Should we take slimming pills?

Every doctor knows that losing weight and keeping weight off in the long term is hard work, and a lifelong battle for some. Hardly surprising, with one in four UK adults classed as obese, that 'miracle' slimming tablets are so widely advertised. But do they work - and are they safe?

Have you ever worried about your weight? Or wished you had a magic wand which would let you wake up tomorrow with the waist you had when you were a teenager? If so, you're in good company. Obesity is a huge (pardon the pun!) problem in the UK. Almost seven in 10 men and six in 10 women weigh more than the ideal range - you can find out what that means below. We're also getting fatter at a scary rate - the proportion of UK adults who are obese has doubled to one in four in the last 20 years.

Every doctor knows that losing weight and keeping weight off in the long term is hard work, and a lifelong battle for some. Hardly surprising, with such a big potential market, that 'miracle' slimming tablets are so widely advertised. But do they work - and are they safe?

How do doctors define being overweight?

Doctors use a formula of your weight and height to work out your body mass index, or BMI. A BMI of 18.5-25 is ideal; 25-30 is overweight; 30-40 is obese and over 40 is 'morbidly obese'. Your practice nurse can tell you what your BMI is. The higher your BMI is (above the ideal), the greater the risks to your health.

Does being overweight matter?

Sadly, there's no getting away from the risks to your health of being overweight. As well as increasing your risk of heart disease and diabetes, obesity raises your chances of arthritis and cancer.

It's natural to make excuses about your weight - to yourself and to others. One of the most common ones in my surgery is: 'I've got heavy bones'. Just last week I was testing out a state-of-the-art body analysis machine - just 5% of my weight comes from my bones! 'Glandular' or hormonal problems like an underactive thyroid gland can cause weight gain, but only about one in 100 overweight people has a hormonal problem, to account for it. Some medicines, including steroids, can make you more prone to weight gain. Sadly, the risks to your health are the same regardless of the cause, so it's still important to tackle it.


A medicine called orlistat is available on prescription. You can buy the same drug from your pharmacist, where it's sold as alli®. This medicine acts by reducing the amount of fat your body absorbs from your food (by just under a third). Overall, it has a good safety profile - the obvious side effect is that if you eat a very fatty meal and it isn't all absorbed from your bowel, the rest is going to go straight through you.

Orlistat certainly isn't an alternative to reducing the calories you eat and increasing the calories you burn with exercise. Some, but not all, people lose 10% or more of their body weight in six months while taking it. But you won't lose weight - and you certainly won't keep the weight off - if you just 'take the tablets'.

What about 'herbal remedies'?

Newspapers seem to be full of adverts for slimming teas, capsules, powders and potions. On the whole, the only thing that will get lighter if you buy them is your purse! Even more worryingly, some tablets sold over the internet can be dangerous to your health. Examples in recent years include tablets which contain amfetamine-like drugs. When you hear that these are closely related to the drug 'speed', taken by drug addicts, you get an idea of the risks. Some Chinese herbal remedies have also been shown to carry health risks.

Do fad diets work?

In a word, no - at least, rarely, and even more rarely in the long term. Recent research shows that it's the number of calories you eat, rather than how you get those calories (high protein, fat, carbohydrates, etc) that determines your weight gain.

So if fad diets and tablets don't work, what can I do?

Don't despair! There is good evidence that making even small changes to your lifestyle can add up to large benefits. Most importantly, if you can cement those changes into your daily pattern of living, the benefits will last a lifetime. All too many of us are 'yo-yo' dieters - we lose weight in the short term when we 'go on a diet', but it creeps back on the moment we 'come off' the diet.

The key is sustainability and working out what your personal needs are. I talk to my patients about the difference between 'going on a diet' and 'adopting a lifestyle'. We all get bored with dramatic restrictions to our lives, which may well be where so many of us fall down.

That's where the new MyHealth tool could be your secret weapon. It allows you to look at every aspect of your lifestyle and will put you in an imaginary queue of 100 people just like you. Your place in the queue helps you visualise your risk of heart attack or stroke as well as identifying what impact your lifestyle is having on your health.

But more than this, it helps you work out what your danger points are, and how you can tailor a plan to improve your health. If you're overweight, it will help show you how changes to your diet, exercise and alcohol intake can help cut your risk of heart attack and diabetes, as well as cutting your waistline. It could be the start of a whole new, revitalised you. So go on, what are you waiting for? Sign up to MyHealth today and take the first steps towards a difference that could last you a lifetime!

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.