Recently, a group of Spanish researchers analyzed the long-term effects of low-calorie ketogenic diets on obese patients who wanted to lose weight.
Ketogenic diets are diets that are high in fat and protein and very low in carbohydrates. This diet is meant to predominantly burn fats as an energy source. Research has proven that when the human body is experiencing energy restriction—a common occurrence with diets—human bodies tend to lower the amount of energy being used up by decreasing the resting metabolic rate (RMR).
Scientists use the term metabolic adaptation to describe this RMR decrease and a related decrease in energy being used. Resting metabolic rate is essentially the amount of energy needed for the human body to perform basic activities while it is resting, such as breathing and brain functions.
Some ground-breaking research on ketogenic diets showed that extremely low-calorie ketogenic diets were capable of causing weight loss and assisting people in maintaining that weight loss for a period of up to two years. Some Spanish researchers conducted this study because they wanted to test the hypothesis that very low-calorie ketogenic diets trigger a neutral reaction in terms of resting metabolic rate. They theorized that this would diminish the likelihood of body weight regain. Their intriguing results were recently published in the Nutrition & Metabolism journal.
Ketogenic Diets Led to Sustained Weight Loss
The low-calorie ketogenic diets the researchers had the obese patients follow did result in maintained weight loss, however, the diet did not lead to the expected RMR decrease. They suspect this neutral RMR reaction might have occurred because lean muscle mass is often preserved when following this diet.
These authors assert that this study is the first, to their knowledge, that directly investigates the effects of low-calorie ketogenic diets on the resting metabolic rate of a sample of obese patients. The findings presented by these researchers demonstrated that a low-calorie diet was effective in maintaining normal resting metabolic levels, preserving lean muscle mass, and ultimately preventing metabolic adaptation—and perhaps weight regain for obese patients.
Written by Melissa Booker
Reference: Canton, A., Ordoñez-Mayan, L., … Casanueva, F. F. (2018). Resting metabolic rate of obese patients under very low calorie ketogenic diet. Nutrition & Metabolism, 15(1), 18. https://doi.org/10.1186/s12986-018-0249-z