SOME STARCHY FOODS MAY CONTRIBUTE TO OVEREATING
                                                               
                                                               
                                            Release No. 0078.99

                     Media Contact: Andy Solomon (202) 720-4623
                                          andy.solomon@usda.gov
                   Public Contact: Judy McBride, (301) 504-1628
                                      jmcbride@asrr.arsusda.gov


SOME STARCHY FOODS MAY CONTRIBUTE TO OVEREATING

     WASHINGTON, March 1, 1999-- Meals high in carbohydrates that are rapidly
digested and absorbed appear to trigger a series of hormonal and metabolic
changes that promote overeating in obese people, according to a new study at a
U.S. Department of Agriculture research center.  The study findings are
published in the March issue of Pediatrics.  

     "These findings provide the first solid evidence that carbohydrates are
one piece of the puzzle in determining what makes some people overeat,"
Glickman said.  

     Scientists use the term "high glycemic index"(GI) to describe
carbohydrates that are rapidly digested and absorbed.  The Boston researchers
conclude that high GI meals set off a chain of actions that cause obese people
to overeat. 

     On three separate days, a week or more apart, researchers fed a group of
teenage boys breakfast and lunch with a high, medium or low glycemic index. 
Then they measured changes in the boys' blood glucose, fatty acids and insulin
and other hormones for five hours after breakfast.  Blood glucose and insulin
rose highest and fastest after the high GI breakfast.  Within a few hours,
however, blood glucose and fatty acids dropped significantly, triggering a
stress response, indicated by a rise in the hormone adrenalin.

     After the boys consumed an identical lunch, they were encouraged to
select what they wanted from a platter of foods when they felt "very hungry." 
The subjects ate nearly twice as much after a high GI meal than after a low-GI
meal.  

     About one-fifth of U.S. children and one-third of adults are now
significantly overweight, despite a significant drop in fat intake in recent
years.   Researchers David S. Ludwig at Children's Hospital of Boston and
physiologist Susan B. Roberts at the USDA Human Nutrition Research Center on
Aging at Tufts University believe that the results likely apply to the middle-
aged and elderly as well.  
                                
     According to Roberts, high GI foods include refined grain products and
potatoes, as well as sources of concentrated sugars, such as sodas and fruit juices.  Some
starchy foods have higher GIs than table sugar. Moreover, many of the low-fat
foods that have flooded grocery shelves are also high in calories. Vegetables
and fruits generally have a low GI. 

     Roberts said the findings do not support weight-loss diets based
entirely on the glycemic index because many low-GI foods, including steak,
butter and ice cream, are high in calories.  These low-GI foods trigger
overeating because they are palatable and calorically dense.  

     Ludwig, who directs the obesity program at Children's Hospital, said GI
has a role in weight regulation along with genetics, physical activity,
psychological factors and other dietary variables.  

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NOTE TO EDITOR: Contact for details Susan B. Roberts, PhD, physiologist,
chief, Energy Metabolism Laboratory, USDA Human Nutrition Research Center on
Aging at Tufts, Boston, Mass., phone (617) 556-3238, roberts_em@hnrc.tufts.edu; or David S. Ludwig, M.D., PhD, The Children's
Hospital, Boston, Mass., phone (617) 355-4878, ludwigd@hub.tch.harvard.edu.