Is your diet making you lose more than weight?

Bethesda, MD -- At least 50% of American women consume weight-reduction diets at some time in their lives -- and most women participate in some type of physical activity to lose weight. Although a healthy diet and exercise are key elements to living a healthy lifestyle, new research shows that women who want to lose a few pounds need to plan their weight loss programs carefully to avoid long-term problems like osteoporosis.

A recent study in the American Journal of Clinical Nutrition found that a lifestyle intervention program utilizing a low-fat diet combined with moderate exercise resulted not only in the desired weight loss but also in loss of critical bone mineral density at the hips and lumbar spine. Women who participated in the weight-reduction program lost an average of 7 pounds during the 18-month study period; however, these women also lost two times more bone mineral density than women who did not modify their diets or exercise patterns.

According to lead author of the study Loran M. Salamone, PhD, of the University of Pittsburgh Graduate School of Public Health, "Women need to evaluate the risks and benefits of their weight-reduction program. Dieting without adequate amounts of exercise can have potentially detrimental effects on bone mineral density and can increase the risk of developing osteoporosis. The ideal program is one that achieves weight loss while maintaining skeletal integrity."

In this study, women in the intervention group maintained calcium intake at or above the recommended dietary allowance by consuming low-fat milk, cheese, or yogurt, or by taking calcium supplements. However, there are many other factors involved in the formation and degeneration of bone mineral density. The women who increased their physical activity to a "high" level (defined as more than 4180 kJ/wk) had significantly less bone loss than women who had "low" levels of physical activity. This study provides strong evidence that modest weight reduction without adequate amounts of exercise can result in greater rates of bone loss over the short term. The long-term effects of weight reduction on bone loss are currently under investigation.

This media release is provided by The American Society for Nutritional Sciences and The American Society for Clinical Nutrition Joint Public Information Committee to provide current information on nutrition-related research.