Tesco is putting the sticker on many of its products

The stickers will tell shoppers how products rate on the glycemic index.

This runs from zero to 100 and rates food in terms of how quickly it is digested and is converted to energy in the form of glucose.

The faster food is digested the sooner people will be hungry again. Generally, natural foods score low on the index while processed foods score highly.

For instance, cornflakes rate highly on the index because they provide people with a surge of energy but leave them hungry soon afterwards.

A bran cereal by comparison would have a much lower rating because it releases energy slowly and blunts appetite.

How foods rate Cornflakes 85 Branflakes 35 Tropical fruit 70 Peanuts 20 Baguette 80

Professor Jeya Henry of Oxford Brookes University said the labels could help people eat more healthily.

"It is predicated on good science," he told the BBC.

"Low glycemic food appears to all coincide with the type of healthy foods people should consume."

He added: "I think it could revolutionise our way of eating."

The labels are designed to help people who need to monitor their sugar intake, such as diabetics or athletes.

But it could also prove popular with those on low-carb, high protein diets.

The lower the rating on the glycemic index, the lower the number of carbohydrates.

The move comes just days after Tesco announced plans to use a traffic light system to rate food in terms of their fat content.

That followed a damning report from the Commons health committee on obesity. It urged the supermarkets and the food industry to do more to encourage people to eat more healthily.