Ghrelin stimulates growth hormone secretion, but it also has effects that are not attributable to increased growth hormone levels. A ghrelin mimetic transiently increases appetite, a novel effect that might counteract physiologic anorexia, a cause of weight loss in elderly persons (26–27). Unlike growth hormone, which is lipolytic, ghrelin increases fat stores. We found that body weight increased more in MK-677 recipients than in placebo recipients. Although total fat mass increased in both groups, limb fat and limb lean mass increased more in participants receiving MK-677 than in those receiving placebo. Surprisingly, thigh muscle cross-sectional area did not increase, although our study was not powered to detect small but potentially important differences because the single-slice computed tomography method that we used was insufficiently precise. Growth hormone reduces abdominal visceral fat in growth hormonedeficient adults (28) and abdominally obese, postmenopausal women (29) but not in normal elderly participants (30). Although MK-677 increased growth hormone levels, it did not affect abdominal visceral fat, possibly because its combined orexigenic and adipogenic effects counteracted the lipolytic effects of enhanced growth hormone. Finally, although MK-677 did not reduce abdominal visceral fat, it did reduce low-density lipoprotein cholesterol levels at 12 months, an effect not seen with growth hormone in normal elderly participants (8).