This study will examine whether providing physical activity counseling and guidance to patients post bariatric surgery, along with long-term personal follow-up for six months after the surgery, may increase the level of physical activity, and it's effect on anthropometric and functional measures.

Bariatric surgery is considered to be most effective in treating morbid obesity for patients with BMI≥40 or BMI≥35 with comorbidity for obesity.

postoperative weight loss following any type of bariatric surgery is largely dependent on the extent to which patients can make and sustain changes in their eating habits and activity level. Adopting physical activity habits can help to optimize outcomes after bariatric surgery, such as contributing to the rate of weight loss after the surgery and maintain lean body mass.

In order to successfully implement a behavioral change regarding the adaptation of healthy lifestyle habits in obese patients, it is vital to promote physical activity counseling after the surgery, and to find an effective intervention that can support habitual physical activity.

The aim of this trial is to examine the effect physical activity counseling after bariatric surgery on the amount and intensity of activity performed, quality of life, anthropometric and functional measures during the first year after surgery.

Up to eighty Participants will be recruited for the trial, and will be randomly assigned to one of the two study arms (Control, Intervention). The intervention group will receive physical activity counseling and guidelines for the following six months after the surgery.

All participants will receive a pedometer to track daily steps for 7 days at different time points before and after the intervention. Additional Measurements will be taken at a pre-surgical baseline assessment and throughout the trial, and will include anthropometric measures (Weight, BMI, and body composition) and functional measures (Handgrip, 6-minute walk test, chair stand-up test).

All participants will fill out a the 7-day international Physical Activity questionnaire, Self-efficacy for physical exercise scale, and SF-36 questionnaire, before and after the intervention.

Inclusion Criteria:

• BMI ≥ 40 kg/m2 or 35 kg/m2 with comorbidities
• 18 to 50 Years old
• Patient is suitable according to the pre-operative evaluation standards to undergo Bariatric surgery
• Speaks Hebrew/Arabic fluently

Exclusion Criteria:

• Cognitive decline or severe psychiatric or mental illness
• Patient undergone bariatric surgery in the past
• Pregnancy or Breastfeeding
• Orthopedic disease that limits training and mobility (such as severe arthritis, injury or fractures)
• Heart disease with a risk to exercise (heart failure, severe aortic stenosis, uncontrolled arrhythmia, and acute coronary syndrome)
• Moderate /severe lung disease or COPD with FEV1 / FVC <70% on a pulmonary function test