Can pills really help us lose weight?

The launch in pharmacies of the slimming drug Alli in the UK has led to a rise in people convinced a pill could be the answer to their weight issues. The drug works by preventing absorption of fat by the body, and the makers claim it can boost weight loss for those dieting by an extra 50 per cent. Users, though, are already reporting some unpleasant side effects – the drug causes wind and diarrhoea in those who eat to much fat. While this may encourage users to eat less fat, it means they're also likely simply to stop taking the drug.

But with many overweight people looking for a more natural way to shift the weight easily, just how effective are the alternatives on offer? Professor Nick Finer, consultant endocrinologist at University College London, is blunt in his opinion of non-licensed "weight loss pills": "I think they're a waste of money as there's no high level evidence that they are effective."

Zotrim

Its makers claim it is a "natural alternative" to chemical slimming pills. Made from stimulating and invigorating ingredients yerba mate, guarana and damiana, the pills need to be taken before each meal to make users feel fuller more quickly and have more energy, thus burning off more calories. A test involving 47 overweight subjects showed that when they took Zotrim they lost an average of 5.1 kg over 45 days, the manufacturers say. Professor Finer comments: "As far as I'm aware, there have been no convincing, controlled trials that show that the very small amount of these chemical compounds which derive from herbal products have any effect at all."

Appesat

This is another product on the market that takes its active ingredient from a "natural" source – seaweed. Its makers say the ingredients work as a natural appetite suppressant, stimulating sensors in the stomach wall that indicate to the brain that the stomach is full. Professor Finer says: "There's no such thing as a 'natural' drug – they're all chemicals. If anybody is producing something that's natural, herbal, chemical, mystical or magical and if it is being positioned as a treatment for overweight or obesity then it has to have a license, otherwise it isn't a treatment."

Adios

The "UK's number one selling slimming tablet", according to its website – is a herbal formula made up of fucus dry extract (otherwise known as Bladder Wrack seaweed) boldo dry extract (a Chilean tree leaf) and butternut (a white walnut tree). The makers say it speeds up the body's metabolic rate and stimulates fat metabolism. "Products like this contain very small amounts of compounds which, in much larger doses, can have effects on metabolic rate and appetite, but are unlikely to do so in lower doses," comments Professor Finer.