September 30, 2008

No Bone Loss in Dieters

Young adults on a diet low in calories but nutritionally sound for six months appear to lose weight and fat without a much bone loss, U.S. researchers say.

Leanne M. Redman and colleagues at Pennington Biomedical Research Center in Baton Rouge, La., studied 46 healthy, overweight men and women, who were randomly assigned to one of four groups for six months. Eleven formed the control group, who ate a healthy diet; 12 consumed 25 percent fewer calories than expended per day; 12 ate fewer calories and exercised five days per week; and 11 ate 890 calories per day until they achieved 15 percent weight loss, at which time they switched to a weight maintenance plan.

All diets included recommended levels of vitamins and minerals and contained 30 percent fat, 15 percent protein and 55 percent carbohydrates.

After six months, average body weight was reduced by 1 percent in the control group, 10.4 percent in the calorie restriction group, 10 percent in the calorie restriction-plus-exercise group and 13.9 percent in the low-calorie diet group.

The study, published in the Archives of Internal Medicine, found that compared with the control group, none of the groups showed any change in bone mineral density for total body or hip.