Studies Indicate Fructose Not Responsible For Weight Gain
February 21, 2012

Studies Indicate Fructose Not Responsible For Weight Gain

According to a new study released this week, people who consumed a bit of extra fructose baked into breads or sprinkled into drinks did not gain additional weight compared to those who had other types of carbohydrates instead as long as they ate the same number of total calories.

However, when study participants supplemented a standard diet with a dash of extra calories in the form of straight fructose, they did gain weight, reports Reuters´ Genevra Pittman.

John Sievenpiper, MD, PhD, of McMaster University in Hamilton, Ontario, Canada is defending fructose from its bad reputation. The authors acknowledge, however, that many of the studies they reviewed had shortcomings and 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,” the researchers wrote.

Sievenpiper said this “represents pretty reasonable evidence that fructose in and of itself doesn´t contribute to weight gain. But when it contributes extra energy, that´s when you do see weight gain,” according to Pittman.

Researchers have wondered whether there´s something about fructose that makes people store fat and gain weight faster than other carbohydrates. This is a high concern as high-fructose corn syrup has become a primary ingredient in many common foods and drinks, especially sodas, writes Louise Chang, MD for WebMD.

Of the forty-one studies that were delved deeper into, thirty-one of them divided the participants into two groups. Each group consumed the same amount of calories overall, but one group consumed 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, however none was found.

The remaining ten 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.”

“Fructose may not be the villain,” says Cleveland Clinic´s Laura Jeffers, MEd, RD, LD, 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.”

The study is published in this week's addition of the Annals of Internal Medicine.


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