People’s bodies respond differently to the same meal, even when it’s a healthy choice, according to a study from the Weizmann Institute of Science in Israel. Approximately 800 adults gave detailed information on their diets, lifestyles, and medical histories. During one week, they used smartphone apps to record all their daily activities, including the food they ate, while glucose monitors kept track of their post-meal blood sugar levels. Stool samples also were taken for analysis of gut microbiomes. The participants ate their normal diets, except for identical breakfasts, which allowed the researchers to compare people’s responses to the same meal following a fast. Results showed significant variation in blood sugar responses to particular foods, depending on the person. For example, in one woman, tomatoes were associated with a surge in blood sugar.
Age and body weights also influenced how bodies responded to foods. Although diets were personalized and greatly differed from one person to the next, several of the gut microbiota were consistent across participants. In a final step, the researchers created individual diets for 26 people, by feeding all their data into an algorithm that predicted what foods would cause large spikes in blood sugar and which foods would not. For some people, a “good” diet included pizza and potatoes, for others these foods were entirely eliminated. Participants spent a week on their personal “good” diet and one week on a “bad” diet. On average, the good diets lowered post-meal blood sugar spikes and altered the make-up of gut bacteria. The researchers conclude that assuming we know how to treat obesity, while the fault lies in people not listening might be wrong. “…Maybe people are actually compliant but in many cases we were giving them the wrong advice.”
Zeevi D, Korem T, Zmora N, et al: Personalized nutrition by prediction of glycemic responses. Cell 2015; 163 (5):1079.