Crash dieting is giving you more belly fat and is even weakening your muscles. These are the findings of a new study by researchers at the Georgetown University in Washington, DC. Women are more likely than men to participate in crash diets in which body weight decreases rapidly and dramatically. Extreme dieting has short- and long-term risks with possible damage to the heart, kidneys and circulatory system.
Researchers examined female rats given a 60% calorie reduction in their diet, roughly comparable to reducing from a 2,000 calorie daily diet to an 800-calorie diet in humans. Within three days, the extremely reduced calories diet lowered body weight and caused cycling —similar to a menstrual cycle —to temporarily stop.
The diet also led to a decrease in a number of metabolic factors and functions, including body weight, blood volume, blood pressure, heart rate and kidney function. Returning to typical eating patterns quickly restored cycling, body weight, blood pressure and heart rate.
However, the animals had a higher accumulation of abdominal fat three months after the diet ended compared to animals that did not follow the diet. “Even more troubling was the finding that angiotensin II, a hormone in the body, was more potent at increasing blood pressure in the rats that were on the reduced-calorie diet,” said Aline de Souza, first author of the study.
Although the rats’ blood pressure levels in recovery remained normal, higher-than-normal blood pressure responses to angiotensin II may increase the risk of developing high blood pressure. Together with the increase in belly fat, these changes in body composition may cause long-term health risks for people who have previously crash dieted.
The findings were presented at a meeting of American Physiological Society (APS).