Hooked: How Processed Food Became Addictive

by Michael Moss

The speed with which glucose enters the blood has prompted some nutritionists to embrace a concept called the glycemic index, which seeks to measure how fast certain foods raise the level of sugar in the blood. Some of its rankings are counterintuitive. Adding some sugar to starchy food, for instance, actually lowers the starchy food’s speed in reaching the blood by holding the starch molecules together in a way that causes them to resist digestion. Indeed, some scientists dismiss the whole index as being too simplistic to capture all the complexity of food. But by the glycemic theory, products that are highly refined will send our blood sugar soaring the fastest, and the faster it soars, the faster it hits the reward system in the brain. Bread using refined flour is high on the GI list;24 corn tortillas are not. Cornflakes are high; All-Bran is not. White potatoes are high; carrots are not. By this reckoning, carrots and corn tortillas and All-Bran would be seen as less rewarding by the brain and pose less of a risk that they’d put in motion the behavior that can lead to addiction: seeking reward without weighing the risk. Elevating the go brain over the stop.