Study: Dairy Foods and Protein Help Preserve Muscle While Losing Fat

Researchers sought to determine how daily exercise and a reduced-calorie diet varying in total protein and dairy foods affected the composition (i.e., muscle and fat) of weight lost.

Aug 31 2011 --- New research indicates that diet- and exercise-induced weight loss with higher protein and increased dairy product intakes improves weight loss quality by promoting more favorable body composition changes in overweight and obese women. The study, co-funded by the Dairy Research Institute, Dairy Farmers of Canada and the Canadian Institutes of Health Research, was conducted by McMaster University, Ontario, Canada, and is now available online on the Journal of Nutrition website.

Researchers sought to determine how daily exercise and a reduced-calorie diet varying in total protein and dairy foods affected the composition (i.e., muscle and fat) of weight lost.

Ninety otherwise healthy, premenopausal, overweight and obese women who were habitually low dairy consumers were randomized into one of three groups: high protein/high dairy, adequate protein/adequate dairy and adequate protein/low dairy. The dairy foods consumed included low-fat milk and yogurt and full-fat cheese. All participants achieved a net reduction of 750 calories per day through a combination of reducing food intake and increasing exercise.

All groups lost similar amounts of body weight and total body fat over the 16-week study. However, the high protein/high dairy group, which obtained half their protein intake through dairy foods, lost more abdominal fat compared with the adequate protein/low dairy group. This is important to note as there is a strong association between abdominal or centrally located body fat and the risk for cardiovascular disease. The high protein/high dairy group also experienced an increase in lean body mass, while the adequate protein/low dairy group experienced a decrease in lean body mass.

While calorie reduction alone can lead to weight loss, the weight lost often includes not only fat, but also lean muscle. This research supports previous studies showing that higher protein diets during weight loss may help preserve muscle while losing fat. Additionally, this study demonstrates that this higher protein diet can be achieved through an increase in dairy foods.

“We know that regular exercise and calorie restriction is important for any weight-loss plan, but this study confirms that higher intakes of protein and dairy foods can improve the quality of that weight loss,” said Gregory Miller, Ph.D., president of the Dairy Research Institute.

The Dairy Research Institute is an organization that, along with other sponsors, is funded by the dairy checkoff and established by dairy farmers with a commitment to product, nutrition and sustainability research. Better understanding the value of dairy protein on weight control and improved health is a key priority area for the Dairy Research Institute.

“Our research shows that higher protein intakes, and dairy in particular, could offer important benefits to those on a weight-loss plan involving diet and exercise” said Stuart M. Phillips, Ph.D., department of kinesiology, McMaster University. “The high protein/high dairy group ultimately exhibited greater total and abdominal fat loss and lean muscle gain.”

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