The size of the waistline is the key to selecting patients to investigate. People who are genetically predisposed and who take in an excessive amount of calories are most likely to develop this condition. The lean man with a pot belly, a shape seen commonly in general practice, could be considered the most toxic shape of all. Objective assessment of known risk factors (cholesterol, fasting lipids, blood glucose level, blood pressure, smoking, obesity and sedentariness) is also necessary. Risk factors for metabolic syndrome often cluster together and have a multiplicative rather than an additive effect. In women, it is the level of fasting triglycerides, rather than cholesterol, that predicts subsequent cardiovascular disease and death. Waist target parameters have tightened over time and vary according to genetic polymorphism (see table below). If BMI is >30kg/m2, central obesity can be assumed and waist circumference does not need to be measured. Abnormal blood glucose should be in...