The national obesity epidemic is now so severe that fewer than two in five adults in England are a “normal weight”, according to new research.

One in ten children is obese by the time they start school, while there has been a sharp rise in the number of people admitted to hospital with obesity-related conditions.

About 24 per cent of men and 26 per cent of women were classified as obese in 2011, compared with 13 per cent and 16 per cent in 1993, when the data was first collected.

Counting obese and overweight people together, 65 per cent of men and 58 per cent of women are heavier than is healthy.

Graham Rowan, the chairman of the Obesity Management Association, warned that the epidemic was “spiralling out of control”.

Tim Straughan, the chief executive of the Health and Social Care Information Centre, which compiled the data, said soaring obesity rates coincided with a decline in healthy eating and a lack of exercise.

Household purchases of fresh and processed fruit and vegetables have fallen since 2008. Purchases of fruit were 4.1 per cent lower in 2011 than in 2008, while the volume of vegetables bought dropped by 2.4 per cent in the same period, including a 6.6 per cent drop in fresh green vegetables.