Obesity increases the risk of developing type II diabetes. However, the link between the two remains unclear, although insulin resistance and visceral adiposity are dominant risk factors. A study with CT scanning confirmed that the degree of visceral adiposity had a significant positive correlation with insulinaemia, and was negatively associated with insulin sensitivity. A 48 month retrospective study in patients with type II diabetes, who had received dietary therapy, identified a 'responder' group in whom metabolic improvements accompanied weight loss. Preferential loss of visceral fat may be an important factor in these 'responders'. Patients losing > 6.9 kg (or at least 10% mean baseline body weight) have demonstrated significant improvements in their glucose, HbA1 and lipid profiles. Modest weight loss by patients with type II diabetes therefore improves glycaemic control, insulin sensitivity and cardiovascular risk factors; and the risk of developing long-term diabetes-related complications may also be reduced by such metabolic improvements.