A higher-protein diet that emphasizes lean meats and low-fat dairy foods as sources of protein and calcium can mean weight loss without bone loss. The evidence is in bone scans taken throughout a new University of Illinois study, funded by the Illinois Council on Food and Agricultural Research, the National Cattlemen's Beef Assn., The Beef Board, Kraft Foods and the USDA, and published in the Journal of Nutrition.
The study followed 130 middle-aged, overweight persons at two sites — the U of I and Pennsylvania State University — for a year. Comparing the results of a high-protein, dairy-intensive diet (representing 30 percent of all calories) with a conventional weight-loss diet based on the Food Guide Pyramid, the study found that protein-rich weight-loss diets preserve muscle mass, help lower blood sugar and lipids and improve body composition by targeting weight carried in the abdomen.
Participants also ate five servings of vegetables and two to three servings of fruit each day. Bone mineral content and density were measured with DXA scans of the whole body, the lumbar spine and the hip at the beginning of the study, at four months, at eight months and at the end of the 12-month period.
"This is an important finding because many people, especially women in mid-life, are concerned with both obesity and osteoporosis," said Ellen Evans, a U of I associate professor of kinesiology and community health and member of the university’s Division of Nutritional Sciences. "Furthermore, treating obesity often increases risk for osteoporosis. Many people lose bone mass when they lose weight," she said.
For more information, visit www.jn.nutrition.org/cgi/content/short/134/3/586.