Many health claims made for popular foods will have to be watered down or ditched altogether as a result of new European legislation, experts have warned.

Full implementation of the European Nutrition and Health Claims Regulation, which will control the claims that can be made for foods on packaging, is still about three years away.

But the process of getting claims approved is already under way - and there are warnings that some companies will struggle to gain approval, and may have to depend on consumer awareness to drive sales.

The FSA is currently accepting applications for claims approval from manufacturers, which must be backed by scientific evidence.

It will analyse these before deciding which deserve to be passed to the European Food Safety Authority, where they will be scrutinised again. Only if they gain EFSA approval will claims be permitted, though claims can continue to be made until that decision is made. The FSA has provided guidance on the kind of information it requires to support claims, which includes studies published in "reputable peer reviewed journals."

But supplying this kind of information will not be straightforward.

"Some claims are based on just two or three studies, which have involved testing products on small groups, and just won't be robust," said Stephanie French, MD of nutrition consultancy Harlequin Plus.

Major food companies are reluctant to discuss the new regulation in detail.

Just one supplier we contacted agreed to be interviewed - Unilever, which is to withdraw its Flora Pro-activ blood pressure controlling product as a result of poor sales linked to a lack of scientific evidence.

"We expected the balance of scientific evidence to move on, but that has not happened," said a spokesman. "The burden of proof to support claims will be much heavier on all suppliers."

The new rules will mean no company will be able to avoid addressing whether or not they have the evidence to back claims, said Ed Komorowski, technical director at trade body Dairy UK.

"Today there may well be products on the market for which claims cannot be backed up. Companies will have to think carefully about whether they can justify them. And it will be done for them by this process."claims under the spotlight

Claims that are likely to fall under the gaze of the new legislation include that made by Cereal Partners, which claims Nestlé wholegrain cereals have a prebiotic effect.

This is backed up on-pack by a single study by the University of Reading.

Danone, meanwhile, also cites just one study on its website to support claims its Shape Lasting Satisfaction yoghurt increases a feeling of satiety.

The Grocer was unable to establish if further evidence existed to support these claims - or whether any work is under way to generate it.