A Sept. 7 Health article incorrectly said that adding foods with a higher glycemic index can help mute the rise in blood sugar that occurs after consumption of other foods with a high glycemic index. Adding foods with a lower index -- for example, adding salmon and cream cheese to a bagel -- helps reduce the increase. (Published 9/15/2004)
Corn flakes, ice cream, instant oatmeal, mashed potatoes, french fries and couscous.
A recipe for a bad clean-out-the-fridge dinner? No, a list of foods that raise blood sugar levels higher than pure table sugar does. Or, to put it differently, foods with a high glycemic index.
With an estimated 17 million Americans already diagnosed with diabetes and millions more likely to develop it, eating according to the glycemic index -- that is, taking into account how much a food raises blood sugar and overtaxes insulin production -- is gaining interest from scientists, physicians and the public.
Some think that the glycemic index could even help settle the acrimonious debate between low-carbohydrate and low-fat eating plans.
"It's the perfect compromise between the two," said David Ludwig, director of the Optimal Weight for Life program at Children's Hospital in Boston. "It's recognized as healthy, it's much more flexible. It doesn't involve severe restriction of either fat or carbohydrates and will be vastly easier to follow, much more satisfying and less psychologically challenging. . . . It's very consistent with the Mediterranean diet.'"
Eating according to the glycemic index hasn't been overlooked by diet book authors. The best-selling "Sugar Busters" (Ballantine) series, by a group of New Orleans doctors, is based on the glycemic index approach. So is the "Eat Yourself Slim" (Erica House) series by Michel Montignac and the more recent "Glycemic Index Diet" (Workman) by Rick Gallop. The concept is also a key part of the popular "South Beach Diet" (Rodale).
Low glycemic foods include plenty of fruit, vegetables, beans, nuts, whole grains and healthy fat, such as olive and canola oil, plus lean meat, poultry without the skin and seafood. High glycemic foods are generally highly processed foods, with minimal amounts of fiber and lots of sugar. But there are exceptions -- including white potatoes, which have a significantly higher glycemic index than sweet potatoes.
In recent years, studies have pointed to benefits of low glycemic foods not only for controlling blood sugar and body weight, but also for reducing levels of unhealthy blood triglycerides and boosting beneficial fat, high-density lipoprotein (HDL).
Eating a diet rich in low glycemic foods also seems to cut levels of C-reactive protein, an indication of inflammation associated with increased heart disease risk.
Most recently, "studies show that low-glycemic-index foods seem to potentially have a protective effect for some types of cancer, especially for colon cancer," said David Jenkins, chairman of nutrition and metabolism at the University of Toronto.
Exactly how high glycemic foods may impact health risk is still under investigation. But an animal study published by Ludwig in last week's issue of the British journal The Lancet provides some clues. In the study, one group of rats ate a starchy diet of high-glycemic foods while another received a starchy diet of low-glycemic food.
The study found that the rats eating high-glycemic food had 71 percent more body fat and 8 percent less lean body mass than those on the low-glycemic diet -- despite weighing the same.
The animals that ate high glycemic food also had significantly higher blood glucose and insulin levels, three times the blood levels of trigylcerides and more cell abnormalities in the pancreas, the organ that produces insulin.
The findings suggest, Ludwig said, that "glycemic index is an independent factor that can have dramatic effects on the major chronic diseases plaguing developed nations -- obesity, diabetes and heart disease." Whilethese findings come from a study on rats, the evidence warrants further investigation in humans, Ludwig said.
Until scientists sort out all the glycemic index issues, here's what experts recommend:
No need to play the numbers. Sure, you can find plenty of glycemic index food lists to buy, read religiously -- and drive yourself crazy.
"I recommend against eating by the number for any diet," said Ludwig, who advises action that will sound very familiar to Lean Plate Club members: "All you need for most situations is to eat an abundant amount of fruit and vegetables and legumes [beans] and cut back on foods with refined starch and concentrated sugar," he said. "Fats can be eaten liberally as long as they are healthful fats. You need adequate amounts of protein, which could quite easily be from vegetarian sources" such as soy and other beans.
Eat little and often. Consume five to six small meals about two to three hours apart to keep blood sugar levels -- and insulin production -- steady. But the operative word here is small: about 200 to 300 calories per meal. If those little meals grow large, odds are you will, too.
Skip the whole-wheat pasta. Unless you really love it. White pasta is a dehydrated food that ranks low on the glycemic index, in fact "markedly lower than white bread," said Ludwig. Whole-wheat pasta simply has added wheat bran, which adds some fiber but "which does not lower the glycemic index at all," Ludwig notes. So have the regular pasta -- just be sure to limit portions to a cup of cooked pasta or less.
One more tip: Eat pasta al dente, cooked until firm but chewy. "It not only tastes better," Ludwig notes, "But it also has a lower GI index."
Add some healthy fat. Ludwig, Jenkins and Walter Willett of the Harvard School of Public Health are among the growing number of scientists who say that evidence suggests healthy fat -- olive, canola, safflower, sunflower and flaxseed oils, for example -- can help both with satiety and keeping blood sugar levels even.
Go ahead, snack. Just be smart about it. Choose popcorn instead of potato chips. Dip slices of red pepper, baby carrots and celery into bean dip, guacamole (a source of healthy fat) or salsa. Sip vegetable juice instead of fruit juice. Better yet, eat the fruit itself with a few nuts. And if you're tempted to have a sweet treat, make it a small one with a mix of sugar, healthy fat and protein, such as M&M's with peanuts.
Mix it up. That's an easy way to reduce the blood sugar effects of your favorite high-glycemic foods. So if you can't live without a sesame bagel, Rice Krispies and white rice, simply add foods that have a higher glycemic index to mute the rise in blood sugar. Eat those Krispies with skim milk, berries and a few nuts. Spread whipped regular cream cheese -- not nonfat, which is a high glycemic food -- on just half a bagel and add a slice of smoked salmon. Eat white rice with plenty of vegetables, a little lean meat, poultry, fish or beans.
Boost physical activity. In China, where white rice is a staple, rates of obesity and diabetes have been relatively low until recently. Not only is a more Western diet creeping into the country, but physical activity is declining. The glycemic index "probably doesn't matter at all, provided that you keep your body mass index under 23," Jenkins said. "If you stay skinny and physically active, you don't have to worry about all this nonsense."
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