Reduced-Glycemic-Load Diet Sheds Pounds, Lowers Diabetes Risk

By  Jennifer Warner 

Reviewed By Michael Smith, MD
on Tuesday, August 12, 2003
WebMD Medical News

Aug. 12, 2003 -- A diet that focuses on changing how and what a child
eats rather than just counting calories and fat grams may help obese
children and adolescents lose weight and lower their risk of
developing type 2 diabetes.

New research shows a reduced-glycemic-load diet that emphasizes foods
with a low to moderate glycemic index and allows children to eat until
they're full was more effective than a traditional low-fat,
calorie-restricted diet in helping obese children shed pounds and
slow the progression of insulin resistance, a risk factor for diabetes.

Foods with a high glycemic index include simple carbohydrates, such
as white bread, white rice, sweet cereals, and sugary foods.
Researchers say these foods cause blood sugar levels to surge after
eating, which places additional stress on the cells in the pancreas
that produce the insulin needed to process sugar in the body.

Complex carbohydrates, such as whole-grain bread and cereals, brown
rice, and vegetables, are foods with a low to moderate glycemic
index.

By preventing this surge in blood sugar associated with eating foods
with a high glycemic index, previous research suggests that people
can curb their carbohydrate cravings and reduce their risk of
diabetes.

Researchers say it's the first time the benefits of targeting the
composition of a child's diet rather than just the total calorie
intake have been shown in a major scientific study. The results
appear in the current issue of Archives of Pediatric & Adolescent
Medicine

"I think it is the first well-controlled study to show that we need
to look at the composition [of the diet]. It's not a calorie is a
calorie is a calorie," says Melinda Sothern, PhD, director of the
Prevention of Childhood Obesity Laboratory at Louisiana State
University's Pennington Biomedical Research Center. "It's echoing
what we're seeing in the adult literature."

Counting Carbs vs. Calories

In this study, researchers compared the effects of the following two
diets in a group of 14 obese adolescents between the ages of 13 and
21:

A reduced-glycemic-load diet that emphasized eating foods with a low
to moderate glycemic index and getting 45% to 50% of their daily
calories from complex carbohydrates, such as whole grains, fruits,
and vegetables, and 30% to 35% from fat
A conventional reduced-fat diet that emphasized eating foods low in
fat with 55% to 60% of daily calories from carbohydrates and 25% to
30% from fat

After one year, adolescents who followed the reduced-glycemic-load
diet lost an average of 11 pounds more than those on the conventional
low-fat diet and lowered their body mass index (BMI, a measure of
weight in relation to height used to indicate obesity) by an average
of two units.

By comparison, the group that followed the traditional low-fat diet
generally remained the same and didn't lose or gain any significant
amount of weight.

In addition, researchers found that those adolescents on the
reduced-glycemic-load diet had improvements in insulin resistance --
an indicator of how well the body is handling blood sugar -- that
were above and beyond those attributable to weight loss alone.

Together with obesity, insulin resistance significantly increases
the risk of developing type 2 diabetes. Researchers say the current
epidemic of childhood obesity has spurred a dramatic increase in type
2 diabetes among adolescents, which poses significant long-term health
risks.
 
A New Approach for Obese Children?

"Unfortunately, conventional approaches to dietary treatments for
obesity have had poor long-term effectiveness in any population, let
alone children," says researcher David Ludwig, MD, PhD, director of
the obesity program at Children's Hospital Boston.

Ludwig says obese children and adolescents are one of the toughest
groups to treat because they are at a time in life when many other
emotional, psychological, and developmental changes are already under
way. That makes finding teens that are motivated to lose weight or
adopt dietary habits that are different from their peers especially
problematic.

But adolescents in this study actually preferred the low-glycemic-
index diet to the more traditional diet.

Experts say that by taking the pressure off counting calories and
putting the emphasis on eating until they become full may make it
easier for young people to stick to a diet as well as develop healthy
eating habits.

"Unlike in most long-term weight-loss studies where maximum weight
loss is seen at six months and substantial weight regain occurs at
12 months, in our study we found no weight regain between six and 12
months, providing encouraging signs that this diet might be
sustainable in the long term," says Ludwig.

Ludwig describes the reduced-glycemic-load diet as a middle ground
between the high-fat, low-carbohydrate diets, such as the Atkins
diet, and low-fat diets that tend to be high in carbohydrates.

"It may be a very nice compromise -- more effective than a low-fat
diet but not as extreme and restrictive as an Atkins diet," says
Ludwig.

Ludwig says ultimately the goal of any diet is to reduce calorie
intake to stimulate and sustain weight loss.

"The question is, 'How do you get there?'" Ludwig tells WebMD.
"If you get there with an external calorie restriction as with a
typical diet that leaves the individual or especially the child
feeling excessively hungry or psychologically deprived, then that
individual would be unlikely to follow that diet for the long term,
causing a big risk for weight regain."

Sothern agrees with the emphasis on quality carbohydrates and
lowering sugar intake that are hallmarks of the reduced-glycemic-load
diet, but she says diet is only half of the story in fighting
childhood obesity and reducing the risk of diabetes among
adolescents.

"The diet is only as good as the physical activity it's paired with,"
says Sothern. "You can put people on a low-glycemic diet all you want,
but if they're not physically active, it's only going to have half
the effect it could have if it was combined with exercise."

 

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SOURCES: Archives of Pediatric & Adolescent Medicine, August 2003.
David Ludwig, MD, PhD, director of the obesity program, Children's
Hospital Boston. Melinda Sothern, PhD, director, Prevention of
Childhood Obesity Laboratory, Louisiana State University, Pennington
Biomedical Research Center.