Limiting Fructose May Boost Weight Loss
July 24, 2008
Digg This! | Send to Newsvine | Add to del.icio.usJuly 24, 2008 (Newswise) — 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.
Visit http://www.utsouthwestern.org/nutrition to learn more about clinical services in nutrition at UT Southwestern.
Dr. Elizabeth Parks -- http://www.utsouthwestern.edu/findfac/professional/0,2356,78859,00.html
Posted by dlifenews at July 24, 2008 10:54 AM
Comments
I only use Sweet N Low. This has dextrose! Is this causing my weight gain? I walk for 30 minutes a day! I have been a diabetic for 52 years and this is the first time i've gained weight!
Posted by: Denise at August 5, 2008 02:27 PM
I know that I have found whenever eating the "sugar free" candies that the statement- may have a lax.effect- certainly is a true one- I do have to limit and be very carefull.Mb
Posted by: marybob at August 4, 2008 09:08 PM
arnolds whole wheat bread no hfc its great i get it at walmart
Posted by: james helm at August 1, 2008 11:21 PM
I write for dLIFE.com...and have written about fructose on and off over the past 30-some years. It's important to clarify something here. Fruit contains small amounts of fructose -- in general not enough to pose a problem (but important to track if you are carefully watching carbs or exchanges). Fruit also has fiber, which slows the absorption of sugars and starches. Nonstarchy, high-fiber fruits contain even less, and these would include raspberries, blueberries, blackberries, and kiwifruit. (Frozen berries are just as good, nutritionally, as fresh, and frozen are generally cheaper and available all year long.)
The bigger problem is fructose that's added to packaged foods. Most often, it's in the form of "high-fructose corn syrup," which is a blend of glucose and fructose, but it may also be listed as corn syrup. All of these little bits (and not so little bits) of high-fructose corn syrup add up.
The easiest way to avoid this stuff is to avoid packaged foods (boxes, cans, bottles, jars) or to read label ingredients very carefully. This often means cooking food from scratch...which isn't that difficult and doesn't take that much extra time...but yields a big payoff in terms of health benefits.
I hope this clarifies things a little. Nonstarchy fruit is good, but added high-fructose corn syrup is not.
Posted by: Jack%20Challem at August 1, 2008 04:34 PM
I have been told that fructose has a much lower GI rating than cane sugar, so would be a better alternative than aspartame and other synthetic sweeteners which are carcinogenic or can lead to alzheimer's. Is this true??
Posted by: Vivian at July 31, 2008 04:06 AM
Good to learn that someone besides me is on to high fructos corn syrup. Nearly everything you try to buy has this garbage in it even whole grain breads.
Posted by: Joan Holbert at July 30, 2008 08:06 PM
I drink a lot of tea (weak, not strong). For years I've been using granulated fructose to sweeten it in the pitcher. I don't like to use Equal, Splenda, or Sweet N Low, because it usually comes in packets and the ones that do come in bigger packages costs too much and have to use a lot of it. If I don't put sugar in my tea, I get diahrrea. And one of the other lady's comments said she had seizures when she used Equal and Splenda, assuming she has epilipsy in the family as do I. Would it be better if I just used regular sugar? So which would be better for me to use? I'm so confused.
Posted by: Kathleen at July 30, 2008 06:42 PM
I don't understand the compartmental thinking: fructose from fruit is "good," but fructose added to processed food is "bad." The body does not know what the source of the fructose is...it's just fructose, and will deal with it the exact same way.
There is no reason to eat fruit. Low carb vegetables have just as much nutrients as fruit, but without the added post prandial sugar load that fruit causes. It is not logical to eat a food substance that causes elevated PP sugar spikes for the sake of the small amount of antioxidants and fiber that can also be obtained in vegetables that do not cause elevated PP blood sugar spikes.
Posted by: Georgette at July 30, 2008 02:45 PM
I am glad to hear of someone else using exercise as med. I have only used strict diet and exercise as my only meds and am constantly told that it is not possible. I have my A1c down to 5.9 and glucose is at 98. It was very hard for a long time but now it is as natural as breathing. Best Wishes!
Posted by: Anita%20Davis at July 30, 2008 11:44 AM
which fruits & veggies have high fructose values? Could you send me a chart? Thanks
Posted by: DON at July 29, 2008 10:38 PM
Hi everyone,
I'm the food & nutrition editor here at dLife, and thought I'd pop in and answer a couple of your questions.
First, the artificial sweeteners Splenda and Equal (yellow and blue packets, respectively) do not contain fructose. Fructose is a sugar, and Splenda and Equal are sugar substitutes.
Lean Cuisine meals are not likely to contain high fructose corn syrup, but you should always read labels of any foods that come in a package.
And as this researcher says, don't worry for a minute about fresh fruit (unless you're counting carbs; then just count them!). Fresh fruit is not what's making America fat.
This research is just more support for eating whole foods rather than processed, packaged products -- which are, yes, highly likely to include the ubiquitous sweetener, high fructose corn syrup.
Hope that helps!
Lynn
******************************
Lynn Prowitt-Smith
dLife Food & Nutrition Editor
Posted by: Lynn at July 29, 2008 06:53 PM
Last X-mas, I received See's Sugarfree peanut brittle for a gift. I got really sick from it.
Be careful and read the ingredients!!!!
Good luck
Posted by: Rita at July 29, 2008 05:01 PM
High fructose corn syrup is, indeed hidden in almost everything we buy, including ketchup, salad dressings, breads, almost all baked goods (which are also steeped in hydrogenated fats) soups, cereals, you name it. It's imperative for a diabetic, or borderline one such as myself, to read the labels. I avoid processed foods, white anything, except the occasional piece of restaurant pizza & a good N.Y. bagel! It's easy to "process" your own "fast foods" using whole grains, fresh fruits in season & home grown vegetables, if you can grow your own. I press my freezer into use lots, & try to control portion size. I'm angry that our food supply is so adulterated with these cheap additives to stretch the profits at the expense of the American public's health. Things won't change until we yell hard & loud & often at the powers that be who oversee (yeah, right!) our food industry, & I'm not sure enough of us really even care anymore.
Posted by: Della H at July 29, 2008 04:56 PM
What about splenda?
Posted by: Camille Loyd at July 29, 2008 04:03 PM
just buy whole food, not man-made GMO crap, getting hard to find USA grown stuff also.
Posted by: Roaminghermit at July 29, 2008 03:20 PM
I have been a type2 diabetic since Feb 1982 since
then I have been riding an exercise bike 3 times
a day,and walking 3 times a day when it is'nt too
hot. I have had both knees operated on and now I
have a bad back, and walk with a cane,but I still
do it. I'am 73 years old, I also have to watch all
the ingredients for high fructose I also use splenda, because i had used equal for many years
and had seizures for over 10 years and the Doctors
said anxiety ,never even checking it out, when
splenda came on the market,and I started using it,
after the other got out of my system, I quit
having the seizures,then when I used products with
that in it I started having them all over.
My sugar readings have all been in normal range now foe quit a while. My a1c is 6.0 my Doctor is
very pleased.
Posted by: Virginia L. Pershing at July 29, 2008 02:31 PM
This news is somewhat frustrating. I've pretty much given up most of the starch in my diet. I've replaced it with plenty of fresh fruit and vegetables. What do I do now?
Posted by: Steve at July 29, 2008 01:10 PM
Foods with fructose as one the main additives has always puzzled me. Everything is made with sugar, HFCS, or someother sweetner what's a body to do.
Posted by: Big Dread at July 29, 2008 01:09 PM
High fructose corn syrup is added to SO MANY prepared foods. Two of the biggest culprits are bread and ketchup. Even breads that are advertised as "whole-grain", "organic" or "natural" can have HFCS as the second ingredient. Be sure to read the ingredients on all prepared foods. I know for myself, HFCS makes my blood sugar soar. My children are not diabetic, but I will not let them eat it either. Too much chemistry and manufacturing in food is not a good thing!
Posted by: Lisa at July 29, 2008 11:48 AM
Can you name some food high in these sugars? I eat quite a few lean crusines are they okay? I try to stay as far away from sugar as I can but it seems to be in everthing. Im also using splenda for sweeting. Is that okay?
Posted by: diane at July 29, 2008 11:20 AM
Is Equal, the blue packet sweetner, primarily fructose? This article substantiates a belief I already hold that a calorie is not a calorie to a diabetic...!!
Posted by: Catherine Schuller at July 29, 2008 11:07 AM
The best way to take advantage of the health value of fructose is to eat fresh fruits. Processed foods containing high fructose corn syrup, per my understanding, are not half as good as fresh fruits as source of fructose and food nutrients.
For more than 17 years as a type 2 diabetic using exercise as my only diabetes medication and eating plenty of fresh fruits every day, I have always been skinny, healthy, strong, and feeling younger than my actual age. I am now 72 1/2 and doing very very well. To me fresh fruits (fructose) are very important, useful, and necessary healthy food for me.
Posted by: Bonny C Damocles at July 29, 2008 10:43 AM
I always look at ingredients on packages and cans. Years ago I stopped drinking sodas because of high fructose and when I got tired of eating oatmeal I looked at all the cereals and most of them are high fructose. I finally settled for Life Cereal. Yes, it is very hard to lose weight especially when you have a bad knee sometimes and can't do your exercises. Ha Ha Thanks
Posted by: Dot at July 29, 2008 10:36 AM