Fructose not linked to extra weight gain: report

A little extra simple sugar in your diet probably won't make you pack on the pounds - as long as you cut down on other carbs to make up for it, a new analysis of past studies suggests.

Researchers found that people who consumed extra fructose baked into breads or sprinkled into drinks didn't gain any extra weight compared to those who had other types of carbohydrates instead - when they ate the same number of total calories.

On the other hand, when study participants supplemented a standard diet with extra calories in the form of straight fructose, they did gain weight.

"Fructose probably isn't any different than other sources of carbohydrates," said lead author Dr. John Sievenpiper, a research fellow at St. Michael's Hospital in Toronto.

The finding, he told Reuters Health, "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."

Researchers have wondered whether there's something about fructose - typically found in fruits as well as baked goods and sugar-sweetened beverages - that makes people store fat and gain weight faster than other carbohydrates.

In an attempt to explain the ever-increasing (no pun intended) incidence of obesity in the U.S., fingers have been pointing of late to fructose. It's a sweetener found naturally in fruit and honey and as a component of high-fructose corn syrup, which is used in sweetened foods and beverages.

Some research has suggested that fructose may stimulate a hormonal response in the body that promotes weight gain. Other studies have hypothesized that fructose, vs. other forms of sugar, may trick you into thinking you are hungrier than you should be. But is fructose the real culprit? Many experts don't think so.

"I believe recent allegations suggesting that fructose is uniquely responsible for the current obesity crisis in the U.S. are unfounded," says biochemist John S. White, PhD, a researcher and consultant who specializes in nutritive sweeteners. "These allegations - such as increased fat production or increased appetite - are based on poorly conceived experimentation of little relevance to the human diet, which tests unphysiologically high levels of fructose as the sole carbohydrate, often in animals that are poor models for human metabolism."

Even the FDA, says White, has concluded that "high-fructose corn syrup is as safe for use in food as sucrose, corn sugar, corn syrup, and invert sugar."

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by Louise Chang, MD

That's especially a concern because high-fructose corn syrup is a main ingredient in many common foods and drinks, including soda.

To see where the evidence stands, Sievenpiper and his colleagues looked back at studies that compared weight gain in people assigned to eat diets high in fructose or another carbohydrate instead, most commonly starch or glucose.