Obesity is a major issue around the world, and as more and more people put on excess weight it is a problem that is only likely to get worse.
In the UK it is estimated that one in five men and a quarter of women are obese, and that as many as 30,000 people die prematurely every year from obesity-related conditions.
How do you know if you are obese?
Most doctors calculate obesity using a formula known as the Body Mass Index (BMI).
It is a measure based on height and weight that applies to both adult men and women.
To calculate your BMI divide your weight in kilograms by the square of your height in metres.
A BMI of 25 to 29.9 is considered overweight and one of 30 or above is considered obese.
Doctors have recently recognised a new category: those with a BMI above 40 are considered morbidly obese.
People with BMIs between 19 and 22 live longest. Death rates are noticeably higher for people with indexes 25 and above.
Underweight: less than 20
Normal weight: 20-25
Overweight: 25 – 29.9
Obese: over 30
Morbidly obese: over 40
Click to Calculate your BMI
The BMI is not infallible. For instance, it is possible for a healthy, muscular athlete with very low body fat to be classified obese using the BMI formula.
Why is obesity a problem?
Experts believe that obesity is responsible for more ill health even than smoking.
Being significantly overweight is linked to a wide range of health problems, including:
* Heart disease.
* High blood pressure.
* Some cancers (e.g. breast, prostate).
* Snoring and sleep apnoea. Stress, anxiety, and depression
What is the wider impact of obesity?
A study by the National Audit Office has estimated that obesity costs the NHS at least £500m a year – and the wider economy more than £2bn a year in lost productivity.
The problem is growing rapidly. Experts predict that if the current rate of growth continues, three-quarters of the population could suffer the ill effects of excess weight within 10 to 15 years.
Why is obesity on the increase?
It would be tempting to suggest that more people are seriously overweight than ever before because they eat too much.
Certainly, experts are worried about the high fat and sugar levels in many convenience and mass-produced foods. There is also concern about the advent of ‘super-sized’ portions, already popular in the US.
However, the reality is not as simple as that. A significant factor is that modern life is more sedentary than ever before.
A recent study showed that housewives in the 1950s actually ate more calories than their modern counterparts – but they were significantly slimmer because their daily lives involved far more physical activity.
What action do campaigners want?
The government has been accused of failing to implement “joined up thinking” in tackling obesity.
It has been criticised for focussing on cars in its transport policy, rather than advocating the healthier options of walking and cycling.
Parents have called for vending machines selling crisps and chocolate to be taken out of schools.
The government has also been urged to do more to persuade the food industry to promote healthy foods to consumers.
What is actually being done?
The government is due to publish a public health White Paper in the summer which will look at what can be done to tackle obesity.
It has already published consultation papers on diet and exercise in schools, how employers could help workers get fit and how manufacturers can reduce fat, sugar and salt in food, which will inform the White Paper.
Measures such as a ban on junk food ads to children are also being considered.
The Chief Medical Officer also published a report urging people to exercise five times a week in order to stay healthy.
How can you tackle obesity?
The best way to tackle the problem is by not getting fat in the first place. A combination of a healthy, balanced diet, and regular exercise should do the trick in most instances.
Experts recommend vigorous exercise such as brisk walking, swimming or cycling five times a week for 20-30 minutes.
For those who have been unable to avoid piling on the pounds, weight management clinics are available to provide expert help and advice.
In severe cases doctors may prescribe drug therapies, which have been shown to have some positive impact.
Among these are orlistat (brand name Xenical), which works by blocking the digestion of fat.
Another drug which has produced promising results is sibutramine (Reductil), which works by boosting the signal to stop eating so that patients feel fuller sooner and eat less.
Is surgery an option?
Yes, but it is usually only recommended for the most extreme cases, as the surgery itself can be risky, and the patients require lifelong monitoring for potential complications.
Two types of surgery are in use:
* Roux-en-Y: Staples or bands are used to make the stomach smaller and allow food to bypass part of the small intestine where many nutrients are absorbed.
* Extensive gastric bypass: A more complicated procedure, in which the lower portion of the stomach is bypassed. The small pouch that remains is connected directly to the final segment of the small intestine.
In theory both operations are reversible, but this can be difficult. Reversal is almost always accompanied by rapid regain of body weight.
An alternative is to wire up the jaw to prevent people chewing food. This can help people lose weight, but many doctors are concerned about the psychological impact. It also does little to encourage healthy eating.