e all know at least one person on a low-carbohydrate diet who has lost weight and authoritatively informed us that carrots, corn, and potatoes will make you fat because they are very high in sugar. While I value the importance of learning from others, I feel that it's important to help set the record straight about "high carbohydrate" foods.

Several popular diets, like the South Beach diet, The Zone diet, Sugar Busters, and the Atkins diet, have focused the public's attention on a scientific tool called the Glycemic Index. The Glycemic Index (GI) measures how much a food containing 50 grams of available carbohydrate raises a person's fasting blood sugar over the course of two hours. Relative to glucose, which has a GI ranking of 100, a GI ranking under 55 is considered low, 56-69 is considered moderate, and above 70 is considered high. According to this scale, watermelon, corn, carrots, bananas, and pasta are all high-GI foods, meaning they can raise blood sugar substantially. The creators of these popular diet plans base their dietary recommendations on these numbers to tell followers which foods to eat and which to avoid. Unfortunately, people have come away with the idea that foods containing carbohydrates are to be avoided and replaced with as much protein as possible. Assigning a GI value as a means of comparing foods can be very misleading. For example, French fries have a GI ranking of 75 and a baked potato has a GI ranking of 85. Both rankings are considered high, but the French fries, which rank better than the baked potato, contain 540 calories, 26 grams of fat, and five grams of saturated fat (and undoubtedly some trans fats). The baked potato has just 185 calories, no fat, and plenty of B vitamins and minerals. One item can help promote health, while the other can contribute to overweight and heart disease-but you wouldn't know it by using the GI as a guide.

Many factors impact the Glycemic index score, including how processed a food is (old-fashioned oatmeal causes less of a rise in blood sugar than instant oatmeal), how much fiber a food contains (fiber slows the release of glucose into the blood), the amount of fat and protein in the food (especially relevant to mixed dishes and meals, since fat and protein have little Glycemic effect and they slow the rate of digestion and absorption), and how much the starch has been cooked (water and heat can cause starch molecules to swell and burst, changing the texture of the food, making it more easily digestible, and therefore increasing the amount of sugar released into the blood).

The Glycemic index is not practical because it ignores other health benefits a food may offer, it doesn't take into account the effect of eating a food as part of a meal that contains other components, like protein and fat, and most notably, it does not take serving size into account. For instance, carrots have a GI of 93 (high), but that number is based on eight or 10 fasting subjects who had to eat one and a half pounds of carrots, since it takes that much to total 50 grams of digestible carbohydrates (total carbohydrates minus fiber, in grams). A more practical way to use the information in the Glycemic Index is to convert it to Glycemic Load.

Glycemic Load (GL) takes a standard serving size into account, rather than just a fixed amount of carbohydrate. It is calculated by dividing the Glycemic index score discussed earlier by 100, and multiplying the result by the amount of available carbohydrate in a standard serving. Therefore, carrots' GL= 93/100 x four grams carbohydrate = four. A GL of 10 or less is low, 11-19 is moderate, and 20 or more is high. That's good news for watermelon, too, since it turns out that although the GI is high at 72, the GL for a four-ounce serving is four-very low. Watermelon offers fiber, vitamin C, and lycopene, which helps protect against prostate cancer. It's also low in calories, refreshing, and satisfies a sweet tooth as well as ice cream (which deceptively has a lower GI and GL due to the high fat content!).

I feel that it's important to take a step back and evaluate what these diets are really recommending. Any diet that tells you to eliminate fruits and vegetables should set off alarm bells in your head-especially if they're promoting salty cheese snacks and artificially sweetened ice cream in their place. We don't need to assign a number to a food to know if it is healthy. If you look critically at a Glycemic Load scale (they're actually pretty hard to fin, but check out www.glycemicindex.com if you're curious), you'll notice that vegetables, fruits, milk, and whole grain products are low on the scale, and more refined foods are high on the scale. So basically, cutting out highly processed foods and replacing them with whole or minimally processed foods is a great way to control blood sugar and lose weight. Take regular pasta and whole wheat pasta, for example. You know that whole wheat pasta is healthier because it contains much more fiber and nutrients than the more processed pasta, so it helps fill you up faster and keep you full for longer, saving you many calories in the short and long run. If you need more proof: regular spaghetti has a GI of 64 and a GL of 27, while whole-wheat spaghetti has a GI of 32 and a GL of 14. Whole grains and fresh produce offer many health benefits, including protection against diabetes, heart attacks and strokes, promotion of proper bowel function, and reduction of the risk of several cancers.

If you want to lose weight and/or control your blood sugar, here's my recommendation: choose whole, minimally processed grains over refined grains and pair them with some protein. This healthy combination helps keep blood sugar steady, suppresses appetite, and controls cravings. That should be helpful in your weight loss efforts. For good whole grain + protein combinations, see my article Super Snacks for Healthy Kids in this newsletter. In the meantime, try the following healthy carbohydrate substitutions:

• Breakfast: If you're eating anything but a whole grain cereal with nonfat milk or soy milk, you're missing out on a potential eight-pound weight loss. Try Kashi Go Lean or Go Lean Crunch, Nature's Path Optimum Slim, or McCann's steel cut Irish oatmeal.

• Breads: Forget white and fluffy and go for dense and hearty. Try Milton's healthy whole grain, Food for Life breads, Vogel mixed whole grain and whole-wheat sesame, Millbrook 100% whole-wheat, Rudi's Organic honey sweet whole-wheat, Roman Meal 100% whole-wheat, and Stone Ground nine-grain bread.

• Pasta: Don't think that it should ever be the main course, even if you can eat 3 cups of noodles at a restaurant. Pasta is a side dish (so are potatoes, rice, and the like) but whole wheat pasta is more filling, so it's easier to control your portions. Try De Cecco whole-wheat penne and Pritikin whole-wheat spaghetti and rotini.

• Rice and potatoes: Like regular pasta, it's easy to eat a lot of these starches. Try alternative starches like brown rice, basmati rice, wild rice, pearled barley, Grain Gourmet cracked wheat bulgur, Near East taboule, Seeds of Change quinoa, Wolf's kasha, and waxy new potatoes in pink, yellow, or purple.