Star ratings reflect scores of 1 to 5 assigned to the glycemic-index diet in eight categories by nutritionists, specialists in diabetes and heart disease, and other diet experts on a ratings panel assembled by U.S. News. (See our Best Diets methodology.) While they found GI diets mostly safe and nutritionally adequate, the experts largely handed out lackluster 2s and 3s otherwise. As a heart-health or weight-loss diet, it doesn’t look promising. And it’s pretty difficult to follow. Below, ratings in all categories and how the experts’ opinions broke down.
Short-Term Weight Loss
The GI diet didn’t stir up much enthusiasm for an ability to produce meaningful weight loss quickly; the panelists placed it near the bottom of the pack. The experts gave it less than 3 stars and noted the dearth of research that might support the diet’s short-term weight-loss potential.
Long-Term Weight Loss
The panel thought even less of the GI diet’s long-term potential for weight loss. Without good research to convince them otherwise, experts didn’t think dieters would sustain significant weight loss in the long run. The panel’s combined rating was just 2.2 stars, which is considered minimally effective.
Easy to Follow
No, said the panel. It’s anything but. Unhealthy foods can be low-GI and healthy foods can be high-GI, and there’s no comforting reservoir of supportive information. The experts rated the diet slightly below its long-term weight loss score.
Moderately complete, the experts concluded. They compared it with the federal government’s 2010 Dietary Guidelines and gave it a mix of 2s, 3s and 4s that produced a rating of about 3—O.K., but still trailing many of its peers.
The GI diet doesn’t pose serious safety concerns, according to our experts. This category earned the diet a rating of 3.8—its highest score and in the middle of the group.
Although the glycemic index was originally developed to help diabetics manage their condition, it did only middling well in that regard with our panelists. It got a rating of under 3 stars, trailing more than half of the other diets.
For Heart Health
The GI diet did even worse with the experts in heart health than it did in diabetes. The panel gave it 2.3 stars, not much above minimally effective, in preventing cardiovascular disease and improving heart-health markers. Without much evidence to back its worth, the GI diet trailed many of its competitors in this category.
Last updated by Kurtis Hiatt | December 12, 2013