Randomized, controlled, open, comparative intervention study in 270 children at risk for obesity.Patients will be randomly allocated into one of two behavior intervention groups or control group in ratio of 1:1:1.The study will 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 al 3 groups) at months 0, 3, 12 and 24.

Randomized, controlled, open, comparative intervention study in 270 children at risk for obesity.

Objectives:

1. To develop an intervention program for obesity prevention in children aged 5-10 years old, who are at risk to develop obesity
2. To compare between the efficacy of two different intervention programs and a control group in preventing obesity in the short and the long term.
3. To evaluate the role and significance of including parents in an intervention program for obesity prevention.
4. To identify demographic parameters, lifestyle characteristic and biochemical markers that predict the risk of developing obesity and the response for treatment.

Randomization:

Patients will be randomly allocated into one of two intervention groups or control group in ratio of 1:1:1. Each group will contain 12-15 participants.

Intervention groups:

1. parent's group- only parents will take part at the intervention program.
2. Parents and children group- both children and parents will take part at the intervention program, in two separate sessions.

Methods:

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.
2. Height, weight, fat mass and waist circumference will be measured at 0, 3, 12 and 24 month. Height and weight of parents will also be measured at these visits.
3. Physical examination will be performed at 0, 3, 12 and 24 month.
4. Psychological and nutritional questionnaire (depression, quality of life and self estimation) will be filled at 0, 3, 12 and 24 month.
5. Fasting blood tests for: chemistry, hematology, lipids, glucose, insulin, TSH, adiponectin, IL-6 and TNFα will be performed at 0, 3, 12 and 24 month.

Inclusion Criteria:

• Children aged 5-10 years old
• BMI in 85-98 percentile
• Both parents signing informed consent form

Exclusion Criteria:

• Chronic disease or chronic use of medication
• Incapability to perform all study procedure