The lived experience of healthy adults following a ketogenic diet: A qualitative study

Abstract

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.