Hall has done two small but rigorous studies that contradict common wisdom that faults carbohydrates or fats by themselves. In both experiments, he kept participants in a hospital for several weeks, scrupulously controlling what they ate. His idea was to avoid the biases of typical diet studies that rely on people’s self-reports, which rarely match what they truly eat. The investigator, who has a physics doctorate, has that discipline’s penchant for precise measurements. His first study found that, contrary to many predictions, a diet that reduced carb consumption actually seemed to slow the rate of body fat loss. The second study, published this year, identified a new reason for weight gain. It found that people ate hundreds more calories of ultraprocessed than unprocessed foods when they were encouraged to eat as much or as little of each type as they desired. Participants chowing down on the ultraprocessed foods gained two pounds in just two weeks.
