Obesity

What is obesity

A minority medical condition 50 years ago, the prevalence of obesity is now such that it is regarded as a major public health issue and listed as a priority by senior government ministers.

A person is considered obese when their body weight reaches an excessive level. In the UK, clinicians generally use the Body Mass Index (BMI) to measure obesity. BMI is obtained by dividing a person's weight in kilograms by their height in metres squared. A BMI between 18.5 and 25 is considered "normal". A BMI over 25 is classed as "overweight" and a person is obese once their BMI reaches 30.

Obesity as a public health issue does not seek to make aesthetic judgements about people carrying extra body fat. Obesity is linked to a number of illnesses and reduced lifespan and the government is keen to reduce the prevalence of obesity among the population.

Background

Obesity is a relatively modern phenomenon; whereas past governments were concerned with inadequate nutrition and underweight children, politicians now launch initiatives against childhood obesity and encourage voters to slim down.

Now nearly a quarter of adults in England are obese, with obesity having tripled since the 1980s. By 2050 it is estimated that 60 per cent of men and 50 per cent of women will be severely overweight. Obesity among children has also increased to unprecedented levels.

Being overweight used to be seen as a personal medical complaint, largely blamed on genetics or constitution. The rising prevalence of obesity has forced health professionals and politicians to consider the lifestyle factors contributing to expanding waistlines.

It is now generally accepted that an imbalance between energy consumed in the form of calories and energy used causes weight gain or loss. This means sedentary lifestyles combined with the easy availability of calorie rich foods presuppose a population towards obesity.

Just a third of men and a quarter of women claim to achieve the recommended 30 minutes of exercise five times a week. Half of those not taking part claim their health is not good enough to exercise and nearly one in five say they do not have time. Working patterns have seen Britons shift to office-based jobs and longer working hours at the same time as rising obesity levels.

The prevalence of fast food chains and cheap, nutritionally poor food has led many to blame diet for rising obesity and many health campaigns focus on the importance of low-fat or low-calorie food choices. Although this is a common sense approach it should be noted that total energy intake fell by 20 per cent between 1974 and 2004, precisely those years when obesity soared.

Politicians are concerned by obesity because of the effect it appears to have on a person's general health – and the resultant pressure of this on health services. Obesity has been linked to an increased risk of heart disease, type 2 diabetes and some cancers. Excessive weight is blamed for 9,000 premature deaths a year in England and is estimated to reduce life expectancy by an average of nine years. The government calculates that obesity costs the NHS £1 billion a year, with a further economic cost of £2.3 billion to £2.6 billion.

Controversy

The government has unapologetically defined obesity as a symptom of ill health which should be eradicated. Attempting to manipulate individual's weight leaves the government vulnerable to accusations of "nanny statism".

The UK is yet to see the rise of a significant 'fat positive' movement. In the US a minority of obese people have hit out at attempts to medicalise and stigmatise their size and argue societies should accept people of all weights.

While most people accept that extreme fatness is not desirable, many are more resistant towards government attempts to enforce healthy lifestyles. At the extreme end this has seen parents feed burgers to their children through school gates after the government enforced new healthier school meals.

The public may resent government attempts to encourage healthy eating but the government has in turn been criticised for failing to promote or enable healthy lifestyles. Many point out it is inconsistent for ministers to lecture school children about healthy lunch choices while allowing the sale of school playing fields. Infrastructure such as cycle lanes is also poor in the UK compared to other European nations and many claim that private gyms remain prohibitively expensive.

A correlation can be observed between socio-economic status and obesity, although at least one recent study has found this is less pronounced among children. This has led many to interpret obesity as a symptom of health inequality. Although many commentators do note factors such as the price of gym membership, much of the blame for higher levels of obesity among poor people is placed on dietary choices.

Politicians and chefs are just some of those debating whether it really is cheaper to eat badly. In a bid to counter the assumption that junk food is more cost effective, ministers have been asked to consider the option of 'fat taxes' whereby a charge is levied against high fat, high salt or high sugar foods. This suggestion has proved incredibly unpopular with the public.

Despite the acceptance that too many calories and not enough activity will cause weight gain, scientists are still searching for a 'fat gene'. The diet industry has proved highly inefficient in the long-term, with most dieters either struggling to lose weight or putting it back on when lost. Nevertheless the government is determined the rising prevalence of obesity can be reversed.

How obesity is measured has also been criticised, with the BMI dismissed by some as an imperfect science. The BMI fails to distinguish between body fat and lean muscle, meaning professional athletes can emerge as overweight or even obese. Moreover, it fails to look at where fat is distributed on the body. It is now recognised that excess fat around the abdomen is a greater health risk than fat on the buttocks or thighs. For this reason, the World Health Organisation now recommends people measure their waists. A circumference over 37 inches (94 cm) on a man or 32 inches (80 cm) on a woman indicates a health risk.

Some have also questioned the assumption that excessive weight is a health risk. Obesity does broadly correlate to increased rates of a range of illnesses including diabetes and a number of cancers. However, a review of 7,000 studies by the World Cancer Research Fund found a third of cancers are attributable to diet and found at least six cancers for which obesity was a major risk factor.

However, it has been pointed out that these could also be caused by the lifestyle typically enjoyed by obese people, rather than the excess fat per se. It is, some argue, possible to be overweight and healthy. A recent study in the Journal of American Medical Association contradicted received wisdom by concluding extra weight could prolong life span.

Statistics

In 2005, 22 per cent of men and 24 per cent of women were obese.

By 2050 this is expected to increase to 60 per cent of men and 50 per cent of women.

18 per cent of boys and girls aged 2 to 15 years old are obese in England. In 1995, this was 11 per cent and 12 per cent respectively.

If one million people lost weight, 15,000 fewer people a year would develop coronary heart disease, 34,000 fewer people type 2 diabetes and 99,000 fewer people would develop high blood pressure.

26 per cent of men and 30 per cent of women eat at least five servings of fruit and vegetables a day. This has increased since 2001.

Statistics 1-3 & 5: (Source: Department of Health, 2007); statistic 4: (Source: National Audit Office, 2007).

Quotes

"Obesity is associated with many illnesses and is directly related to increased mortality and lower life expectancy. Tackling obesity is a government wide priority.

Department of Health, 2007.

"We are facing a potential crisis on the scale of climate change and it is in everybody's interest to turn things round. There is no single solution to tackle obesity and it cannot be tackled by government action alone."

Alan Johnson, secretary of state for health, 2007.