Glycemic Index: A Magic Weight Loss Solution or a Soap Bubble Ready to Burst?

Experts Take On the Glycemic Index

It sounds like a magic formula for dieters --but experts have long been saying there's no such thing. "If you don't have peaks and valleys in your glucose level then hunger should be kept at bay," says Kathleen Zellman, RD, a spokesperson for the American Dietetic Association (ADA). "However, it's not that simple. It's also affected by meal size, whether there's any fat in the meal, and overall health status."

"Glycemic index looks at individual foods -- not how that food might interact with another," says Connie Diekman, RD, an ADA spokesperson in St. Louis, Missouri. "If you eat a high glycemic index food with a protein, for example, it might be absorbed more slowly. ... That's the hang-up with glycemic index. Very few people will sit down and eat one high glycemic index food and then another. It's meals that we eat."

Michael Jensen, MD, an endocrinologist at the Mayo Clinic in Rochester, Minn., says it's never been proven that high insulin levels -- which result when a high glycemic index food is eaten -- mean increased hunger. "When [you] work with patients who get real hungry between meals, you have to try a couple of different things. I'm not sure if it's glycemic index, the bulk of food, the content of food that gives [the sense of fullness] ... I also have them consider adding protein and modest amounts of fat to decrease overeating between meals."

New research shows that when it comes to type 2 diabetes, not all carbohydrates are created equal. Tufts University researchers report that eating whole-grain foods, especially fiber-rich cereals, appears to improve insulin sensitivity and lower the risk of the metabolic syndrome.

Whole-grain foods have already been found to help protect against heart disease and certain cancers, and the newly published study is one of several that indicates there is a protective role for whole grains against a constellation of major risk factors that lead to metabolic syndrome -- a risk factor for cardiovascular disease and the development of type 2 diabetes.

"Unless you're a diabetic, glycemic index may not be all that important," says Jack Alhadeff, PhD, professor of biochemistry at Lehigh University in Bethlehem, Pa. , who adds that since most of us eat a variety of foods in a meal, the accuracy of the index can be questionable.

But what about the notion that glucose from high-index foods is more likely to be stored as fat?

"The scientific literature is very clear that eating carbohydrates that are embedded in plant cellulose -- complex carbohydrates -- is always better," says Nagi Kumar, PhD, director of clinical nutrition at the Moffitt Cancer Center and professor of human nutrition at the University of South Florida in Tampa. "But the reasons it is better are not because it somehow lessens or alters fat storage."