The World Health Organisation estimates that globally there are more than one billion overweight adults, of which at least 300 million are clinically obese. The prevalence of obesity across the seven major pharmaceutical markets is estimated at 114 million, and is predicted to increase to 138 million by 2013, with an additional 197 million classified as overweight.

The incidence of obesity has more than doubled in the US since 1980, and now approximately two thirds of US adults are overweight or obese. Obesity levels have tripled in many European countries since the 1980s, and the numbers of those affected are continuing to increase at a rapid rate.

Alarmingly, childhood obesity is rising, with 15% of US children and adolescents categorised as obese according to the American Obesity Association. Overweight and obese children are likely to become obese adults and suffer discrimination and economic disadvantages during their education and into adulthood in addition to the adverse health consequences.