LINCOLN, Neb. — Fructose has gotten a bad rap in the obesity epidemic, says a University of Nebraska-Lincoln scientist whose research shows fat and other sugars are the primary culprits.
From 1970-2009, obesity rates in the United States increased from 13 percent of the population to 34 percent. Dietary fructose has been blamed as a possible contributor to this increase.
Nutrition scientist Tim Carr found that's not the case, though. While the total energy availability in Americans' food increased 10.7 percent over that period, consumption of fructose did not increase.
Carr based his findings on the U.S. Department of Agriculture's Loss-Adjusted Food Availability Database and its Nutrition Database for Standard Reference.
Those resources, rich in data about Americans' eating patterns over the years, show that the energy available from total glucose increased 13 percent. The main source of glucose in the American diet is starch. Also, glucose availability was more than three times that for fructose. Energy available from protein, carbohydrates and fat increased 4.7 percent, 9.8 percent and 14.6 percent, respectively.
"It is a misconception that fructose is a unique contributor to obesity," said Carr, who chairs UNL's Department of Nutrition and Health Sciences.
Some of that misconception may stem from the fact that the consumption of one type of fructose – high fructose corn syrup – has increased significantly over the last 40 years, but it has replaced another source of fructose – table sugar – leaving total consumption steady, Carr said.
"We're focusing the spotlight in the wrong place," Carr said. "Fructose turns out to be a relatively small contributor to the overall food supply."
In 1970, fructose availability was 63.2 grams per day. It has fluctuated in the years since, but stood at 62.4 grams in 2009.
"We conclude that increased total energy intake, due to increased availability of foods providing glucose (primarily as a starch in grains) and fat to be a significant contributor to increased obesity in the U.S." wrote Carr and graduate student Trevor Carden in an article outlining their findings in the December 2013 issue of Nutrition Journal, which can be found at http://go.unl.edu/bt40.
The research was supported by the University of Nebraska Agricultural Research Division with funds provided through the Hatch Act.