Studies have identified major risk factors for cardiovascular disease (CVD). Some are non-modifiable but many reflect lifestyle habits, such as a deleterious diet and lack of physical activity/exercise, which lead to overweight and obesity.1 2 Obesity has reached epidemic proportions in the United States as well as much of the industrialised world, and is increasing in the developing world.3^–6 In the most widely used classification of body mass, body weight is expressed as a body mass index (BMI).3 In adults, obesity is defined as a BMI ⩾30 kg/m² which is further subdivided into grades (box 1). Obesity has also been defined in children.4

The most rapidly growing segment of the obese adult population is that comprising people who are severely obese. Between 1986 and 2000, people with a BMI >30, 40 and 50 kg/m², are reported to have doubled, quadrupled and quintupled, respectively, in the United States.7 Data indicate that the prevalence of extreme obesity in children is increasing.4 It has been suggested that the life-shortening effect of obesity could increase as the obese who are now at younger ages carry their increased risk of death into middle and older ages.8 The estimated years of life lost due to obesity differ among races and gender and it was estimated that the optimal BMI for adults aged 18–85 years is 23–25 kg/m² for white subjects and 23–30 kg/m² for black subjects.9 However, obesity is a remarkably heterogeneous condition.10 11 Obesity as defined by the BMI is undoubtedly associated with an increased rate of comorbidities and cardiovascular mortality10 12 and obese people considered “at risk” are mostly characterised by features associated with metabolic disturbances.12 13 The epidemic of obesity is occurring on …