Obesity is now the most common nutritional disorder in western industrialised countries. Defined as a body mass index of greater than 30, it arises from the accumulation of excess fat in the body from over consumption of fatty foods. Prevalence of obesity in the US and Europe has reached epidemic levels.

Data from the World Health Organisation’s MONICA project show that in some parts of Europe over 70% of men aged 55-64 years are clinically obese or overweight (BMI >25) and almost 70% of women in this age group. One in five of all Americans is obese and one in three overweight. Furthermore, increasing rates of childhood obesity are likely to exacerbate the trend towards increasing obesity in adulthood.

There is a strong association between obesity and increased risk of cardiovascular disease and diabetes and possibly certain cancers, such as breast and colorectal cancer.

The dramatic rise in the incidence of type 2 diabetes is due largely to the increased prevalence of obesity. Increases in body weight lead to changes in blood lipid and cholesterol levels, predisposing to increased risk of atherosclerosis.