BONE LOSS ACCOMPANYING DIET-INDUCED OR EXERCISE-INDUCED WEIGHT-LOSS -A RANDOMIZED CONTROLLED-STUDY

OBJECTIVE: To compare the effects of two weight loss interventions, di et or exercise, on changes in bone, fat and lean tissue. DESIGN: Prosp ective, long term, worksite, randomised and controlled weight-loss stu dy using a low fat diet ad libitum or moderate aerobic exercise. SUBJE CTS: 66 overweight men (mean age 43.4 +/- 5.7 y, BMI 29.0 +/- 2.6 kg/m (2)). MEASUREMENTS: Body weight, lean mass, fat mass, bone mass (BMC). bone mineral density (BMD) by dual-energy X-ray absorptiometry. RESUL TS: Dieters lost 1.4% BMC (1.5% BMD) with 6.4 kg weight loss; there wa s no significant change in BMC (or in BMD) in exercisers (2.6 kg weigh t loss) or in control subjects (no weight change). Changes in BMC were correlated with fat loss with both interventions: 11.7 g BMC/kg fat l oss in dieters, 11.4 g BMC change/kg fat loss in exercisers. CONCLUSIO N: BMC loss with diet-induced weight loss reflects loss of weight and especially loss of body fat. Further study to determine whether simila r BMC loss will accompany equivalent weight loss induced by exercise i s needed.