The obese are subject to health problems directly relating to the carriage of excess adipose tissue. These problems range from arthritis, aches and pains, sleep disturbance, dyspnea on mild exertion, and excessive sweating to social stigmatization and discrimination, all of which may contribute to low quality of life and depression (Table 1). The most serious medical consequences of obesity are a result of endocrine and metabolic changes, most notably type 2 diabetes mellitus, cardiovascular disease, and increased risk of cancer. Not all obesity comorbidities are fully reversed by weight loss. The degree and duration of weight loss required may not be achievable by an individual patient. Furthermore, "weight cycling" may be more detrimental to both physical and mental health than failure to achieve weight loss targets with medical and lifestyle advice.