Weight management is a growing concern in this country. More than 2 in 3 adult Americans are overweight or obese. At any given time, millions of people are trying to lose weight. Each year, billions of dollars are spent on weight-loss products and services, from diet books to shoe inserts. Learn more about diets and weight loss by taking this quiz, based on information from the Federal Trade Commission (FTC) and Weight-control Information Network (WIN).