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.


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 at current rates 90 per cent of adults will be overweight or obese. 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.

Recent surveys found that just a third of men and a quarter of women claimed to achieve the recommended 30 minutes of exercise five times a week. Half of those not taking part claimed their health was not good enough to exercise and nearly one in five said they did 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 has been blamed for 9,000 premature deaths a year in England and calculated to reduce life expectancy by an average of nine years.  According to the Department of Health, direct costs caused by obesity are estimated to be £4.2 billion per year and forecast to more than double by 2050 "if we carry on as we are."

In January 2008 the Government published 'Healthy Weight, Healthy Lives: A cross-government strategy for England', described as "the first step in a sustained programme to combat obesity and support people to maintain a healthy weight." A sum of £372 million over three years was committed to implement the strategy which focused on five key areas: -

The healthy growth and development of children; promoting healthier food choices; building physical activity into our lives; creating incentives for better health; and personalised advice and support.

A follow-up report published in March 2010 showed that although "good progress" had been made, there was still "more to do." Child obesity in the under-11s was levelling off but prevalence remained high and adult and teenage levels were still too high.

The 2008 initiative was followed by two further campaigns. In January 2010, 'Start4Life' was launched with the aim of helping frontline staff deliver the Healthy Child Programme, supporting pregnant women and the parents of 0-2 year olds in establishing good feeding and activity habits for babies, to help reduce the risk of obesity in later life.

This was followed in February 2010 by the 'Change4Life' campaign for adults, which focused on the 45-65 age group and provided guidance and support on how to achieve a healthy weight and prevent the onset of weight-related illness.

The Government continued to invest in the Change4Life campaign and in October 2011 published a Change4Life three year social marketing strategy for 2011-14.

Alongside this, the Government also published 'Healthy Lives, Healthy People: A call to action on obesity in England'. This report set out "a new focus and a new level of ambition" in tackling the problems of overweight and obesity.


The government has unapologetically defined obesity as a symptom of ill health which should be eradicated. Attempting to manipulate the weight of individuals 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. 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.

Nevertheless, the Coalition government remains committed to reducing levels of obesity and overweight in both children and adults.

The Public Health Responsibility Deal launched in 2011 aims to tap into the potential for businesses and influential organisations to improve public health.  Organisations signing up to the Deal make specific commitments which include such things as food pledges on calorie reduction and calorie labelling on menus.

The Government has also set two new national ambitions "to act as a 'rallying cry' for us all and show what might be achieved if we all pull together."  These are -

a sustained downward trend in the level of excess weight in children by 2020 and

a downward trend in the level of excess weight averaged across all adults by 2020.


A total of 23% of adults are obese ( with a body mass index (BMI) of over 30
61.3% are either overweight or obese ( with a BMI of over 25)
For children, 23.1% of 4-5 year olds are overweight or obese and 33.3% of 10-11 year olds.

Source: DoH - October 2011 -

Being obese or overweight brings significant risks at a range of different points throughout life. The health risks for adults are stark.

We know that, compared with a healthy weight man, an obese man is:

five times more likely to develop type 2 diabetes
three times more likely to develop cancer of the colon
more than two and a half times more likely to develop high blood pressure – a major risk factor for stroke and heart disease

An obese woman, compared with a healthy weight woman, is:

almost 13 times more likely to develop type 2 diabetes
more than four times more likely to develop high blood pressure
more than three times more likely to have a heart attack

Source: DoH - 2012


"To tackle overweight and obesity effectively we need to adopt a life course approach – from pre-conception, through pregnancy, infancy, early years, childhood, adolescence and teenage years, and through to adulthood and preparing for older age."

DoH: 'Healthy lives, healthy people'  report – October 2011

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