A new study shows that reducing your daily caloric intake by 300 calories can have a beneficial impact on health. We’ve long known that most laboratory animals kept on calorie-restricted diets live longer and enjoy better health. The new study suggests that the same strategy also appears to work for humans. It found that cutting about 300 calories a day for two years improved cholesterol levels, blood pressure, and blood sugar and reduced inflammation among the 143 healthy men and women who participated. All were under the age of 51, and most were not overweight, although some carried a few extra pounds. No such health improvements occurred in a control group of 75 healthy people who didn’t cut calories.
The study took place at Duke University and was designed to help the participants pare 25 percent of their total calories. Most weren’t able to keep their calorie count that low on average they were able to reduce it by about 12 percent. Over the two years, they dropped an average of about 10 percent of their weight.
During the study the participants could eat whatever they wanted as long as they cut back on the total amount of food consumed. For the first month they ate three meals a day designed to reduce their caloric intake by 25 percent in preparation for the diet. They also had individual and group counseling sessions for the first six months and after that met with researchers periodically.
Some of the benefits seen among those who cut calories stemmed from weight loss, an average of about 16 pounds over the two years. But study leader William E. Kraus, M.D., a cardiologist and distinguished professor of medicine at Duke, said the overall health improvements seen were greater than would be expected from weight loss alone. “We weren’t surprised that there were changes,” he added, “but the magnitude was rather astounding. In a disease population, there aren’t five drugs in combination that would cause this aggregate of an improvement.” He added, “There’s something about caloric restriction, some mechanism we don’t yet understand” that results in better health.
We also don’t know whether cutting calories by 12 or even 25 percent can extend human life in the same way low-calorie diets can in animals. But if you have high blood pressure or high cholesterol or any of the other health problems that improved in this study, cutting 300 calories a day just might help you overcome them.
Andrew Weil, M.D.
William Kraus et al, “2 years of calorie restriction and cardiometabolic risk (CALERIE): exploratory outcomes of a multicenter, phase 2 randomized controlled trial,” The Lancet: Diabetes & Endocrinology, July 11, 2019, DOI: https://doi.org/10.1016/S2213-9597(19) 2015-2