Body mass trajectory, energy balance, and weight loss as determinants of health and mortality in older adults.

The relationship between body mass (usually measured as BMI in kg/m(2)) and healthy longevity is a major focus of study in the nutrition and aging field. Over-nutrition now rivals frailty as the major nutritional concern; the number of older adults who are obese has increased dramatically in the past 3 decades. While obesity exacerbates a host of life-threatening, age-related chronic diseases, a somewhat paradoxical finding is that being somewhat overweight in old age appears to be a benefit with regard to longevity. In our recently completed systematic review of randomized controlled weight reduction trials, we found that weight loss interventions in overweight/obese older subjects led to significant benefits for those with osteoarthritis, coronary heart disease, and type 2 diabetes mellitus, while having slightly negative effects on bone mineral density and lean body mass. In contrast to this finding, the preponderance of epidemiological evidence indicates that higher BMIs are associated with increased survival after age 65 years. Because of this contradictory state of the science, there is a critical need for further study of the relationship of weight and weight loss/gain to health in the later years of life. Copyright 2009 S. Karger AG, Basel.