A new study by the University of Minnesota in Minneapolis found that teenagers who diet may end up having problems staying slim later in life. To make matters worse, the research shows that teens who use unhealthy ways to lose weight often become trapped in a yo-yo of weight gain and loss. Many young women and men who begin dieting at an early age go to extremes to lose weight, which often becomes a life-long battle with an eating disorder. Read more from Reuters on MSNBC.com.