Dieting without exercise causes bone loss
If your patients are trying to lose weight, recommend both diet and exercise, not just diet, say researchers.
In a study by a team of nutritionists, physicians, and others at the University of Washington School of Medicine in Seattle, 30 postmenopausal women and 18 men, all overweight and 50-60 years of age, were randomized to one of three groups for a year: calorie restriction to decrease energy intake by 20%, an exercise program to increase energy expenditure by 20%, or no change. The participants kept diet and exercise diaries and visited a university clinic periodically so investigators could monitor compliance.
At the conclusion of the yearlong study, both the diet and exercise groups had lost a similar amount of weight—about 10%. But while the exercise group didn’t lose any bone mass, the diet group lost significant mass in the hip and spine, two common sites of fracture. There were no changes in the control group.
“Exercise has the important advantage over calorie restriction of protecting against bone loss,” the investigators say. “However, because the amount of exercise required to achieve meaningful weight loss is large, a more practical approach for weight reduction is a combination of calorie restriction and exercise” (Arch Intern Med. 2006;166:2502-2510).