Analyzing the ketogenic diet's effects on body composition Original paper

The ketogenic diet has garnered much attention in the last decade, but findings on its effectiveness in improving body composition have been inconsistent. Studies have reported that the keto diet was more effective for reducing body fat than calorie-controlled diets, but some of these studies used a high protein/low carbohydrate approach instead of the 4:1 fat:nonfat ketogenic diet ratio.^[1][2] This study measured the effects of a high-fat ketogenic diet on various body composition measures.

This meta-analysis of 18 randomized controlled trials of 1,653 people investigated the effects of a ketogenic diet compared to a low-fat control diet. The researchers assessed the effects of the diets by monitoring body weight, BMI, waist circumference, fat mass, fat-free mass, lean body mass, visceral fat, and body fat percentage.

The ketogenic diet reduced body weight, BMI, fat mass, fat-free mass, waist circumference and visceral fat, lean body mass, and body fat percentage compared to a low-fat diet. Variability between studies was found for body weight, BMI (this measure was not reduced in studies that included only women), and fat mass.

Most of the trials in this meta-analysis were short (<6 months), so conclusions cannot be drawn about the long-term weight management benefits of the ketogenic diet. Also, it should be noted that severe carbohydrate restriction leads to immediate water weight loss due to the depletion of glycogen stores,^[3] which can create measurement errors in the tools commonly used to assess body composition.