Millions being tricked into buying useless diet food products or supplements

Globally every year, obese people waste billions of pounds on food products that 'imply' that they aid weight loss, but are totally ineffective, says a nutritional expert on bmj.com.

Professor Lean from the University of Glasgow, is hopeful that a new European Union (EU) Directive on Unfair Commercial Practices, adopted this year in UK, will finally protect vulnerable consumers who are tricked into to buying useless food products or supplements in attempts to combat their disease.

Unlike medicines, food products that are marketed for health reasons are not subject to the same stringent research trials and control, and consumers are often misled.

It is already illegal for unsubstantiated claims to be made about the composition or nutritional function of food products, eg. that they are low in fat, high in fibre or help lower cholesterol, and it is also illegal to claim that a food can treat or prevent any disease—including obesity. However, many unsubstantiated health claims are still made, or implied. Misleading marketing can be found within brand names and images on packaging, in shelf or shop names, or on websites which suggest that products help weight control, are slimming, or are "Health Foods", when there is no evidence.

Lean is concerned that obese people have been fooled into parting with billions of pounds every year on products that cannot help them. In 2000, people in the US spent $35bn (£22bn) on weight loss products, many of them making false and unsubstantiated claims.

The "commercial exploitation of vulnerable patients with quack medicines" will hopefully be brought to an end with the introduction of the new EU directive, say Lean. However, the laws need to be enforced proactively to enable doctors and consumers to move towards managing diseases confidently with evidence based treatment and diet programmes.

He points out that, of all the hundreds of products currently on sale to help people lose weight, only energy-restricted diets and exercise, the drugs orlistat and sibutramine, and in some cases bariatric surgery, are safe, effective and cost-effective. The remainder, he says, are either not effective or not safe.

The new regulations "may even help with the bigger battle to prevent obesity, by prohibiting advertisements across the EU that encourage children to buy energy dense products or to pester their parents to buy them", he adds.