Plant-Based Beats Keto Diet for Fat Loss

Recent findings published in the top-tier journal Nature Medicine come from the very first trial to directly pit a plant-based diet against an animal-based ketogenic (“keto”) diet to shed light on how these approaches affect food intake and body composition. The results were clear: subjects who ate a carbohydrate-rich plant-based diet ate more food but lost body fat and retained their muscle, while the same people ate less food but retained body fat and lost muscle when they ate a keto diet.

Twenty adults in their late 20s and early 30s checked into the National Institutes of Health Clinical Center on two separate occasions to trial each diet, with researchers carefully monitoring how their bodies responded. They found that only when the subjects ate plant-based did their body fat drop. The researchers attributed this in part to the high fiber content of plants.

While many people think they need to eat tasteless foods and deal with chronic hunger to lower their body fat, this study proved otherwise, since participants reported no significant changes in hunger, fullness, familiarity, satisfaction, or pleasantness of meals. In other words, the plant-based diet, but not the keto diet, also had clear benefits for appetite control — without producing feelings of deprivation — despite producing considerable fat loss.

Fat-free mass, like muscle, also responded better to plant-based eating, compared to the keto diet. People usually lose some muscle along with body fat when they’re cutting, but when they ate plant-based, their muscle stores were left largely intact. However, when they ate a keto diet, their body stores of protein, like muscle, actually decreased — despite consuming a lot of protein. These findings align with the study that James Wilks discussed in The Game Changers when he said that “an eight-week weight-training trial also found that those consuming a normal amount of carbs gained 2.9 pounds of muscle mass, while those in the low-carb group actually lost muscle.”

As the studies roll in, it’s becoming increasingly clear that, for better body composition (and health in general), plant-based eating is our best bet.

References

Hall KD, Guo J, Courville AB, et al. Effect of a plant-based, low-fat diet versus an animal-based, ketogenic diet on ad libitum energy intake. Nat Med. 2021;27(2):344-353. doi:10.1038/s41591-020-01209-1

Vargas S, Romance R, Petro JL, et al. Efficacy of ketogenic diet on body composition during resistance training in trained men: a randomized controlled trial. J Int Soc Sports Nutr. 2018;15(1):31. Published 2018 Jul 9. doi:10.1186/s12970-018-0236-9