The amount of weight that volunteers lost varied greatly, from zero to 27 pounds, despite the fact that all were essentially eating the same foods in the calorie-controlled meals provided to them at the nutrition center. Keim noted that the finding underscores the need for weight-management plans that are even more individualized than those available today.
The scientists also found that dieters who lost the most weight were those who scored the highest on the Iowa Gambling Task (IGT), a standard test that helps assess, for example, decision making and the ability to resist the temptation of short-term, immediate rewards in favor of longer-term benefits.