By Jennie Brand-Miller, PhD; Thomas Wolever, MD, PhD; Kaye Foster-Powell; Stephen Colagiuri, MD
Originally conceived to aid diabetics, the glycemic index is a way of measuring the effect a carbohydrate food has on blood sugar. Now several researchers of the index say it can help healthy people lose weight. By consuming foods that are more slowly digested (lower on the index), they claim, you feel less hungry and eat fewer calories.
What the experts like: Most gave this diet a big thumbs-up. Lash and Economos agree that the foods recommended are generally healthy and that the book offers clear guidelines. "It's particularly good at describing the difference between healthy and unhealthy carbohydrates," says Perry-Bottinger.
What they don't like: The main criticism is that the glycemic index is a good concept, but it's been taken too far. Instead of obsessing over what glycemic rating a piece of bread has, says Nelson, "it's the whole pattern of the diet that makes the difference—the variety of nuts, seeds, lean meats, legumes, fruits, vegetables, grains. If you forget about the index and focus on those foods, you'll see improvement in almost every area, from cholesterol to weight loss."
Crunching the numbers: At about 1,800 calories a day, the diet is fairly balanced—moderate in carbohydrates and protein, low in fat, with plenty of fiber. Its only notable deficiencies are vitamins D and E.