New research has suggested that the "wrong kind" of sugar could be fuelling the obesity epidemic sweeping countries including the UK and the US.
Too much fructose may be harming people's health and helping to trigger diabetes, the study at America's University of California, found.
Pure fructose is found in fresh fruit and fruit juice. But much of it sneaks into the diet through high-fructose corn syrup, which is used in processed foods and soft drinks. It is also produced when sucrose, ordinary table sugar, is broken down in the body.
The study looked at the effect of fructose on 33 overweight and obese adults by putting them on a two-week diet of 30% fat, 55% complex carbohydrates, and 15% protein. For a further 10 weeks they were switched to a diet in which 25% of their energy came from either fructose or glucose.
In those given fructose, there was an increase in the amount of "pot belly" fat which wraps around internal organs and is linked to diabetes and heart disease. This did not happen to the group given sugar in the form of glucose, even though both gained an average 3.3lb (1.5kg) in weight, New Scientist magazine reported.