Obesity paradox during aging.

Although obesity in young people is a risk factor for morbidity and mortality, the effect of obesity in the elderly is much more complex. For example, the body weight associated with maximal survival increases with increasing age. Even more striking is the 'obesity paradox' in the elderly, in which overweight is associated with increased risk for cardiovascular disease but decreased mortality from these diseases. Thus, although intentional weight loss by obese older people is probably safe, and likely to be beneficial if they have obesity-related morbidities, caution should be exercised in recommending weight loss to overweight older people on the basis of body weight alone. Methods of achieving weight loss in older adults are the same as in younger adults. Weight loss diets should be combined with an exercise program, if possible, to preserve muscle mass, as dieting results in loss of muscle as well as fat, and older people have reduced skeletal muscle mass compared to younger adults. Weight-loss drugs have not been extensively studied in older people and there is the potential for drug side effects and interactions. Weight loss surgery appears to be safe and effective, although it probably produces less weight loss than in younger adults. Little is yet known about the outcomes of such surgery in people over 65 years.