How labels on healthy food make you fatter

You've swapped chips for salad, cake for fruit and crisps for cereal bars - so why aren't you losing weight?

It's a question many frustrated dieters have puzzled over.

But now scientists may finally have the answer. They have found that if a food is labelled as a healthy option we tend to eat more of it - because we think it is less filling.

As a result we end up consuming more calories overall, undermining our saintly intentions.

People tend to binge when they see these healthy labels because they automatically assume they are making a better choice.

The research suggests that while eating unhealthily is often the cause of obesity, eating too much so-called "healthy" food could also make you put on weight.

The study is particularly relevant as many shoppers' food choices are guided by the "traffic light" system of labels. Foods with high levels of salt, sugar or fat are in labelled in red, while those with moderate levels are in yellow and low levels are in green.

But previous studies have claimed that food companies are not telling the truth about what their products contain, making it harder still to make an informed choice.

In this latest research, US scientists conducted three experiments - all of which showed that consumers believe that healthy foods are less filling than unhealthy foods.

In particular, when the food had a label which described it as healthy, the participants were more likely to eat more than they should.

In the first experiment, 50 volunteers were asked how they viewed the connection between the concepts of healthy and filling, while the second involved measuring the hunger levels of 40 people after eating a cookie that was described as either healthy or unhealthy.

In the third test, 72 participants were asked to order food before watching a short film. They had to evaluate how the presentation of the food affected the amount ordered. This was then compared to the amount of food they actually ate during the screening. The study, which was carried out by the University of Texas at Austin McCombs School of Business, said: "he findings suggest that the recent proliferation of healthy food labels may be ironically contributing to the obesity epidemic rather than reducing it."

However, if you believe your brain would never fall for such ploys, think again. A University of Birmingham study found that many shoppers experienced 'information overload' when looking at nutritional 'traffic light' labels. In one test, 40 per cent of people could not identify the healthier product.

- Daily Mail