Why and how should adults lose weight?

Being overweight increases the risk of developing many common diseases including type-2 diabetes mellitus, hypertension, coronary heart disease, gallstones and various cancers of the gastrointestinal and urogenital tracts. It can also cause or exacerbate osteoarthritis, breathlessness, heartburn, sleep apnoea, venous thromboembolism and psychological distress, particularly anxiety and depression. It makes anaesthesia and surgery more hazardous, and in pregnancy increases the risks associated with childbirth. Being overweight can also complicate day-to-day social functioning such as negotiating seats on public transport or purchasing clothes. In this article, we review the evidence that weight loss is beneficial and how this might be achieved using lifestyle changes, drug therapy, or surgery.