WASHINGTON — A recent study published in the Advances in Nutrition, a peer-reviewed journal from the American Society of Nutrition, concluded that high-glycemic foods, or “fast carbs,” and low-GI foods, or “slow carbs,” do not lead to weight gain or to diet-induced weight loss.
Scientists hypothesized that high-GI foods promote fat storage and increase risk of obesity by causing a rapid increase in blood sugar and insulin secretion, and that low-GI foods do the opposite. The study analyzed data on 43 cohorts from 34 publications (comprising nearly two million adults) to assess if dietary glycemic index impacts body weight.
“This study is the first to definitively demonstrate that fast carbs do not make you fat,” said Glenn Gaesser, PhD, study co-author and professor of exercise science in the College of Health Solutions at Arizona State University. “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.”
This is groundbreaking as it is the first study of its kind to show that fast and slow carbs do not affect body weight.
“You can forget about glycemic index as a meaningful contributor to your body weight or efforts to lose weight,” Dr. Gaesser said. “It’s just not that important. There are other factors that are far more important in terms of determining what you’re going to weigh and how much you’re going to lose.”
The study’s co-authors Julie Miller Jones, PhD, LN, CNS, and Siddhartha Angadi, PhD, highlighted the key takeaways for consumers in the context of ever-evolving nutrition research.
“The review questions the premise that low-GI diets lead to substantially better weight control outcomes and reminds us of the many qualities of carbohydrates that are far more important to consider, for example, nutrient density, dietary fiber and whole grain content, and percentage of added sugar,” Dr. Angadi said.
The study also highlighted the need for both researchers and nutrition communicators to be mindful of the many positive nutrients that staple carbohydrate foods contribute to diet quality, as well as the detractor nutrients that indulgent foods often contain. This nuance is important when characterizing or communicating the quality of carbohydrates.
“The key takeaway is that carbohydrates, regardless of type, can be part of a healthy diet and have a place on a healthy plate,” Dr. Miller Jones said. “Over the past few decades, we’ve seen the blanket vilification of carbs, processed foods, and foods made with refined grains. Science has shown that these foods in the right balance can be part of a dietary pattern that can promote a healthy weight and reduce disease risk.”
For the wholesale baking industry, this is an enormous break-through.
“This study takes away the message that carbs make you fat which has been the most consistent tool that anti-carb folks have used,” said Erin Ball, director of public relations and science at Grain Foods Foundation. “The industry can now march forward saying, ‘Hey, guess what? These don’t make you fat and let us remind you of all the things that are great about these products.’”
The new published study can be found here.