Not all carbs affect everyone the same way, and your personal blood sugar response might hold clues about your metabolic health. New research from Stanford Medicine suggests that how your body reacts to specific carbohydrates could reveal whether you're insulin resistant, have beta cell dysfunction or fall into a healthier category altogether.
In the study, which was published in Nature Medicine, 55 adults wore continuous glucose monitors and ate the same seven carbohydrate-rich foods — including rice, potatoes, black beans, pasta and grapes — on different days. The researchers then compared each participant’s blood sugar response against detailed metabolic profiles.
The biggest takeaway: glucose spikes to the same food varied depending on a person’s underlying physiology. For example, people with insulin resistance saw the biggest spikes after eating pasta, while those with beta cell dysfunction spiked more dramatically after potatoes.
“This study suggests that not only are there subtypes within prediabetes, but also that your subtype could determine the foods you should and should not eat,” said Michael Snyder, PhD, professor of genetics at Stanford.
Interestingly, everyone spiked after eating grapes, but the ratio of one’s blood sugar response to grapes vs. potatoes may one day serve as a real-world biomarker for insulin resistance.
Researchers also tested whether eating fiber, protein or fat before carbs reduced glucose spikes. It worked for people with healthy metabolism but had little effect for those with insulin resistance.
“Eat your salad or hamburger before your French fries,” Snyder advised, emphasizing that timing and food order might still help reduce blood sugar spikes.
The findings open new possibilities for using personalized nutrition to prevent or delay diabetes in high-risk individuals.
This study was funded by the National Institutes of Health, the National Library of Medicine, the Stanford Precision Health and Integrated Diagnostics Center, the Stanford Diabetes Center, the American Diabetes Association and the Nutrition for Precision Health initiative.