The number of people worldwide with diabetes mellitus is likely to double in the next 10 years (estimated to be 221 million people). The explosion of type II diabetes relates to three linked factors--increasing prevalence of obesity, declining physical activity, and a genetic predisposition. Inheriting a metabolic profile that enhances survival through the reproductive years may be detrimental to well-being in times of plentiful food and sedentary existence. The obesity prevalence figures for England and Wales cause further alarm, with the prevalence in adult men (defined as a BMI,> 30 kg/m 2) rising to 14% and in adult women to 17%. In North America, the American Heart Association has upgraded obesity from a contributing to a major risk factor for coronary heart disease in recognition of the associated high rates of morbidity and mortality.

The modified diagnostic criteria for diabetes, which have been adopted by the American Diabetes Association and are proposed by the WHO, continue to cause contention. In particular, lowering the fasting plasma from 7.8 mmol/L to 7 mmol/L and the place of the oral glucose tolerance test remain controversial. The proposed criteria appear logical and practical for screening at-risk subjects, but correlate poorly with the previous adopted criteria for diabetes. Moreover, they may significantly alter both the incidence and overall prevalence of the disease.