Comparing 3 Popular Diets

Low-carb diet plate

Twenty nine year old Sam Feltham decided to do a study on himself to see what happened when he overfed himself by eating 5800 calories per day for 21 days.  He was comparing 3 popular diets and the result was unexpected :

1.    A low-carb / high fat diet

2.    A high carbohydrate / low fat diet

3.    A very low-fat vegan diet

For a 29 year old male, 5800 calories is equivalent to eating double your daily food intake.  He continued his 3 hours of cycling each week by cycling to work and had a 20 minute high intensity interval training workout 3 times per week.

He used the nutrition information on the food labels and from a supermarket website  www.asda.com to calculate his calories. He made sure that the calories were the same every day regardless of the diet. 

The result is fascinating.  The low fat diet increased weight and increased waist circumference the most compared with the others.  This study challenges any thought that a calorie is a calorie.

Diet	Calories / day	Carbs	Protein	Fat	Weight change Kg	Waist circumference change cm
Low-carb, higher fat	5794	5.9%	22.3%	71.8%	1.3	-3.0
Ultra low-fat vegan	5794	68.0%	16.5%	15.5%	4.7	7.8
High-carb, low-fat	5793	63.9%	13.5%	22.6%	7.1	9.3

On all diets he gained weight.  Not too surprising.  However, what is truly surprising is that the biggest weight gain came from the low-fat diet.

+7.1 Kilograms.

On both the low-fat diets his waist circumference increased with the greatest increase on the high carb / low-fat diet.  On the low-carb / high-fat diet (Keto like) his waist circumference actually decreased while he still added a little weight, +1.3 kgs.

Some of his comments (edited) are interesting:

“On the low-carb diet 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”.

“On the low-fat diet my asthma returned after 3 days, making it difficult to breathe during exercise. I began to snore, I felt lethargic and cognitively foggy.  I easily ate all the food by the end of the day”

“On the vegan diet, I was having to go to the toilet a lot. My asthma returned after 10 days, but I was not hungry. Similar to the low-carb diet, at certain points during the day I had to force feed myself to maintain calories.”

His results are fascinating. You can see why I don’t ever use calories as a measurement for food.

You can read all about the details of the 3 diets and his methods at:

https://journals.lww.com/co-endocrinology/fulltext/2021/10000/a_case_study_of_overfeeding_3_different_diets.5.aspx     Note: (If retyping this link, put underscore _ between words)

Seek medical advice before dietary changes, particularly if on medication.  George Elder, Certified Health Coach, Author, Diploma in Nutrition. 

The best thing you can do for your health is eat better