Ed Yong in The Atlantic:
Take a slice of cake and cut it in two. Eat one half, and let a friend scoff the other. Your blood-sugar levels will both spike, but to different degrees depending on your genes, the bacteria in your gut, what you recently ate, how recently or intensely you exercised, and more. The spikes, formally known as “postprandial glycemic responses” or PPGR, are hard to forecast since two people might react very differently to exactly the same food.
But Eran Elinav and Eran Segal from the Weizmann Institute of Science have developed a way of embracing that variability. By comprehensively monitoring the blood sugar, diets, and other traits of 800 people, they built an algorithm that can accurately predict how a person's blood-sugar levels will spike after eating any given meal.
They also used these personalized predictions to develop tailored dietary plans for keeping blood sugar in check. These plans sometimes included unconventional items like chocolate and ice-cream, and were so counter-intuitive that they baffled both the participants and dieticians involved in the study. But they seemed to work when assessed in a clinical trial, and they hint at a future when individuals will get personalized dietary recommendations, rather than hewing to universal guidelines.