One in five Britons has a dangerously expanding waistline

The United States has the largest share of obese people in the western world, but Britain is not far behind with one in five adults classed as dangerously overweight.

The United States has the largest share of obese people in the western world, but Britain is not far behind with one in five adults classed as dangerously overweight.

Waistlines are expanding at a worrying rate because of inactive lifestyles, widespread over-eating, and diets which are packed with high-fat and energy-dense foods, rather than carbohydrates. This is made worse by the popularity of takeaway food, eating out, and the extensive marketing of processed foods, which contributes to over-consumption.

Greater car ownership, the a decline of walking, and a greater use of lifts and escalators have taken their toll. Compared with today, it is estimated that the extra physical exercise involved in daily living 50 years ago equated to running a marathon each week.

Just one-third of secondary pupils now spend two hours or more playing sport at school. At the same time, television viewing has increased from an average of 13 hours a week in the 1960s, to more than 26 hours a week in the 1990s.

The result is a tripling of obesity since 1980, when just 7 per cent of adults were affected. Now the problem accounts for 30,000 premature deaths a year and costs the NHS up to £2bn in treatment, according to the National Audit Office.

Unless more is done, one in four adults will be classed as obese by the end of the decade, which would match the prevalence of the problem in the US.

Apart from the psychological side effects, obesity increases the risk of heart disease, strokes, diabetes, cancer and other conditions such as osteoarthritis.

Nearly all obese people will develop some associated medical condition by the time they are 40, and most will need medical care before they are 60. Among adults, weight problems can cause low self-esteem, reduced sex drive, and serious depression. Children who are overweight suffer bullying and discrimination. They are also much more likely to be obese in adulthood than children who are a healthy weight.