Scientists compare glycemic ratings to calorie intake
By DAVE WILKINS
University of California-Davis nutrition scientists are conducting a 15-week study to see whether diets that contain potatoes will be useful in helping people lose weight or maintain a healthy body weight.
Specifically, the study will look at which is more important -- eating foods that are low in calories or eating foods that have a low glycemic index rating.
The glycemic index is a ranking of carbohydrates according to the extent to which they raise blood sugar levels after eating.
"So far we are finding out that calories are more important than the glycemic index for weight loss," said Britt Burton-Freeman, the principal investigator of the study funded by the U.S. Potato Board.
Potatoes are one of the higher-ranked foods on the glycemic index scale. A baked Russet Burbank without anything on it registers 111 on the scale, compared with a 30-gram serving of enriched white bread at 41.
Potatoes have received a lot of negative press in the public debate about nutrition and weight loss in recent years, Burton-Freeman said. Some experts advocate low-glycemic foods for weight loss because they help control appetite and delay hunger.
The Davis study is expected to contribute to a better understanding of just how potatoes really stack up.
"It will be a good study," Burton-Freeman said. "It's a hot area."
In the study, 90 healthy adults between 25 and 35 will go on a diet that includes potatoes. They'll meet weekly with a dietitian and get guidance on how to incorporate potatoes into their diet.
While potatoes rank high on the glycemic index, industry groups point out the positive aspects of the potato, including its no-fat, high vitamin and mineral content.
The U.S. Potato Board launched its Healthy Potato Campaign in 2004 to counter some of the negative perceptions.
One medium-sized potato has only 110 calories, zero fat and is packed with vitamins and minerals, the organization points out.
Potatoes contain 45 percent of the recommended daily value of Vitamin C -- about the same as a tangerine.
Potatoes rank highest for potassium content among the top 20 most frequently consumer raw vegetables and the top 20 most frequently consumed raw fruits.
Staff writer Dave Wilkins is based in Twin Falls, Idaho. E-mail: email@example.com.