1. The study will be consist of two main periods: an intervention period of 3 months followed by 21 months of a follow up period. During the intervention period, participants (parents or both parents and children, depending on randomization) will attend a behavior intervention program once a week, each session will last one hour and would be guided by dietician and psychologist. Follow up visits will be performed at the clinic (for participants in all 3 groups) at months 0, 3, 12 and 24.