A case study of overfeeding 3 different diets - 2021

Purpose of review - Quality or quantity of food has been at the heart of the diet debate for decades and will seemingly continue for many to come unless tightly controlled studies are conducted. To our knowledge, there has never been an overfeeding study comparing the effects of multiple diets.

Recent findings - This study reports a case study of an individual who ate 5800 Calories per day of 3 different diets for 21 days at a time. The 3 different diets were low-carb, low-fat, and very-low-fat vegan. The weight gain over 21 days was 1.3 kg for low-carb, 7.1 kg for low-fat, and 4.7 kg for very-low-fat vegan.

Summary - In this n-of-1 study, consuming 5800 Calories/day of 3 different diets for 21 days did not lead to the same amount of weight gain. Further research should be conducted on how the human body gains weight with an emphasis on how different foods affect physiology. If these findings are replicated, there would be many ramifications for obesity treatment and healthcare guidelines.

Full Text: https://doi.org/10.1097/MED.0000000000000668

Ben Bikman brought up this study, and made a nice summary slide for it

3 comments

For decades, experts have taught that obesity is caused by excessive caloric intake relative to expenditure and that the macronutrient composition of the calories was of lesser importance, or of no importance at all. Obesity is the ‘result of disequilibrium between energy intake and expenditure [1].’ The problem with focusing on calorie/energy balance as the explanation for obesity is that it does not ask why there is an imbalance, and whether different macronutrients may have different hormonal effects [2].
This really demonstrates that insulin (hormones) are far more impactful on body composition then CICO.
If the macronutrient composition of the diet is irrelevant, then caloric restriction to the same level would have absolutely the same effect. However, several observations suggest otherwise. Recent randomized, controlled trials comparing low-carb to low-fat diets show different effects in terms of weight loss, and changes in cardiometabolic risk factors [3]. More carefully controlled studies of metabolic rates can detect differences in changes for different diets of the same caloric level, but different macronutrient composition
Yeah, exactly this. Metabolism is controlled by hormones. Hormones CAN be forced by carbohydrates.
5800 calories per day three diets (keto, low fat, low fat vegan) for 3 weeks
3 month washout period between diets.
Low Carb 3 week results:
My experience during this diet was mainly a happy one. I had lots of energy, could exercise normally and I was never hungry. In fact at certain points during the low-carb diet I had to force feed myself when I was full. Especially in the evening when I had to eat 967 k/cals of almonds after 771 k/cals of steak and green beans.
Low fat 3 week results:
My experience during this diet was not a happy one. Within 3 days my asthma had returned, which made it difficult to breathe during exercise and whilst I was sleeping. This in turn disrupted my sleep and I began to snore. In general, I felt lethargic and cognitively foggy. Converse to the low-carb diet, on the low-fat diet I easily ate all the food by the end of the day and probably could have managed more
Very-low-fat vegan diet:
My experience during this diet was not a happy one. My fiber intake was 178 g per day, and so the main side effect was that I was having to go to the toilet a lot, which was unsettling. Cognitively I was also foggy and after about 10 days my asthma had returned, which made it difficult to breathe during exercise and whilst I was sleeping. The difference with the low-fat diet was that I was not hungry. Similar to the low-carb diet, at certain points during the day I had to force feed myself.
It is possible that the biochemistry involved in processing different foods reason leads to such differing outcomes between the diets. One possible explanation may be the differences in the glycemic index/insulin response of foods: the low-carb diet was made up of low insulin response foods, the low-fat diet was made up of high insulin response foods and the very-low-fat vegan diet was made up of medium/high insulin response foods
I think this must be the case. It fits well with the other literature
This is a very well thought out n=1 case study, I recommend reading it. Especially if your position is that obesity is just a failure of CICO.
- It is remarkable that such physiological changes occur even after a comparatively short period of only twenty-one days. Having tried all three also, my experience has been consistent with this in general; however I do not have asthma, and I was noticeably much more irritable on low-fat and very-low-fat vegan.
  I'm curious as to how he "reset" his body state to keep the starting point consistent for the study. It would've also been interesting if he'd also adopted a high-fat animal-sources-only diet as part of this trial.
  The limitations of this study include just one subject was studied, and he was generally in good health and exercised regularly, so these findings may not apply to a individuals with medical problems. Additionally, these results may not extrapolate to ALL types of low-carb or low-fat diets, as there is a wide range of food choices within each of these general diet descriptions.
  I also appreciate that the limitations are clearly stated. Interesting study!
  
  Yeah! I would have liked to see more biomarkers too. But I think the point of this project was to illustrate how limited the current literature is.
  The 3 month reset could have been better defined, to be sure. The fun thing is anyone can repeat this data finding experiment and collect better metrics.
  This is exactly what I mean when I say the carnivore community, as a whole, is very scientifically minded. I.e. can they repeat the results