Investigators randomized 224 overweight or obese adolescents to either dietaryintervention including parental counseling, grocery coupons, and home delivery of noncaloric beverages or a control group with no intervention.
The lower intensity of dietaryintervention for the control group during the first few years might have caused a bias toward a benefit in the two Mediterranean-diet groups, since the participants in these two groups received a more intensive intervention during that time.