The Summary
This clinical trial sub-analysis evaluated how different weight-loss diets affect resting energy expenditure (REE) in 102 adults with obesity. Over three months, participants followed one of five calorie-restricted plans (each with a 600 kcal/day deficit): a standard Mediterranean diet, a ketogenic diet, early or late time-restricted eating, or alternate-day fasting. Researchers measured REE using indirect calorimetry. The study revealed no significant differences in metabolic rate trajectories among the diets. Instead, individual REE changes were driven almost entirely by biological sex and changes in total body weight, regardless of the dietary strategy used.
Why this is interesting
Many believe that keto or intermittent fasting offers a "metabolic advantage" that prevents the metabolic slowdown typically caused by dieting. This study challenges that notion, showing that your resting metabolism doesn't care whether you limit carbs, skip breakfast, or fast every other day. When calories are restricted equally, the impact on your metabolic rate is virtually identical across all these approaches. Ultimately, your sex and body weight dictate your metabolic rate, meaning the best diet is simply the one you can stick to long-term.