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- High-GI carbs like white bread are not more likely to cause weight gain than their low-GI counterparts, a study found.
- Researchers analyzed data on 2 million adults with high-glycemic and low-glycemic diets.
- Other qualities like nutrient density and dietary fiber are more important, according to the study.
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High-glycemic foods are no more likely than low-glycemic ones to lead to weight gain, according to a study published this week in "Advances in Nutrition," a peer-reviewed journal from the American Society for Nutrition.
The glycemic index (GI) was introduced in 1981 by David Jenkins, a professor at the University of Toronto. Jenkins assigned a number from 0 to 100 to a food as a measurement of how quickly the body breaks down carbohydrates.
Consumers have since been told that too much high-glycemic foods – like processed foods, candy, and sodas – can make them fat, leading them to swap the white bread for brown and Frosted Flakes for oatmeal. These foods have been dubbed "fast carbs" or "simple carbs" for how quickly they raise blood sugar levels, which can promote fat storage and increase the risk of diabetes and obesity.
After analyzing data on nearly 2 million adults from 43 cohort studies, scientists concluded that there were no consistent differences in body-mass index, or BMI, between adults who consumed more fast carbs and those who had lower GI diets.
70% of the 27 cohort studies that compared the differences between low-GI and high-GI diets for weight loss either showed that they had similar BMIs, or that BMI was actually lower in the groups with the highest GI, according to the study.
"Contrary to popular belief, those who consume a diet of high-GI foods are no more likely to be obese or gain weight than those who consume a diet of low-GI foods. Furthermore, they are no less likely to lose weight," Glenn Gaesser, one of the study's co-authors and professor of exercise science at Arizona State University, said.
Other qualities of carbs, like nutrient density, dietary fiber, and amount of added sugar, are more important than its glycemic index, the researchers contended.
"The key takeaway is that carbohydrates, regardless of type, can be part of a healthy diet and have a place on a healthy plate," co-author Julie Miller Jones, a professor at St. Catherine University, said.