The Hungry Brain: Outsmarting the Instincts That Make Us Overeat

by Stephan Guyenet

Ravussin and his team wanted an intermediate method, one that had the accuracy of the metabolic ward but allowed people to select their own diets, replicating everyday life as much as possible. Their solution was to install enormous U-Select-It 3007 vending machines inside a metabolic ward, each containing a variety of entrées, snacks, and beverages. The foods in the vending machines were not chosen at random—“We were screening what people liked and disliked,” explains Ravussin—and only included foods that were tempting. The menu included things like french toast and sausages with syrup, chicken pot pie, chocolate-vanilla swirl Jell-O pudding, cheesecake, nacho cheese Doritos, M&M’s, Shasta cola, and a few apples for the health nuts (no Froot Loops, sadly)—in other words, mostly “palatable human foods” similar to those Sclafani used in his rat study. Ten male volunteers were locked up with the vending machines for seven days with the freedom to select when and what they ate. To monitor their food intake, each person had to enter an ID code when he withdrew food and return all uneaten food to the research staff for weighing. The experiment was a success: Ravussin’s team was able to accurately measure food intake in people who were selecting their own food, and at the same time take a number of other informative metabolic measurements. Yet during the course of the study, something remarkable dawned on Ravussin: The volunteers were overeating tremendously. “People were on ave...