Featured Research

from universities, journals, and other organizations

Limiting Fructose May Boost Weight Loss, Researcher Reports

Date:
July 28, 2008
Source:
UT Southwestern Medical Center
Summary:
One of the reasons people on low-carbohydrate diets may lose weight is that they reduce their intake of fructose, a type of sugar that can be made into body fat quickly. Fructose is perhaps best known for its presence in the sweetener called high-fructose corn syrup or HFCS, which is typically 55 percent fructose and 45 percent glucose, similar to the mix that can be found in fruits.

New research supports health guidelines suggesting that limiting processed carbohydrates, many of which contain high-fructose corn syrup, may help prevent weight gain.
Credit: iStockphoto/Brian Toro

One of the reasons people on low-carbohydrate diets may lose weight is that they reduce their intake of fructose, a type of sugar that can be made into body fat quickly, according to a researcher at UT Southwestern Medical Center.

Dr. Elizabeth Parks, associate professor of clinical nutrition and lead author of a study appearing in a current issue of the Journal of Nutrition, said her team's findings suggest that the right type of carbohydrates a person eats may be just as important in weight control as the number of calories a person eats.

Current health guidelines suggest that limiting processed carbohydrates, many of which contain high-fructose corn syrup, may help prevent weight gain, and the new data on fructose clearly support this recommendation.

"Our study shows for the first time the surprising speed with which humans make body fat from fructose," Dr. Parks said. Fructose, glucose and sucrose, which is a mixture of fructose and glucose, are all forms of sugar but are metabolized differently.

"All three can be made into triglycerides, a form of body fat; however, once you start the process of fat synthesis from fructose, it's hard to slow it down," she said.

In humans, triglycerides are predominantly formed in the liver, which acts like a traffic cop to coordinate the use of dietary sugars. It is the liver's job, when it encounters glucose, to decide whether the body needs to store the glucose as glycogen, burn it for energy or turn the glucose into triglycerides. When there's a lot of glucose to process, it is put aside to process later.

Fructose, on the other hand, enters this metabolic pathway downstream, bypassing the traffic cop and flooding the metabolic pathway.

"It's basically sneaking into the rock concert through the fence," Dr. Parks said. "It's a less-controlled movement of fructose through these pathways that causes it to contribute to greater triglyceride synthesis. The bottom line of this study is that fructose very quickly gets made into fat in the body."

Though fructose, a monosaccharide, or simple sugar, is naturally found in high levels in fruit, it is also added to many processed foods. Fructose is perhaps best known for its presence in the sweetener called high-fructose corn syrup or HFCS, which is typically 55 percent fructose and 45 percent glucose, similar to the mix that can be found in fruits. It has become the preferred sweetener for many food manufacturers because it is generally cheaper, sweeter and easier to blend into beverages than table sugar.

For the study, six healthy individuals performed three different tests in which they had to consume a fruit drink formulation. In one test, the breakfast drink was 100 percent glucose, similar to the liquid doctors give patients to test for diabetes -- the oral glucose tolerance test. In the second test, they drank half glucose and half fructose, and in the third, they drank 25 percent glucose and 75 percent fructose. The tests were random and blinded, and the subjects ate a regular lunch about four hours later.

The researchers found that lipogenesis, the process by which sugars are turned into body fat, increased significantly when as little as half the glucose was replaced with fructose. Fructose given at breakfast also changed the way the body handled the food eaten at lunch. After fructose consumption, the liver increased the storage of lunch fats that might have been used for other purposes.

"The message from this study is powerful because body fat synthesis was measured immediately after the sweet drinks were consumed," Dr. Parks said. "The carbohydrates came into the body as sugars, the liver took the molecules apart like tinker toys, and put them back together to build fats. All this happened within four hours after the fructose drink. As a result, when the next meal was eaten, the lunch fat was more likely to be stored than burned.

"This is an underestimate of the effect of fructose because these individuals consumed the drinks while fasting and because the subjects were healthy, lean and could presumably process the fructose pretty quickly. Fat synthesis from sugars may be worse in people who are overweight or obese because this process may be already revved up."

Dr. Parks said that people trying to lose weight shouldn't eliminate fruit from their diets but that limiting processed foods containing the sugar may help.

"There are lots of people out there who want to demonize fructose as the cause of the obesity epidemic," she said. "I think it may be a contributor, but it's not the only problem. Americans are eating too many calories for their activity level. We're overeating fat, we're overeating protein; and we're overeating all sugars."

Some data were collected at the University of Minnesota, where Dr. Parks worked before joining the UT Southwestern faculty in 2006.

The work was supported by the National Institutes of Health, the Cargill Higher Education Fund and the Sugar Association.


Story Source:

The above story is based on materials provided by UT Southwestern Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

UT Southwestern Medical Center. "Limiting Fructose May Boost Weight Loss, Researcher Reports." ScienceDaily. ScienceDaily, 28 July 2008. <www.sciencedaily.com/releases/2008/07/080724064824.htm>.
UT Southwestern Medical Center. (2008, July 28). Limiting Fructose May Boost Weight Loss, Researcher Reports. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2008/07/080724064824.htm
UT Southwestern Medical Center. "Limiting Fructose May Boost Weight Loss, Researcher Reports." ScienceDaily. www.sciencedaily.com/releases/2008/07/080724064824.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins