The thinnest people eat the most carbs, a four-nation survey shows. If you’ve been following the latest U.S. diet fads, that isn’t what you’d expect. But the data come from an intensive, four-nation study of more than 4,000 men and women age 40 to 59. The study was based on food diaries kept by people in the U.S., U.K., Japan, and China. Study leader Linda Van Horn, PhD, of Northwestern University, presented the findings at the 44th American Heart Association Annual Conference on Cardiovascular Disease Epidemiology and Prevention, held this week in San Francisco.