Type 2 Diabetes Mellitus (T2DM) is a disease of over nutrition; the onset and progression of which, is associated with excess fat accumulation in the abdomen, muscles and liver. In this review, we focus on management of obesity as the primary strategy for management of disorders of glucose metabolism. Modest weight loss (∼7%) achieved by diet and exercise can prevent, or delay, the onset of T2DM. In those with established T2DM, weight loss reduces fasting and post-prandial plasma glucose levels, HbA1c, and the need for pharmacotherapy. The beneficial effects on glucose metabolism of caloric restriction, and aerobic and resistance exercise, may occur independently of weight loss. When substantial weight loss is required, meal replacements allow a large reduction in energy consumption whilst maintaining micronutrient intake. Pharmacotherapy for obesity, as part of an integrated management plan, is useful for maintaining weight loss and optimising glycaemic control. The most effective long-term therapy for obesity remains bariatric surgery, which is associated with resolution of T2DM in over 80% of patients. The currently available pharmacotherapies for T2DM mostly result in weight gain. Pramlintide and exenatide are new therapies which hold promise, because in addition to improved glycaemic control, they also result in weight loss.