Individual responses to carbohydrate intake vary widely due to metabolic health factors, with insulin-resistant individuals experiencing greater blood sugar spikes from foods such as rice and potatoes. Digest
Not everyone handles carbohydrate intake the same way. In fact, the spike in blood sugar that follows a meal—called the postprandial glycemic response—can vary widely between individuals, even when they eat the same food. A recent study found that individual responses to carbohydrate-rich meals, such as rice or potatoes, depended strongly on a person's underlying metabolic health, with people who were more insulin resistant showing much greater blood sugar spikes.
Researchers measured blood glucose levels continuously in 55 participants (using continuous glucose monitors) as they ate seven standardized carbohydrate meals, including bread, rice, potatoes, and grapes. They also tested whether "preloading" a carbohydrate-rich meal with fat, protein, or fiber could blunt blood sugar spikes. Participants underwent intensive metabolic testing and provided blood and stool samples so the researchers could analyze insulin resistance, beta cell function, blood lipids, proteins, and gut microbes.
The study revealed striking differences between individuals in their responses to different carbohydrate meals. Rice triggered the highest average blood sugar spike, but the size of that spike varied by person. For example, people who responded most strongly to potatoes were 25% more likely to be insulin resistant and have weaker beta cell function, while those who spiked after grapes were more insulin sensitive. Those who spiked in response to rice were more likely to be Asian; those who spiked in response to bread tended to have higher blood pressure. Preloading with fat, fiber, or protein worked better for people with good insulin sensitivity.
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Molecular analyses revealed that insulin-resistant participants had higher levels of triglycerides linked to poor metabolic health, while those with elevated blood pressure showed distinct patterns in circulating metabolites. The gut microbiome also differed between high and low responders, with microbial pathways involved in carbohydrate metabolism more active in those with larger blood sugar spikes.
These findings suggest that a one-size-fits-all approach to managing blood sugar may fall short. Understanding a person's unique metabolic profile—as well as their microbiome—may be essential for preventing or managing conditions like type 2 diabetes and cardiovascular disease. Learn more about the gut microbiome's role in regulating blood glucose and cholesterol in this clip featuring Dr. Michael Snyder, the lead investigator on this study.