By Joseph E. Scherger, MD, MPH

Core Faculty, Eisenhower Health Family Medicine, Residency Program, Eisenhower Health Center, La Quinta, CA; Clinical Professor, Keck School of Medicine, University of Southern California, Los Angeles

SYNOPSIS: To lose body fat, a ketogenic weight loss diet must be combined with exercise.

SOURCE: Careau V, Halsey LG, Pontzer H, et al. Energy compensation and adiposity in humans. Curr Biol 2021;S0960-9822(21)01120-9. doi: 10.1016/j.cub.2021.08.016. [Online ahead of print].

Careau et al studied the data on adult total energy expenditure (TEE) and basal energy expenditure (BEE) in 1,754 people living normal lives. They found a typical person averages a 28% decrease in BEE with more exercise, negating much of the increased energy expenditure with exercise. Those with more adiposity recorded the greatest decline in BEE, making losing fat among the overweight and obese harder.


I tell patients that once it is there, the body wants to keep excess fat. This likely is an evolutionary survival adaptation that allowed our ancestors to keep hunting and survive famines. This biological adaption seems cruel to the overweight and obese population today. Energy expenditure alone (i.e., exercise) is not a successful weight loss approach.

The leading obesity researchers have shown that a low carbohydrate diet with intermittent fasting is required to achieve sustained weight loss, with or without exercise.1-3 Unfortunately, the food industry often resists this biological evidence, since most of the food profits come from processed carbohydrates. Sadly, many academic experts depend on food industry funding.


  1. Ludwig DS, Aronne LJ, Astrup A, et al.  The carbohydrate-insulin model: A physiological perspective on the obesity pandemic. Am J Clin Nutr 2021;nqab270. doi: 10.1093/ajcn/nqab270.
  2. Lustig RH. Metabolical: The Lure and the Lies of Processed Food, Nutrition, and Modern Medicine. 2021.
  3. Taubes G. The Case for Keto: Rethinking Weight Control and the Science and Practice of Low-Carb/High-Fat Eating. 2020.