Fructose Off the Hook for Overweight and Obesity?
New Review Suggests Blaming Natural Sweetener Is Misguided
Feb. 20, 2012 -- When it comes to weight gain, fructose should not be singled out for blame, a new review of the scientific literature suggests.
The review, in the Annals of Internal Medicine, shows that excessive calories -- and not any unique properties of fructose -- are more likely to lead to extra pounds.
“Is fructose really the source of all metabolic evil?” says researcher John Sievenpiper, MD, PhD, of McMaster University in Hamilton, Ontario, Canada. “From our standpoint, it does not look like it is.”
However, the authors acknowledge that many of the studies they reviewed had serious shortcomings. Therefore, their conclusions are, in a word, inconclusive.
“Overall, the evidence from our analysis is too preliminary to guide food choices in the context of real-world intake patterns,” they write.
41 Studies Analyzed
The review drew upon a large number of studies, each of which falls into one of two types.
Thirty-one of the studies divided the participants into two groups. Each group consumed the same amount of calories, but one group ate fructose while those in the other group ate a different type of carbohydrate. Doing so allowed the researchers to isolate fructose in order to determine its effect on body weight change. They found none.
The remaining 10 studies under review were based around adding calories. In each, half of the participants ate their usual diet, while the other half added fructose, a naturally occurring sweetener, to what they normally ate. The fructose groups did gain weight, but no more than would be expected from the amount of additional calories -- or energy -- that they took in as part of the studies.
“Energy seems to be the dominant factor,” Sievenpiper says. “There was no effect from fructose.”
Number of Calories Is Key
The review is likely to be controversial because increased fructose consumption has been targeted as a leading cause of the obesity epidemic, particularly in the form of high fructose corn syrup, a sweetener added to non-diet soft drinks and many other food products. Sievenpiper, however, says the debate over fructose misses the point.
“We feel the controversy has directed the issue away from over-consumption. Our data suggests that fructose plays the same role as any energy-dense substance.”
Cleveland Clinic’s Laura Jeffers, MEd, RD, LD, agrees.
“Fructose may not be the villain,” says Jeffers, who reviewed the study for WebMD. “People should be aware of the total calories they’re consuming rather than worrying about one type of sugar.”
But do we need another study telling us that? No, says David Heber, MD, PhD, director of the UCLA Center for Human Nutrition.
“It’s much ado about nothing,” says Heber, who says that we should be focusing on how much fructose we consume and where we get it.
“There’s too much fructose in our diets, and it’s not coming from fruits and vegetables,” says Heber, who was not involved in the study. “If fructose comes from those things, I have no problem with it.”