THE DETAILS: Researchers used data from food questionnaires administered to a large population of Italians between 1993 and 1998. The study sample included 47,749 adults, most of whom (32,578) were women. Eight years after the food survey data was collected, the researchers followed up with the patients and found that 463 had developed coronary heart disease. They also found that women, but not men, with the highest intake of carbohydrates were twice as likely to develop heart disease. The risk was 68 percent higher when those carbohydrates came from foods with a high GI, and women who had a high glycemic load—that's the combined glycemic index of all the foods consumed—had a still greater risk. Women who ate a lot of low-GI carbs didn't see the same increase in risk.
WHAT IT MEANS: Certain types of carbohydrates can raise your risk of heart disease, and it all depends on their glycemic index. Simple carbohydrates, such as white bread, white rice, and certain breakfast cereals, are considered high-GI carbs, meaning that, on a scale of 0 to 100, they register in the 70-plus range. Low-GI foods are below 55 on that scale, and include healthy complex carbs like oats, cereals like All-Bran, and most fruits. So the key is not to give up carbs completely. It's learning how to avoid the ones that cause your blood sugar to spike. You'll save your heart and feel better, too, since blood sugar spikes are responsible for the tired feeling you get a few hours after eating, when levels plummet.
Here are a few tips for navigating the index:
• Stick with whole foods. Because the glycemic index isn't advertised on a food's label or on the Nutrition Facts panel, it can be hard to find out what the glycemic index of your favorite brand of bread is. In general, the healthiest foods tend to have the lowest glycemic index. That includes stone-ground whole wheat bread, rolled oats, oat bran, pasta, barley, bulgur, beans, lentils, legumes, most fruits, and non-starchy vegetables. Medium-GI foods include whole wheat bread, quick-cooking oats, and brown rice. High-GI foods include most "white" foods (like white bread and white rice, sugary cereals and instant oatmeal, and snacks like pretzels and popcorn). But they also include melons, pineapple, and white potatoes. Counting carbs can help to a certain extent, as the number of carbs is usually (but not always) a good predictor of glycemic index. See a list of familiar high and low glycemic-index foods on Prevention.com.
• Combinations matter. You don't have to eat just low glycemic-index foods, the Diabetes Association says. Just make sure that a high-GI food is balanced with two or three other low- or medium-GI foods. Reserve a quarter of your plate for high-GI foods, and fill the rest up with healthier alternatives.
• Boost your fiber intake. Foods high in fiber tend to have a lower glycemic index, and they'll make you feel fuller. For breakfast, replace high-GI cornflakes and white toast with low-fat yogurt mixed with fresh fruits or dried apricots and muesli (a kind of low-fat granola), and for lunch, have a sweet potato and fresh vegetables or lentil soup rather than a sandwich from the deli. For more low-GI and high-fiber recipes, check out the Rodale Recipe Finder.