Study: Dont Blame Obesity on Fructose

HAMILTON, OntarioFructose is unlikely to cause weight gain when substituted for other carbohydrates in diets with similar numbers of calories; however, fructose does increase weight gain in hypercaloric diets, according to a new study published in the Annals of Internal Medicine.

Researchers at McMaster University conducted a systematic literature review and meta-analysis of more than 40 published studies on whether the fructose molecule itself causes weight gain. Participants in the studies ate fructose in the form of free crystalline fructose, which was either baked into food or sprinkled on cereals or beverages. The studies did not look at high-fructose corn syrup.

In 31 "isocaloric" trials they reviewed, participants ate a similar number of calories, but one group ate pure fructose and the other ate non-fructose carbohydrates. The fructose group did not gain weight. In 10 "hypercaloric" trials, one group consumed their usual diet and the other added excess calories in the form of pure fructose to their usual diet or a control diet. Those who consumed the extra calories as fructose did gain weight.

The researchers said the findings could suggest that one calorie is simply the same as another, and when we consume too many calories we gain weight.

"Fructose does not seem to cause weight gain when it is substituted for other carbohydrates in diets providing similar calories," they said.

A review published last year in Critical Reviews in Food Science and Nutrition also found no evidence that ingestion of normal amounts of fructose is associated with an increase in food intake or body weight (compared to other carbohydrates), when it is not consumed in caloric excess. The findings support a similar review that analyzed the role of fructose on blood lipids, glucose, insulin and obesity among the healthy, normal weight population.