Objectives: Aim of this study is to evaluate the effectiveness of Facebook-delivered lifestyle counseling intervention on overweight and obese adolescent's physical activity, BMI and adherence to healthy lifestyles.

Design: A 12-week, randomized controlled trial with three, 24 and 36 month follow-up.

Settings: One of the Northern Finland healthcare districts school health care units.

Participants: all overweight or obese 13-16 years old adolescent and their parents were invited to study.

Methods: Adolescents were stratified by gender, age, and self-reported physical activity and they were randomized into three groups. Two experimental groups, where those both got Facebook-delivered lifestyle counseling and one of the experimental groups got activity monitor which showed the daily activity. One group served as a control group. Parents were allocated to intervention groups according which group their adolescent were randomized.

Outcomes: physical activity,body mass index (BMI) adherence to healthy lifestyles. Baseline measurements have been done and assessment to adherence to healthy lifestyles have been measured. Follow-up measures have been conducted three months after baseline. Adherence to healthy lifestyles measurement follow-up is at 24 and 36 months after intervention.

Adolescents inclusion criteria: weight-fof-height over 20% over normality (finnish recommendations), age 13-16 years old Exclusion criteria: mental health problems, or long term illness.

Adolescents outcome measures:

1. Change from baseline physical activity at 12 weeks using a blinded Polar Activity activity monitor. Primary outcome is measuder using continuous scale and measurement unit is one minute. For each subject the minutes per day is calculated (minimum value is 0).

   It is a wrist worn uni-axial accelerometer designed to determine physical activity of children and adolescents. Polar activity monitor records activity in every 30 seconds bouts and the device records steps when user takes >70 steps per minute. Activity measurements were done for 21 days at baseline and three months follow-up measurements. A wear-time shows valid days in this study, and one valid day required at least 500 minutes / day and users had to have at least eight valid days from weekdays and also one from weekend.

   The device integrates the total amount of acceleration in one dimension and counts physical activity quantity and quality, amount of steps and total energy expenditure in calories (Kcal). Physical activity is defined by metabolic equivalent of tasks (MET), which are divided in five areas of activity; very light (1-2 MET), light (2-3.5 MET), moderate (3.6-5 MET), vigorous (5.1-8 MET) and vigorous plus (>8 MET).

2. Change from baseline body mass index (BMI) at 12 weeks BMI was calculated from weight (kg) and height (cm) that were measured by heath care professionals. Formula BMI= weight (kg)/(height (m))2 were using calculating BMI. Scale is continuous.

3. Change from baseline adherence to healthy lifestyles at 12 weeks, 24 months and 36 months. The Adherence to healthy lifestyle is measured using Likert scale with 5 point. The range were from 1 to 5, where 1=strong disagree - 5=strong agree. The adherence to healthy lifestyle questionnaires validity and reliability have been tested before (Kyngäs et al. 2000. The development of an instrument to measure the compliance of adolescents with a chronic diseases. Journal of advanced nursing 32 (6):1499-1506.

Parents outcomes:

1) Change from baseline adherence to healthy lifestyles at 12 weeks, 24 months and 36 months. The Adherence to healthy lifestyle is measured using Likert scale with 5 point. The range were from 1 to 5, where 1=strong disagree - 5=strong agree. The adherence to healthy lifestyle questionnaires validity and reliability have been tested before (Kyngäs et al. 2000. The development of an instrument to measure the compliance of adolescents with a chronic diseases. Journal of advanced nursing 32 (6):1499-1506.

Data analysis: Across-group comparison of baseline physical activity, BMI, gender and age were conducted for evaluable participants using ANOVA (Kruskal-Wallis test) for continuous variables and for categorical variables (eg. sex) we used Fischer´s exact test.

Inclusion Criteria:

• 13-16 years old,
• overweight or obese (weight for height >20% over normality)

Exclusion Criteria:

• mental health problems, long term illnesses.