Fast Weight Loss May Mean Muscle Loss

Fast Weight Loss May Mean Muscle Loss

THURSDAY, May 29, 2014 (HealthDay News) -- If you lose weight too fast, you lose more muscle than when you shed excess pounds more slowly, a small study says.

The researchers put 25 participants on a five-week very-low-calorie diet of just 500 calories per day. Another 22 volunteers went on a 12-week low-calorie diet of 1,250 calories per day.

The investigators found that right after the end of their diets, both groups had similar levels of weight loss. The average weight loss was a little over 19 pounds among those on the very-low-calorie diet and just under 19 pounds among those on the low-calorie diet.

The researchers then looked at the loss of fat-free mass, which includes all the tissue in the human body, except fat. The major tissues are blood, bones, organs and muscles. However, the mass of the organs, blood and bones does not change during dieting. Therefore, changes in fat-free mass during dieting are mainly due to changes in muscle mass.

Participants on the very-low-calorie diet had lost about 3.5 pounds of fat-free mass, compared with 1.3 pounds among those on the low-calorie diet. Fat-free mass accounted for 18 percent of weight loss in the very-low-calorie diet group and 7.7 percent of weight loss in the low-calorie diet group, the study found.

Four weeks after the end of their diets, reductions in fat-free mass averaged 1.8 pounds among those in the very-low-calorie diet group and 0.7 pounds among those in the low-calorie diet group. Fat-free mass accounted for 9.4 percent of weight loss in the very-low-calorie diet group and 2.9 percent of weight loss in the low-calorie diet group, according to the report.

The findings were presented Wednesday at the European Congress on Obesity in Bulgaria.

"Loss of fat-free mass was higher after rapid than slow diet-induced weight loss with similar total weight loss," said the study's authors, Roel Vink and Marleen van Baak, of the School for Nutrition, Toxicology and Metabolism at Maastricht University in the Netherlands, and colleagues.

However, the authors also pointed out in a meeting news release that muscle loss among people in the very-low-calorie diet was likely overestimated immediately after they completed the diet, compared with four weeks later.

This is likely because they had a larger loss of water and glycogen (a natural form of sugar in the body) when they had just completed the diet than four weeks later, the researchers explained.

Research presented at meetings should be viewed as preliminary until it is published in a peer-reviewed medical journal.

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases explains how to choose a safe and successful weight-loss program.

SOURCE: European Congress on Obesity, news release, May 28, 2014

 
Today's Interactive Tools

The third-party content provided in the Health Library of phoebeputney.com is for informational purposes only and is not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your physician. If you or your child has or suspect you may have a health problem, please consult your primary care physician. If you or your child may have a medical emergency, call your doctor or 911 or other emergency health care provider immediately in the United States or the appropriate health agency of your country. For more information regarding site usage, please visit: Privacy Information, Terms of Use or Disclaimer.