Dieters smugly snacking away on "low-fat" or "fat-free" treats may be unwittingly piling on weight, rather than fighting flab, because of misleading food labels.
New research has found that some foods popular with weight-watchers may contain more fat than the non-dietary alternative products.
While "low-fat" drinks, "85 per cent fat-free" cakes and "half the fat of normal chocolate" bars provided solace to those watching their waistlines, researchers believe they may have been doing more harm than good.
A standard Tesco strawberry cheesecake was found to have less fat than a "85 per cent fat free" caramel biscuit on a shelf in the same store, according to Which? magazine.
"A product which is `95 per cent fat free' may in fact contain a huge proportion of fat," said a Consumers' Association of Ireland (CAI) food science researcher, Ms Celine Murrin.
The problem in Ireland stems from current food-labelling legislation, which does not specify how much fat a product has to contain to use labels such as "low-fat".
"Nutritional claims on products are deceiving consumers," Ms Murrin said. "This is a really serious problem."
The CAI is investigating a number of complaints about misleading claims made by manufacturers of food products.
Ms Murrin said the claims by manufacturers needed to be made clear and she called for regulations to set standards for food labels in Ireland.
Food-labelling is the responsibility of the Department of Enterprise and Employment. A Department spokesman said nutritional information on labels was a "grey area" for the Government.
"We would urge the European Commission to introduce measures to tackle this problem," he said, adding any labelling directives had to be issued by the Commission.
A previous effort by the Commission to introduce a directive to set a standard for food-labelling claims failed in 1993.
In addition to regulating claims about the fat content of foods, it also intended to set out what could be called natural, pure or fresh.
The British government now intends to put the issue back on the agenda by introducing its own national fat-labelling guidelines.
British ministers are also pressing the European Commission to do likewise on an EU-wide basis.
Under the British guidelines, any food labelled "low-fat" must contain less than three grammes of fat per 100 grammes. "Low-saturate" foods will have to have less than 1.5 grammes per 100 grammes.
All firms will have 18 months to comply with the new regulations.