchers to ensure robustness and validity of the themes and codes identified. In total 458 diary entries were submitted by the participants along with the post-study focus group. 830 references were extracted from the diaries and transcription. Physical effects accounted for over 28% of references. Other results were categorised as; mood, energy and cognition (23%), satiety and hunger (16%), cravings and temptation (11%), and sleep (8%). Additionally, it was noted when participants directly stated that they were ‘feeling good’ and references related to behavioural change were noted to clarify the themes.
Overall, 49% of references were classified as ‘positive’ with 8% neutral, and 43% negative. Positive impressions were higher after participants had achieved NK and negative impressions higher during keto-induction. (Figure 2.) Adverse effects overall, both concerning physical symptoms and feelings of mood and well-being, tended to improve over the course of the study, and conversely, positive impressions improved. However, it was noted that there was a large variation in responses and several respondents reported adverse effects throughout the study.
(Figure 2. Percent of experiences classified as positive or negative during keto-induction, nutritional ketosis, and over the course of the study
Physical effects accounted for the largest category of reported responses. Gastrointestinal (GI) disturbances accounted for most adverse effects noted while on the diet. These included diarrhoea (the most commonly reported adverse effect), stomach cramps and constipation. Interestingly these GI effects were noted almost exclusively in the intervention group (those taking MCT oil). These symptoms, especially cramping and diarrhoea, are known effects associated with MCT supplementation. Ivy and colleagues have previously observed that 100% of participants in their study experienced gastric distress (cramping and diarrhoea) with dosages of 50 and 60 g MCT, with small effects at 30 g.32 Less frequently reported were headaches, muscular cramps and physical weakness and one participant experienced a nosebleed. One participant considered pulling out of the study (unbeknownst to the researchers and revealed in the post-study focus group) due to extreme symptoms; “I found it was very hard. Everything went wrong; headaches, shakes, dizzy, up all night just trying to get fluids in. “I honestly yes, almost quit because I felt it was dangerous.” She sought medical advice and was provided with an electrolyte solution that caused the symptoms to abate. Interestingly, this participant stated that the ‘hardship’ of having these extreme symptoms and overcoming them, provided a reason to continue with the diet during, and after the study; “Probably because it ended [the physical symptoms], and after the ending, I had a recipe for success.”
Some physical weakness was noted in association with exercise, but not concomitantly with lowered energy or mental cognition or mood. Instead, mood, energy, and cognition were improved (when compared to the perception of mood before the intervention), even though muscular weakness was present during exercise. Physical effects, in some cases, affected wellbeing; “Feeling low in energy, headachy, stomach pain after meals is not encouraging me to be overactive and isn't making [me] feel very happy.” Interestingly, one participant’s asthma symptoms disappeared completely on the diet; “Asthma completely disappeared too.”
Mood, energy, and cognition
Mood, energy, and cognition typically improved over the course of the diet. However, there were adverse effects on these at the beginning of the study. This mood and energy suppression is likely to be related to the lowered provision of fuel (especially glucose) during this period, and other factors (such as electrolyte disturbance).23-26 “I found that just at the start was the hardest part” “but then once I was [in ketosis] I was pretty fine.”
Poor energy (fatigue and tiredness) were commonly reported in the early stages of the diet, when participants, for example, “felt lightheaded” “quite low in energy”, “difficulty focusing and concentrating”. Moreover, for some, the reduction in energy was profound; “Tired and wondering how on earth I’m going to do this for 20 days”. However, for this respondent, and others, reported energy and mood did improve over the course of the study period. Conversely, some though suffered poor energy up until the end of the 20-day study; “bit lightheaded and tired, so everything seems to take a little more effort. Quite looking forward to finishing diet”, and others made no mention of poor energy at all, instead, only stable or improved energy.
Changes in energy patterns were noted, with either reduced or improved energy in the morning; or a ‘crash’ in the evening. “For most of the day, I felt great, at the end of the day I really seemed to crash.” Over the course of the study, energy mostly stabilised or improved for those reporting poor energy early in the study, along with improved or enhanced mental focus and clarity, e.g. “really noticing a steady energy level especially at night when I am not exhausted going to bed. I just know I need to sleep but not shattered and 'over it' which is how I used to feel” and “Feeling very even in my moods (as in no real highs or lows and more 'mindful')”.
Irritability was noted by several participants, predominantly in the early days of the study, and characterised by comments such as “having a short fuse” and “tired with a short fuse”. This irritability was also noted as a feeling of being ‘wired,’ i.e. “[I] felt bloated, wired and tired!” and was not necessarily related to increased energy, but instead, with fatigue. It is possible that this irritability and ‘wired’ feeling was related to increased sympathetic nervous system activity associated with carbohydrate withdrawal and the early keto-induction phase. This enhanced sympathetic nervous system activation, and increased epinephrine, norepinephrine, and cortisol has been observed in the early stages of carbohydrate-restricted diets and provides for the increased provision of glucose to preserve work capacity. (33-35)
Those who participated in exercise noted reduced energy in response to exercise, despite daily energy levels being stable or improved (in contrast to habitual peaks and troughs); “Got an hour's bike ride in and felt rooted from the start. Energy levels still stable but just low”. For two participants this was also exacerbated by mistakenly not taking the prescribed amount of supplemental oil. Omitting or taking the incorrect dosage of the supplemental oils, albeit accidentally, is likely to have affected energy levels significantly, as the major provider of calories on a ketogenic diet are lipids.
Despite lower than normal perceived energy during-exercise earlier in the study, energy seemed to improve for participants over the duration of the study. For example, a participant noted on Day 3; “Hard CrossFit session but no energy,” yet by Day 18, despite being tired he did a “Hard CrossFit session” that he had “heaps of energy for!” Others shifted to a higher state of energy very quickly; “Feeling really good, energy levels are great!” (Day 4).
A potential confounding influence on energy levels was that calories were uniform based on a population- and age-appropriate eucaloric allocation of 2200 kcal for males and 1800 kcal for females. Thus, exercise would have provided a calorie deficit to hard-training participants. Training and exercise were not controlled in this free-living study.
It was also common for energy, mood and clarity to be improved even in the presence of negative physical effects such as diarrhoea, nausea and GI distress, and in the absence of quality sleep. “I must have got about 4 good night sleeps over the whole thing but the really weird thing was that during the day like as soon as I ate breakfast my energy levels came up and it was like I had a super power….”
Overall there seemed to be a general improvement in energy over the course of the study and a tendency towards improvements in ‘stability’ of energy following the VLCKD. While during-exercise energy did also improve over the course of the study, our impression was that this was reduced overall in relation to the diet.
Satiety and hunger
Satiety was drastically improved for most participants by the ketogenic diet. Ketogenic diets improve satiety, reduce hunger, and reduce the desire to eat. (19, 36) Several participants were surprised at the volume of food, and especially vegetables, in the plan; “Food portions [are] actually more than I would normally eat so, pretty bloated after lunch” and “veggie portions are just too big”. The vegetable portions recommended in the plan were approximately three cups with at least two meals per day to ensure that participants (who were not eating fruit due to the carbohydrate-restricted nature of the VLCKD) were consuming more than the recommended 5+ per day vegetable and fruit recommendation, in accordance with dietary guidelines for health. The difficulty of consuming this amount speaks to a common difficulty in dietary planning in general—compliance with vegetable and other ‘nutrient-dense’ (fruit, berry) food intake recommendations. For example, the New Zealand Adult Nutrition Survey of 2009 showed that many New Zealanders fail to eat the recommended servings of vegetables and fruits, and fail to consume recommended amounts of several vitamins and minerals from diet alone. (37)
This finding provides a hypothesis for vegetables as a ‘crowding’ food type, providing improved satiety and reducing the desire, within a meal, for other foods (such as optional ‘fuel’ foods—particularly sugars and starches). Interestingly, the absence of carbohydrate foods was perceived by some as a challenge not matched by how they felt. For instance, “I was concerned at the amount of food and being hungry, but I was pleasantly surprised that I felt full after each meal for many hours.”
Different portion sizes, in comparison to a habitual diet, appeared to be quite challenging. This was particularly evident in the morning when satiety was increased; “Finding it hard to eat so much at breakfast,” “Feeling much less hungry, couldn’t finish breakfast!” Sometimes this was accompanied by increased afternoon hunger; “extremely hungry after 3 pm” despite improved morning satiety. Feelings of fullness were sometimes associated with a lack of interest in food, characterised by comments such as “disinterested in food” and “no appetite.”
The change in diet itself also caused some ‘confusion’ for participants in their perception of hunger. Several participants previously ate more and snacked more frequently. Thus, they wondered whether they did, in fact, need so much food or whether they were simply habituated to it. “It’s difficult to tell if it’s ‘real’ hunger (I don’t think so) or just ‘habit hunger.” Because of this, some participants began to alter the diet – for example by consuming a smaller breakfast due to an inability to eat all the food prescribed.
A change was observed in response to snacking behaviours; “Normally I will be hungry for each meal especially when waking up in the morning or going longer than usual without a meal, and now I am finding this is not so much the case.” For instance, a participant noted on the first day of the study that it was a “shock” not snacking, but the following day noted, “[I] am finding the not-snacking’ easier than anticipated” and by the end of the study “Not so hungry before meals, not starving or constantly thinking about my next meal.” Others noted similar surprise at the elimination of the need for snacking, e.g. “I was surprised at how well I coped given the lack of snacks I usually have” and the ability to go for much longer periods than used to without needing to eat meals or snack; “I'm used to eating every 3 hours” I went from 12.30 pm to 6.30 pm without eating—unheard of!!” Occasionally, hunger led to cravings and non-compliance with the diet, i.e. “Felt hungry at times and couldn’t resist some bread and a few hot chips.”
The supplemental oils prescribed for the study appeared to improve satiety and provide a sense of ‘fullness.' So, in addition to accountability provided by being involved in a dietary study, the satiating effect of the oils was a factor contributing to compliance. “I think for me it wasn’t that I was following a strict regime, it was just that the oil made me feel so full”. The oils, however, were associated with physical symptoms of nausea and GI effects (as noted earlier).
Overall responses and effects of the diet were very positive; “I like that it’s a good amount of calories and I’m not hungry”, “I have felt full most of the time and have enjoyed eating more fat and protein”, “I definitely don’t feel hungry during the day on this diet”.
In general, satiety was improved, with comments of ‘fullness’ common; “I feel full most of the time” and “I have to force myself to eat as not feeling hunger”. Improved satiety positively affected cravings “I always feel full and no cravings”, “I didn't crave the pizza or feel like I was missing out”, “I feel so surprised at how full I’ve been feeling on this program.”
Cravings and temptation
It has previously been demonstrated that low-carbohydrate diets reduce cravings and desire for sugar and starches. (38) We noted a general improvement in sugar cravings in the study. For example, a comment from Day 1; “craving sugar as I have a major sweet tooth” but by Day 7 the same participant noted; “Feeling great, no sugar cravings.” Likewise, other comments indicated the reduced craving for sugar “Sugar/junk food cravings are seriously diminished. First time ever!” and “Not craving much at all” Not craving carbs, sugar”, “not fantasising about custard squares!” Satiety, possibly enhanced by the supplemental oils, reduced sugar cravings; “Have noticed that sugar cravings come back with a vengeance if not having enough fat with each meal.” Participants who reported a tendency to have sugar cravings (or the “sugar demon” as one participant put it) tended to agree that if you have a little, you cannot help but have more; “when you have carbs they make you crave more.” “I feel so bad [when eating sugar], and the only thing that would make me feel better is to have more.” Ingesting carbohydrate (especially sugar) improves mood in people who experience sugar cravings. (39) In these diets, carbohydrates are quite literally ‘off the table’ and cannot continue to drive the positive feedback loop of craving more sugar. Evidence links dopamine release in the mid-brain to the pathophysiology of psychosis, addiction and reward. Repeated ingestion of refined carbohydrate in a ‘normal’ western-style diet, stimulates the same dopaminergic pathway. (40)
Other comments indicated a behavioural tendency towards a mixture of moderation and abstinence, e.g. “I would like to have one day where I can eat anything I like, but I am stricter on the other days like you know having that day to look forward to where I can eat anything.” Others lamented the ability not to be able to moderate food intake; “I just wish I had the ‘one bite ability,’ you know, just to taste a cookie rather than a whole pack…”
Although we noted a strong, general improvement in reported sugar cravings, over the course of the study, we noted an increase in the desire for, but importantly, not craving for carbohydrates (starches). This pattern appeared to be related to a desire to return to more ‘normal’ dietary patterns.
Typically, during the study, cravings were resisted, when previously they may have been succumbed to; “Really want carbs … bread and butter never looked so good! Have refrained”, “desperately wanted to just eat rubbish. Pure psychological warfare. Funny. Mostly resisted”
Non-compliance with the diet was also associated with negative effects. “Eating off plan yesterday left me with a huge food hangover”, and there was a reluctance to ‘give in’ to cravings, especially where there were high perceived rewards from the diet (especially weight loss). “Craving sugar today, but not wanting to go back to normal eating as I don’t want to put the weight I’ve lost back on”.
Cravings and temptation that did arise during the study did not appear to result from reduced satiety or increased hunger. “[I] was tempted with my son’s porridge today but amazed that I’m stronger than my sugar cravings and they’re going too.”
Additionally, some participants became bored with the compendium of foods available; “Getting a bit bored with the food” and “Sick to death of meat and eggs.”
Despite social situations providing a challenge, the diet, due to its restricted nature, enabled easier choices, especially at restaurants. “I felt like restaurants were fine as you can order fish or meat and then get two sides of vegetables”. This suggests that nutrition education (‘what’ to eat) and enabling strong, self-determined decision, is critical to the nutrition counselling process, rather than a simple dietary prescription.
Overall, references related to sleep indicated improved sleep quality while following the VLCKD. improvement; “Sleeping really well and feeling great.” “Great, solid eight hours sleep.” “I’m also falling asleep better, rather than tossing and turning how I used to.” Improvements in sleep quality have been observed in children with epilepsy following a ketogenic diet, (41) and ketogenic diets improve the GABA-glutamate ratio, providing a plausible explanation for greater relaxation and improved sleep. (42)
Difficulty getting to sleep was occasionally noted by some, however. This was often in association with a ‘racing heart’ indicative of a high stress-response such as “I would wake up at about 2 am, so getting to sleep my muscles and everything felt quite restless, like jittery, and then I would get to sleep” or “Had difficulty getting to sleep and felt like I had a racing heart”. As mentioned earlier, there are sympathetic nervous system effects during the early adaptation to a ketogenic diet, that might increase one’s ‘stress response’. One participant had extreme difficulties sleeping, noting early waking, trouble getting to sleep and sugar cravings; “finding that I am not sleeping well at all - waking often and too early...so I am getting tired only because I feel like I am not getting quality sleep”, “really tired today - not sleeping well at all...huge sugar cravings - suspect due to tiredness...had to eat nuts to manage my way through”. Interestingly, despite a real challenge with sleep, the participant felt good, and had improved mental clarity and focus; “really struggling with sleep...waking incredibly early and having trouble getting off to sleep at night. Otherwise feel good!”, “tired yesterday from terrible sleep - still great mental clarity though,” “Not sleeping well at all. Totally exhausted today. Even had a day sleep which is not like me at all. Still mental clarity though”.
Post-study reflections and intended changes.
Participants in the post-study focus group all stated that they desired to continue on a reduced carbohydrate diet. Most commonly, they desired to continue to experience improved energy or cognition, reduced cravings and improved satiety, and weight loss. This was typified by statements such as; “I really enjoyed it. I lost weight; my skin cleared” …emotionally it was probably the most even-keeled I have felt in a really long time” and “I really liked the fact that I was not hungry, and I also wasn’t emotional eating either, and I liked the kind of rigidity of the eating plan.” Moreover, this appeared to cause a ‘shift’ in habits and a desire to educate oneself about lower-carbohydrate food options; “Because I felt so good, I felt like I need to carry this on, so I branched out and read a lot.”
Our impression from the post-study focus group was that most participants were likely to continue to follow some variation of a carbohydrate-restricted nutrition plan. For example, “I have kind of stuck with it somewhat” I’m certainly doing a modified version”, but without the heavy use of supplemental oil, choosing instead whole-food dietary fats and perhaps adding in some whole food, nutrient-dense carbohydrate types (such as kumara (sweet potato) and yams); “I found it hard that I couldn’t have baked kumara so I was craving it when I would usually never crave that and I was kind of like ‘give me the carbs!!’ I feel long term a modified version of that plan would be really good.”
Even when returning to a diet closer to habitual, higher-carbohydrate eating (albeit still lower in carbohydrate than previously consumed) there was a tendency to be mindful of carbohydrate portion size; “I’m still eating bread and rice but maybe not as much”.
Greater attention to carbohydrate quantities in food could provide positive, long-term health benefits, as reduced carbohydrate diets are likely to be more effective for early weight loss for those obese and insulin resistant than comparable low-fat diets. (43-46) Insulin resistant people also adhere more easily to low-carbohydrate diets, and there is no detriment to adherence for those insulin sensitive. (47)
Anecdotally, our clinical observations have indicated that cost can be perceived as a prohibitive factor to the use of ketogenic and lower-carbohydrate diets. Although this was not a stated outcome of our study, the relative costs of the diet vs habitual eating were mentioned in the post-study focus group. Those that didn’t habitually eat meat and other high-protein, higher-fat, lower-carbohydrate foods found the diet more cost-prohibitive, e.g. “[Cost was] Maybe a bit more because I do not usually cook or buy meat much” and “I was eating more meat so maybe a little bit more costly”. Whereas those that habitually ate more meat and processed and refined foods found it cheaper than their usual diet; “I thought it was cheap, especially as the protein/meat portions on a ketogenic diet are restricted.” “And [[I’m] not eating as much meat as usual”. A lower overall cost was also evident for those with a greater tendency to snack, compared to non-snackers; “I feel like because I am [usually] eating so many snacks usually I found it actually quite cheap”.
The consensus was that the diet intervention was a worthwhile experience for several reasons. Accountability was a major factor and is perhaps a confounding aspect of any dietary study; “if I wasn’t in the study I would not have persevered”. The accountability provided by the daily ketone readings had the effect of ‘gamifying’ the experience and people, therefore, wanted to comply. “You know with daily readings there was that sort of accountability with it”. However, the ongoing cost (post-study) of the ketone testing strips provided a barrier to the continued use of this tool for accountability; “the sticks ran out just as I finished and so I went to the chemist to buy more and they are $3.15 per stick and for me that was just way too much.”
Being involved in the study and having ‘choice’ taken away was a powerful contributor to compliance; “What I have found is that the choice is actually taken away from you. Instead of thinking I could have one biscuit at home it is actually no gingernuts and you kind of think ‘oh easy’. So, it isn’t really a self-control issue, because when it comes to sugar, I do not have any”.
Self-care was also mentioned as a motivating factor; “another thing that was so great about doing this was that I was doing something for me, instead of doing something for everyone else in the household, I actually had the focus on me and what I was putting into my body and what I was doing for me and other people were sort of supporting me and they were supporting me with it and I really enjoyed that.”
There was also a community aspect to this, both between the participants and within the extended communities of the participants. “People were always asking me what my numbers were, my brother or my mum or at work and you know everyone was quite interested you know how is it going kind of thing”.
There were significant challenges faced by the participants in this study, particularly concerning physical effects. Many of these effects were GI and were mostly limited to the intervention group (taking MCT oil) for which GI effects are a known side effect. However, other side effects and physical symptoms also provided a significant challenge. Despite this, the most serious side-effects were experienced by people who subsequently became advocates for continuing the diet. This typically occurred once the keto-induction period ended, or methods had been found to mitigate the negative symptoms (such as additional electrolytes).
The overall perception of the diet was positive, and the ‘lived experience’ of the diet likewise provided benefits for the overall feeling of wellbeing and mood, along with improved sleep and reduced frequency of sugar and carbohydrate cravings.
Most participants in the focus group stated that they were continuing with some form of modified lower-carbohydrate diet due to the benefits, and this suggests that the ‘lived experience’ of a ketogenic diet overall is positive and that aspects of lower carbohydrate eating are both sustainable and may be preferable to habitual, higher-carbohydrate eating patterns.
Negative experiences diminished as participants adapted to a VLCKD, and so it is unlikely that a ketogenic diet per se causes negative effects. Rather, it is the adaptation to the diet and its differential fuel use, transient increased sympathetic nervous system activity, and most prominently electrolyte imbalance (23-26) that causes these challenges. These effects are minor and limited to the first 1-4 days of a ketogenic diet. (23, 27) More importantly, for some participants, the diet itself provided a near epiphany, in that it offered a dietary option that provided a greater degree of freedom from hunger and cravings, and offered satiety, and enhanced mood and wellbeing.
The results though were highly variable between individuals. Submissions also varied considerably in quantity and depth, and we cannot exclude the possibility that those more enamoured with the dietary approach were also more effusive in their daily diary entries. Likewise, the voluntary post-study focus group was attended by eight people out of the original 28 participants, and this is unlikely to provide a comprehensive view of the effects on the lived psychological, psychosocial and psycho-emotional effects of a VLCKD. Despite this, the available qualitative data indicates that the experience of a ketogenic diet is a positive one.
There were several limitations to this study. Differences in compliance may have resulted from the free-living nature of this study. We did not adjust for exercise and activity, although participants were advised not to change their current exercise habits. Standardised diets (both for male and female) were provided per age- and gender-adjusted average requirements. Thus, those participants that were more active may have experienced the diet differently due to a relative calorie restriction. We also recognise the limitations of our convenience sample arising from the snowball method of recruitment, via our networks on a first-come basis, as this led to an almost entirely female cohort. There may be differences in the lived experience of a ketogenic diet between genders, but to our knowledge, this is not indicated in the literature, and while we do not have any reason to believe that the results would not apply similarly to men, our results should be interpreted conservatively.
We also recognise the limitations of qualitative research methods. While we sought to reduce bias by using an inductive, rather than a deductive approach to thematic identification, and through ‘triangulation’, checking and confirmation of codes by co-researchers, the research and analysis, by its very nature cannot be wholly objective, nor should it be.
The authors would like to humbly submit this work to the wider field of clinical nutrition for what it is, a qualitative appraisal by practitioner-researchers, of the experience of a ketogenic diet.
The lived experience of a ketogenic diet is likely to provide appreciable benefits for some people, but further research to better understand the individual tolerance and response to differing diets is warranted. In addition to this, further research to find methods to indicate clinically appropriate diets for individuals based upon physical, psychological or personality characteristics, either known or yet to be elucidated would provide a valuable tool for practitioners.
Very-Low Carbohydrate, Ketogenic Diet (VLCKD); Medium Chain Triglyceride (MCT); Long Chain Triglyceride (LCT); Nutritional Ketosis (NK); Low Carbohydrate, High Fat (LCHF); Diabetic Ketoacidosis (DKA); Profile of Mood States (POMS); Total Mood Disturbance Score (TMDS); Auckland University of Technology (AUT)
We are grateful to the participants in this study. We also acknowledge the support of our colleagues at the Human Potential Centre, AUT University.
1Human Potential Centre, Auckland University of Technology, Auckland, NZ
Conflict of interest
The authors declare that they have no conflict of interest
CJdCH, GMS, and MW designed research; CJdCH conducted research; CJdCH, GMS, and MW analysed data; CJdCH wrote the paper, with editing assistance from GMS and MW. CJdCH had primary responsibility for final content. All authors read and approved the final manuscript.
All funding was provided by the Human Potential Centre, AUT.
Received: Accepted: Published:
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Exploring the acceptability of, and adherence to a carbohydrate-restricted diet as self-reported by women aged 40-55 years
Journal of Holistic Performance | ISSN: 2463-7238 | Published: 23 January 2018
Julia Claire McPhee1, Caryn Zinn 1, Melody Smith2
Background. It is well recognised that ageing in females is associated with a predilection for weight gain. Women with abdominal obesity are known to be at especially high risk of cardiovascular and metabolic disease, as well as associated poorer overall health outcomes. Many of these metabolic disorders, however, can be alleviated through weight loss.
Methods. This research describes an exploratory study investigating the self-reported acceptance of, and adherence to, a carbohydrate-restricted diet in women aged 40-55 years old. The 8-week weight loss dietary intervention was based on a whole food approach, which was lower in total carbohydrate and higher in dietary fat than mainstream nutrition guidelines. The two primary outcome measures of this research were barriers to and motivators for acceptance of and adherence to this way of eating. The mixed methods approach employed endorsed a multi-level intervention, integrating behaviour change models with both the medium of delivery and required dietary modifications.
Hypothesis. The hypothesis underpinning this study is that a lower carbohydrate, higher fat (LCHF) dietary approach, through its macronutrient profile, has the potential to enhance an individual’s self-reported adherence to behavioural lifestyle modifications required to reduce weight and improve metabolic health outcomes.
Results. Support by family members, in particular, spouses, was a key theme and appeared to act as both a barrier and motivator to adherence. Subsequent themes included satiety or feelings of fullness, being prepared by ensuring suitable food options were readily available, and acceptability of new food options.
Discussion. The findings from this study suggest self-reported adherence to this way of eating was achieved via improved satiety and enhanced social and spousal support. Moreover, results showed that for this population group, the intervention design was appropriate and medium of delivery was effective.
Global overweight and obesity rates have more than doubled in the last three decades, with 1.4 billion adults over the age of 20 years classified as overweight (body mass index [BMI] 25–29.9 kg/m2) or obese (BMI ≥ 30 kg/m2)by the World Health Organisation, (1) in 2008. While it is well-recognised that comparable numbers of females and males are classified as overweight (35% versus 34%, respectively), more women than men are categorised as obese (14% versus 10%, respectively). (2)
Women classified as overweight or obese exhibit higher rates of metabolic irregularities including hypertension, diabetes, and reduced mental health and energy levels than their normal/underweight counterparts. (3) The prevalence of central adiposity and features of metabolic syndrome in many peri-menopausal and menopausal women transpire as a result of a reduction in oestrogen. (4) Fortunately, many of the metabolic disorders attributable to decreased oestrogen levels (exhibited in conditions such as abdominal adiposity, insulin resistance, and dyslipidaemia) can be alleviated through weight loss. Furthermore, it is understood that oestrogen has a modulating effect on the hormone insulin and lipoprotein lipase (LPL; an enzyme responsible for breaking down triglycerides), both of which are recognised as impacting central adiposity. (5) During this period of mid-life weight gain and increased metabolic risk for women, preventing gains in body fat and maintaining healthy weight status is essential. (6)
Traditional “best practice” weight loss dietary treatment (undertaken in both research and practice) is largely based on calorie (or energy) restriction. In general, weight-loss interventions (predominantly based on traditional weight-loss guidelines) are having little impact on either global obesity rates or sustained levels of weight loss at a population level. Furthermore, middle-aged women continue to fare poorly in a life stage in which weight-gain appears unavoidable. As central weight gain with menopause is associated with the development of insulin resistance, (6) there is increasing interest in weight-loss treatment options based on a macronutrient profile that elicits a reduced insulin response. In contrast to traditional “best practice,” an alternative weight loss strategy promoting a model of eating that is lower in carbohydrate than mainstream guidelines (i.e. <45% of total energy, the minimum threshold for carbohydrate), moderate in protein, and higher in fat has been posited as an effective weight-loss option. This strategy recognises that the macronutrient composition of the diet itself may have a positive impact on weight loss due to the interaction between the nutrients themselves and hormonal expression.
While there remains no consensus over the most effective weight-loss strategy, it is recognised that both the traditional low fat and the more contemporary low carbohydrate, high fat (LCHF) dietary strategies are successful in eliciting weight loss at an individual level. (7) However, there is evidence to suggest that LCHF diets can be successful when compared with “best practice” when it comes to improving health outcomes for individuals. Findings across several randomised controlled trials (RCTs) addressing both weight loss and health outcomes show that LCHF diets are at least as effective as low-fat diets in achieving weight loss, and more effective for improving several blood markers, in particular triglycerides and HDL cholesterol, and HbA1C (in diabetics). (8-11) In one such study participants were randomly assigned to one of four dietary regimes. (9) In this study, women assigned to the lowest carbohydrate intake lost more weight and experienced more favourable overall metabolic effects at 12 months. Secondary analyses examined the relationship between insulin resistance and dietary adherence to either a low-fat or low-carbohydrate diet. (12) Findings showed that participants were less likely to adhere to, and lose weight on, a low-fat diet if they were insulin resistant compared to those that were insulin sensitive. The authors stated that while the mechanisms explaining the reasons for this are largely unexplored, participants with insulin resistance may feel less satiated on a low-fat diet and therefore may experience stronger metabolically driven urges to consume more food. These results are compelling as they suggest that insulin resistance status may affect dietary adherence to weight loss diets. This may result in higher rates of recidivism and diminished weight loss success in insulin-resistant participants following low-fat diets. (12)
While weight loss in the short term appears to occur regardless of the type of diet applied, long-term sustainability of weight loss creates a greater challenge. A further strategy that affects adherence to weight loss interventions is the application of Health Behaviour Theory (HBT) in intervention design. (13) A recent study designed to predict weight loss applied four leading health behaviour change theories: Social Cognitive Theory (SCT), Trans-Theoretical Model (TTM), Theory of Planned Behaviour (TPB) and Self Determination Theory (SDT). (14) Weight change was significantly predicted by each of the HBTs analysed. It is well-recognised by health researchers, however, that no theory will be the perfect fit for any single health-based intervention and it has become evident that the use of a mixed methods approach to applying HBT to interventions elicits more favourable outcomes than interventions aimed at one level of behaviour. (15)
Effective weight-loss strategies, targeting priority populations through appropriate media, remain a critical public health priority and warrant ongoing investigation. (16) While attrition rates in weight-loss programmes are known to be high, increased adherence to a programme can lead to successful and sustained weight loss. (17) The aim of this programme is to determine factors affecting women aged 40-55 years in modifying and maintaining dietary behaviours while undertaking an LCHF way of eating for weight-loss purposes.
This was a cross-sectional study investigating the self-reported acceptance of, and adherence to, a diet restricted in carbohydrate in women aged 40-55 years. The intervention itself was called the LCHF Women’s Health Research Programme. The primary outcome measures of this study were barriers to and motivators for acceptance of and adherence to this way of eating. Secondary outcomes included mood state, adherence, satiety levels, and weight loss. During the intervention, weekly questionnaires were distributed to participants, starting at baseline, with the final questionnaire administered at eight weeks (end of intervention). Focus groups were conducted following completion of the intervention. Ethical approval to conduct the study was provided by the host institution (AUTEC reference 13/339, 14th January 2014).
The internet-based intervention comprised an eight-week programme designed to determine factors affecting women aged 40-55 years in modifying dietary behaviours and maintaining those behaviours while undertaking a carbohydrate-restricted way of eating. Participants were not provided with a prescription of calories or macronutrient breakdown, but rather a range of foods that aligned with the LCHF dietary approach. However, it was anticipated that food choices endorsed reflected an overall daily macronutrient profile comprising moderate amounts of protein (approximating mainstream nutrition guidelines of between 15-25% of total energy intake), reduced carbohydrate (approximating <45% of total energy from carbohydrate), and moderate-to-high amounts of fat (remaining calories). This macronutrient profile is considered to be a restricted carbohydrate diet, anticipated to induce weight loss in participants. (18) Food options that were limited included cereals and grains, starchy vegetables and legumes and those endorsed included non-starchy vegetables, some fruit, all meats, eggs, full-fat dairy product, nuts, seeds, and cooking fats (olive oil, coconut oil, butter).
Participants were provided with access to the LCHF Women’s Health Research website, on completion of the baseline questionnaire. Resources appearing on the website included detailed guidelines on food choices within the spectrum of the LCHF wholefood nutrient profile, food lists, and recipes. The website was created as a medium for delivery of information and resources and to act as a platform for communication between the lead author and participants. Resources were designed and delivered to be consistent with findings from an evidence base of research into web-based weight-loss programmes. Furthermore, the web-based nature of the programme delivery allowed for flexibility in time and venue for access to information.
Further information relevant to the target population included: (i) ‘tips and tricks’, (ii) LCHF recipes, (iii) basic eating plans, and (iv) lists outlining foods to include and avoid. Consideration was made to weekly participant data with subsequent posts adapted to reflect themes emerging each week. The resources were designed to provide support at a level that addressed the diversity of participant needs and knowledge and aligned with the current ‘stage of change’.
Participants were eligible to participate if they met the following criteria: (i) were female, (ii) were aged between 40 and 55 years, (iii) had a BMI status of overweight or obese (25 > 36 kg/m2) (1), (iv) were not currently following any prescribed weight-loss programme, (v) were weight-stable (weight had remained steady for the past 6 months), and (vi) were not already consuming a low carbohydrate diet.
An electronic poster advertising the study was sent via email through Auckland University of Technology (Auckland, NZ) university networks between February 2014 and March 2014. Screening for eligible participants was accomplished through self-reported measures of weight, height, and a 3-day food diary to assess dietary eligibility.
Questionnaire and scales used
Questionnaires were administered using Question Pro online format. Weekly questionnaires included a Profile of Mood States Questionnaire Short Form (POMS SF), (19) a Hunger/Fullness Scale, and a self-rated percentage sliding-scale score (ranging between 1 and 100) of adherence to the LCHF dietary regime supported with a food frequency questionnaire. Participants were also asked to submit self-reported body weight on a weekly basis. Participants received weekly questionnaires each Sunday afternoon through the eight-week study period and asked to complete these at a similar time each week. Participants were advised to weigh themselves at the same time each week; ideally in the morning, and prior to dressing.
Profile of Mood States
The POMS SF is a comprehensive assessment of transient and fluctuating moods, (19, 20) and was chosen to quantify any stress-response to the diet. The POMS SF questionnaire provides a measure of, (i) the tension/anxiety, (ii) depression, (iii) anger, (iv) vigour, (v) fatigue, and (vi) confusion, levels of the participant. Additional mood items included in the POMS SF questionnaire contribute to each of the key constructs. Individual mood items in the POMS SF were rated on a 5-point scale as follows: 0 = “not at all,” 1 = “a little,” 2 = “moderately,” 3 = “quite a bit,” and 4 = “extremely.” This measure allows for assessment of fluctuating emotions and can aid in the effective evaluation of patterns of mood states within an individual. Individual moods scores for the five key constructs were calculated weekly for each participant and for the total mood disturbance score (TMDS). Negative mood states comprise constructs: (i) tension, (ii) depression, (iii) anger, (iv) fatigue, and (v) confusion. TMDS was calculated by adding the five negative mood states together and subtracting the positive mood state, vigour. (20) Total negative moods scores (TNMS) were calculated by adding the sum of average negative moods states. TMDS, TNMS, and vigour data were presented as an average weekly score. Data were presented as an average across participants from baseline to programme completion.
Perceived adherence to the LCHF diet by participants was monitored through a percentage scale with the aid of a food frequency questionnaire. The scale was presented in the questionnaire as a sliding scale from 0 to 100%, with 0% representing no adherence and 100% representative of maximum adherence. An added suite of questions operated as a prompt for participants as to their adherence to the diet, asking them to note the number of occasions over the last week they had consumed a range of high carbohydrate foods that are not recommended on the LCHF diet. These foods included bread, pasta, rice, cereals, cakes, and sweets. Food frequency questions were based on a modified version of the ‘Dietary Habits’ section of the ‘2008/2009 NZ Adult Nutrition Survey’. (21) Response options were adapted to correspond to the weekly (seven-day) questionnaire distribution.
Participants provided weekly self-reported weight status. While weight change over the study period was not statistically assessed, weight loss is a factor contributing to both adherence to weight-loss strategies, and maintenance of weight loss. (22) For the purpose of this study, weight was not used as a primary variable but as a tool to indicate adherence and generate discussion in focus groups.
Groups were classified by participant self-reported adherence (low, medium, high adherence, using average self-reported adherence) to the LCHF food guidelines over the eight-week study period. While focus groups were based on the three adherence levels, if a participant was unable to attend the appropriate group for their adherence level, they were scheduled for the next convenient group. All weight-loss data are presented as a percentage weight loss to ensure standardisation in the variable across all participants
All quantitative data were analysed and presented using descriptive statistics, allowing indicative patterns to emerge. (23) Data is presented in most cases as group findings. Probability statistics were not applied, as the study design did not allow for this type of analysis. Patterns emerging from weekly POMS SF, adherence, satiety, and weight status were monitored and considered in the development of focus group schedule and classification. POMS data were presented as an average across participants from baseline to programme completion. Table 1 presents the schedule of questions generated for use in focus group discussions.
Table 1. Focus group schedule of questions
Focus groups were audiotaped and transcribed. Additional hand-written notes were taken by a research officer and used as a reference document to aid with focus group transcription. Data were analysed within QSR NVivo (version 10.1.0), allowing for classification and organisation of data. (24) The thematic analysis approach was used to analyse focus group data and examined themes emerging through participant responses. Focus group data were examined at the three categorised adherence levels: low adherence, medium adherence, and high adherence. Findings addressed participants’ perceptions of the concepts impacting their ability to adhere to the LCHF diet. This process involved the evaluation of textual data and identification and coding of identified and emerging themes.
Table 2. Participant age and body size characteristics at baseline
BMI: body mas index, expressed in kg/m2
In total, eighteen women expressed interest in participating in the study; all were issued with eligibility questionnaires, with 15 women considered eligible to participate in the study. Two respondents failed to meet the study eligibility criteria. One respondent withdrew from the study immediately post week one. Fifteen women completed the eight-week LCHF Women’s Health Research programme. Three focus groups were conducted involving all 15 participants.
Overall, mean percentage weight loss from baseline to study completion was 5.6% (range of 2.2kg – 8.6kg) (Figure 1). The high adherence group recorded the greatest weight loss, 7% (mean of 6.2 kg), concurrent with high self-report adherence (average adherence of 92.8%). The low and medium adherence groups (77.4% and 80.4%, adherence respectively) had a lower total weight loss (5.3% (mean 4.2kg) and 4.7% mean 3.8kg), respectively).
Focus group data
Four over-arching themes pertaining to adherence to the LCHF model emerged from the three focus groups while undertaking the LCHF diet: (i) Importance of support from family and peers, (ii) the need to be prepared, (iii) the feeling of fullness experienced, and (iv) the attitudes to acceptability of types of food recommended on the LCHF diet.
Table 3 outlines relevant key transcripts pertaining to the each of the themes identified. Note that focus group classification was based on participant adherence level on average over the eight-week study period. The levels comprised ‘Low Adherence’ (mean adherence 77.4%), Medium Adherence (mean adherence 80.4%) and High Adherence (mean adherence 92.7%).
Key findings from this research show that the LCHF dietary approach resulted in weight loss and improved mood states, with more weight loss noted for participants with greater adherence.
Four key themes emerged impacting adherence to these dietary modifications. Primarily, findings suggest self-reported adherence to this way of eating was achieved via a mechanism of improved satiety. In addition, both family support, and the acceptability of LCHF food options impacted participant’s ability to adhere to the LCHF dietary approach.
This research presents novel findings that both align with and add to the current body of literature around factors impacting adherence and acceptability of a carbohydrate-restricted dietary approach as a weight loss option for middle-aged women. This will be achieved by determining and addressing behavioural and environmental factors that impact dietary health behaviours in the population and relating them to the existing body of research.
Descriptive data collected throughout the study highlighted some expected and unexpected findings. Percentage weight loss was greatest in participants with the highest average adherence levels across the study period. While this reflects existing findings suggesting that adherence to weight-loss interventions impacts weight-loss outcomes, (17,25) as probability statistics were not applied to this data, the significance of these results remains uncertain. The overall average adherence level of 83.5%, while a self-report measure, was a positive outcome and reflected focus group results around factors that impacted adherence, such as feelings of fullness, and acceptability of LCHF food options, and family support.
An interesting result of descriptive statistics displayed in the POMS data was a clear indication of the decrease in both TMDS and TNMS in the initial two weeks of the study. This study was not designed to assess causative factors of the intervention on participant mood states. However, the obvious downward trend in TMDS and TNMS is an indication that the LCHF way of eating could positively impact mood states and this characteristic of the study warrants investigation in future studies.
All themes identified could be interpreted as both a barrier and motivator to adhering to dietary modifications.
While familial support is widely acknowledged as a contributing factor to adherence to a range of positive health behaviours, adherence to dietary modifications, in particular, is dependent on family support. (26-28) The current study findings on family support reflected those from earlier studies, whereby the support of family members emerged as a primary motivator to adhering to weight loss interventions. (29, 30) Dietary factors have been shown to impact immediate family members directly, therefore willingness by family, to adapt to and include the modified food choices in their own diet can enhance participant adherence. (28) Spousal involvement has been suggested as being of special importance in terms of providing emotional support for participants. (26,31) Indeed, results from the current study showed that participants experienced difficulties adhering when husbands were not supportive, however participants whose husbands provided support or partook in the LCHF way of eating reported feeling motivated to adhere to the LCHF dietary approach. These results align with those reported by Hammerstrom et al. (29) who found that husbands were both a major obstacle and a key motivator to adherence and behaviour change in women. In addition, when husbands refused to eat new food, requiring women to cook two meals, workload increased considerably, and created barriers to adherence to a diet. (29) Similar findings were reported by Gorin, et al. (28) who reported a recognition of the influence that environment holds over food choices, (28) and suggested that the home environment may be an important setting to target for intervention. Given that approximately 75% of daily calories are consumed within the home environment, (28) more research is warranted to determine how best to intervene and provide support in this setting. While environmental and behavioural changes that lead to weight loss and weight maintenance are required, future research should also investigate issues affecting food choices and preparation required when food is consumed outside of the home environment.
A subsequent theme, the importance of being prepared, was a theme that was also identified by Hammarström et al. (29) who reported improved adherence when participants were well prepared for a range of situations. Competing demands on participants in the current study and the requirement for time spent outside of the home environment created difficulties in managing mealtimes and snacks in the workplace and social and alternate environments. The associated study website provided information to guide participants on strategies to employ when eating outside of the home, including suggestions on how to adapt mainstream food options to be LCHF-appropriate. Limited choice of LCHF food options available in mainstream eateries such as cafes and bakeries, motivated some participants to create strategies to ensure LCHF food options were readily available. These actions are reflective of strategies outlined in the SDT, recognising that health behaviour is a function of characteristics of a person, their behaviour, and their environment. (32) Participants who became familiar with LCHF food options and established practices so that they were prepared for all circumstances displayed motivation to adhere. It is also probable that participants developed these strategies because of HBT applied to this study through tailored resources. The study resource was developed and implemented to support women through dietary behaviour change, providing a level and depth of information that promoted participant autonomy. Drawing from components of several health behaviour theories, combining TTM eliciting stages of change principles, SCT and SDT, resources were tailored to an individual’s current stage of change. (33) Participants were able to decide for themselves how much information they required and to what extent to access that information. Furthermore, it is apparent from these outcomes and those from previous studies that individuals with a lower self-efficacy for dietary change expect and therefore experience more barriers than motivators in daily life when intending to make a dietary change. (34) For example, participants who abstained from eating or were forced to manage with available options not appropriate on the LCHF diet, increased the likelihood of periods of non-adherence. This prerequisite for preparation created a barrier, with participants reporting that dietary modifications required additional effort in already busy lives. When LCHF practices became customary, time restraints became less burdensome, and food preparation routines were easier to adhere to. This finding is in keeping with TPB, whereby a person’s attitude toward a behaviour, and perceived behavioural control, combine to shape an individual's behavioural intentions and actions. (35) It must be considered that while many health behaviours require individuals to abstain permanently from a given behaviour (smoking cessation and drug abuse), food cannot be avoided completely. Therefore, dietary interventions need to be tailored to support participants to modify behaviour and sustain behaviour change in a food-dominated environment. Resources were developed in the context providing information that was easily accessible and support them to modify their behaviours in a range of situations. While individual engagement with specific resource components was not measured, participants commented that tri-weekly blog/posts added to a feeling of being supported and part of a wider group. This corresponds with research positing that participants benefit from the knowledge that they are part of a group, facing similar emotions and experiences. (36)
Satiety also emerged as a key theme contributing to participants’ ability to adhere to the LCHF way of eating in this research. Several participants reported a satiating effect of LCHF food options, reducing the amount and frequency of food required daily. This finding corresponds to results from several studies investigating macronutrient profile of diets and the subsequent impact on satiety levels. (29, 37, 38) The exact macronutrient most impacting satiety, however, remains uncertain. While some evidence suggests that the protein composition of a diet may increase satiety, (39) research by Volek et al. (38) suggest that both fat and protein are equally effective in improving satiety. These findings suggest that LCHF diets could be considered a preferred weight-loss strategy to their low-fat counterpart. This study, however, was not designed to assess how individual macronutrient composition of the diet impacted satiety, but rather the impact on satiety through the combination of food choices that were higher in natural fat than participants were previously consuming. Therefore, it was not possible to know for certain whether participants were adhering to recommended levels of protein and fat, or which nutrient most impacted their satiety. High and medium adherence groups reported that eating more fat was enjoyable and contributed to the feeling of fullness. In contrast, the low adherence group indicated a reluctance to take up high-fat food options. This is a probable result of existing public health messages advising against dietary fat intake. (21) It is also possible that participants in the low adherence group were often not satiated because of limited LCHF food options as a result of not being prepared for certain circumstances. It is well-recognised however, that hunger is not the sole motivator for eating, and alternative rationale exists explaining eating habits. Eating is influenced by emotional, social and environmental factors, and individuals frequently turn to food for comfort, stress relief, or as a reward.40 Furthermore food is seen as an important and enjoyable element of social and family gatherings making habitual eating habits harder to overcome. (40)
There are several limitations to this study, one being the use of self-reported measures. Participants received weekly questionnaire each Sunday afternoon through the eight-week study period. Self-reported adherence of participants to the LCHF way of eating may have been limited by issues of recall, comprehension, and social desirability bias. To mitigate this, food frequency questions were administered to prompt recall and provide consistency. However, the reliability of responses remains uncertain. While food frequency questionnaires (FFQs) are commonly administered in intervention studies to track changes in dietary choices, it is recognised that FFQs may not be sufficiently specific to detect change. Furthermore participants may report what they consider to be the desirable responses in context of the dietary approach, (41) limiting accuracy of these findings.
The introduction of food options, including those with a high-fat content previously avoided in substantial quantities, appeared to impact adherence positively. Participants’ enjoyment of specific foods including Greek yoghurt, almonds, and cheese was reported with participants commenting that these food options made the LCHF diet acceptable and agreeable. It is conceivable that the fat content of these foods also contributed to satiety and the possibility of increased adherence. Furthermore, when food options endorsed in the LCHF approach were acceptable to family members, adherence was enhanced. In contrast, however, barriers were created by family members not wanting to adhere to participants’ dietary modifications. Macchi et al. (42) recognised that modifying the types and amounts of foods prepared in the home may be perceived by family members as a challenge to existing family norms, posing further barriers for women in adhering to weight-loss interventions.
The current study suggests that satiety might have an important role to play in enabling adherence to an LCHF way of eating. The findings indicate that this dietary approach was both acceptable and feasible for study participants. Moreover, results showed that for this population group, the intervention design was appropriate and medium of delivery was effective. Further investigation is required, into adherence over a longer time-frame, and into acceptability and adherence issues with other population groups. The examination of weight loss approaches for middle-aged women specifically remains a relatively novel area of research. By changing their own health behaviours to a more positive model, women can influence the dietary behaviours of family members and those around them. They are therefore a key population group to consider when designing sustainable behavioural weight-loss interventions.
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