Obesity

What is obesity?

In the UK an estimated 60.8 per cent of adults and 31.1 per cent of children are overweight. According to figures from 2009, almost a quarter of adults (22 per cent of men and 24 per cent of women) in England were classified as obese (BMI 30kg/m² or over).

Waist circumference is another important measure and 38 per cent of adults had a raised waist circumference in 2009 compared to 23 per cent in 1993.

Using both BMI and waist circumference to assess the risk of health problems, showed that in 2009:

• 19 per cent of men were estimated to be at increased risk
• 14 per cent at high risk
• 20 per cent at very high risk
• 14 per cent of women were at increased risk
• 18 per cent at high risk
• 23 per cent at very high risk

As many as 30,000 people die prematurely every year from obesity-related conditions.

Some experts believe obesity is responsible for more ill health than smoking. Being significantly overweight is linked to a wide range of health problems, including:

• Diabetes
• Heart disease
• High blood pressure
• Arthritis
• Indigestion
• Gallstones
• Some cancers (eg, breast and prostate cancers)
• Snoring and sleep apnoea
• Stress, anxiety, and depression
• Infertility

A study by the National Audit Office estimates 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.

Obesity causes

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-size portions.

However, the reality isn't as simple as that. A significant factor is that modern life is more sedentary than ever. A recent study showed that housewives in the 1950s ate more calories than their modern counterparts, but were significantly slimmer because their daily lives involved much more physical activity.

Diagnosing obesity

Most doctors calculate obesity using a formula known as the body mass index (BMI), which 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 your height in metres squared.

• 18.5 to 24.9 - normal
• 25 to 29.9 - overweight
• 30 and above - 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 BMIs of 25 and above.

BMI is not infallible. For instance, it is possible for a healthy, muscular athlete with very low levels of body fat to be classified obese using this formula.

Another way of assessing overweight and obesity is by measuring girth (waist circumference or, more importantly, waist to hip ratio). It's recognised that the central fat held in the abdomen is more dangerous than peripheral fat and acts as a toxic inflammatory organ. Waist to hip ratio is increasingly being used by doctors in preference to BMI as a better measurement of the risk of obesity and cardiovascular disease.

Obesity treatments

The best way to tackle obesity is by not putting on too much weight the first place. A combination of a healthy, balanced diet and regular exercise should be sufficient 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 are already obese, 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.

Surgery is usually only recommended for the most extreme cases, as it can be risky and patients require life-long monitoring for potential complications.

There are a number of surgical options, most of which reduce the size of the stomach, meaning that less food can be ingested and the person feels full quicker, and therefore eats less. A technique using an adjustable band around the top of the stomach has gained popularity, as it is a simpler and quicker than some other options. Recent research has shown that gastric band surgery can bring a rapid improvement in blood sugar control in those people whose obesity has lead to type 2 diabetes.