Sleep deprivation appears independently associated with weight gain, particularly in younger age groups. According to researcher Nan Hee Kim, MD, PhD, of Korea University College of Medicine in Ansan, Korea, regardless of lifestyle, people who stayed up late faced a higher risk of developing health problems compared with those who were early risers. Late-to bed individuals are more likely to develop diabetes, metabolic syndrome, and sarcopenia (loss of skeletal muscle mass and strength as a result of aging) than early risers, even when they get the same amount of sleep. Male night owls were more likely have diabetes or sarcopenia than early risers. Female night owls tended to have more belly fat and an increased risk of metabolic syndrome, which raises the risk of heart disease, stroke, and diabetes.