02 December 2015 00:02:06

Obesity: how can fat affect health?

The UK has one of the fastest growing rates of obesity in the world and one in four adults in Britain is now obese. But does it matter for our health and if so, what can we do about it?

The UK has one of the fastest growing rates of obesity in the world and one in four adults in Britain is now obese. But does it matter for our health and if so, what can we do about it?

The World Health Organisation describes it as a ‘global epidemic’ – they’re talking about obesity, not malaria or influenza. People are getting fatter all around the world, but the UK has a particular issue. Rates of obesity here have almost tripled since 1980, and being overweight is now the norm – over two thirds of men and over half of women are now overweight or obese. We must start educating about weight early – reports in the media this week highlighted the fact that 1 in 10 children starting primary school is obese, but by the time they leave primary school that figure is up to 1 in 5. What’s more, children in the most deprived areas are almost twice as likely to be obese as those living in affluent areas.

Obesity is measured in the UK using BMI, or Body Mass Index. It’s a formula comparing your weight to your height. A BMI of 19-25 is ‘ideal’, 25-30 is overweight, over 30 is obese. It has its flaws, but for most people it’s a pretty good measure of the weight you should be aiming for. The risk of getting several medical conditions rises in the overweight category and skyrockets for obese people. There has been lots of debate in recent years about whether BMI is the best indicator of obesity – but while it may not be perfect, for whole populations it’s a pretty good indicator, and easier to do than other measurements like hip:waist ratios .

Among the biggest risks are heart disease and stroke. It’s estimated the NHS spends £127 million a year on treating heart disease directly down to excess weight – and that’s without taking the suffering and cost to society into account. Being overweight makes you prone to high blood pressure and raised cholesterol.

Type 2 diabetes (about 90% of Britons with diabetes have type 2) is another health concern. It can run in families and it’s more common in people of South Asian origin. But the biggest single risk factor for type 2 diabetes is obesity. In terms of what causes it, it’s completely different to type 1 diabetes, which has nothing to do with weight.

Type 2 diabetes is a huge and growing issue in the UK. About 3.2 million people in the UK have type 2 diabetes, although about half a million haven’t yet been diagnosed with it. That’s an increase of over a third in the last decade. If things keep going as they are, it’s estimated that 4 million people in the UK will have diabetes in a decade, and by 2030 one in seven adults could have diabetes in some areas.

On the plus side if you’re overweight, losing just a few pounds of weight and keeping it off can make a real positive difference to your health. It reduces the strain your joints are under and can relieve symptoms of arthritis. It cuts blood pressure, cholesterol and your risk of some cancers. Every little helps - losing 10 kg of weight cuts your risk of dying from some cancers by a spectacular 40%.

The best way to lose weight is slowly – one to two pounds a week. Crash diets may work in the short term, but you’re more likely to put the weight on again. That’s because keeping the weight off involves learning new patterns of eating to avoid the habits that caused the weight gain in the first place. Don’t forget alcohol when you’re doing your calculations – pure alcohol has nearly as many calories as pure fat. And of course regular exercise will help. Sugary foods are completely ‘empty’ calories, with no nutritional benefits whatsoever – and sugary drinks in particular are very efficient at getting calories into your body very quickly!

Commercial slimming organisations can be hugely effective, or your practice nurse can give advice. In some areas, exercise classes or even gym membership are available ‘on prescription’ – speak to your GP. If you’re very obese, weight loss surgery with gastric bypass or banding may be considered, but this is usually a last resort.

Many medicines for weight loss have been manufactured over the years – losing weight isn’t easy, and many people are tempted by a quick fix. But of the three available on prescription in the UK in the last 10 years, two have been taken off the market because of health concerns. Only one, Orlistat - sold in pharmacies as Alli® - reduces the amount of fat you absorb from your diet . It can help with weight loss but the side effects can be embarrassing (think about it – if you eat fatty food and it’s not absorbed into your system, it has to come out the other end…).

With thanks to ‘My Weekly’ magazine where this article was originally published.

Dr Sarah is unable to provide medical advice or respond directly to questions concerning your health. If you have health concerns we recommend contacting your GP.