Randomised Trial of Intensive Behavioral Lifestyle Intervention Versus Usual Preparation for Bariatric Surgery

Obesity is a complex, multifactorial pathology that has major public health importance. Lifestyle modification is the cornerstone of all obesity treatments, including surgery. Throughout the non-surgical treatment options, high-intensity, on-site comprehensive lifestyle intervention has demonstrated the best efficacy in obtaining weight loss, but with a risk of progressive weight regain, after 6 months (1). In obese adults, bariatric surgery produces greater weight loss and weight loss maintenance than the conventional medical treatment and lifestyle intervention (1). There is no consensus on whether combining these two approaches (i.e. high-intensity, on-site comprehensive lifestyle intervention and bariatric surgery) results in enhanced weight loss or more sustainable outcomes. The present randomized trial aims to answer this question. Patients preparing for bariatric surgery will be randomized between two groups. The first group will receive the usual care as recommended by the French Health Authority ("Haute Autorité de santé"), including 6 months of endocrine and nutritional follow-up and educational intervention. The second group will receive a high-intensity, 4 weeks on-site comprehensive lifestyle intervention, including prescription of a moderately reduced-calorie diet, a program of increased physical activity, and behavioral management. The patients from both groups will then be operated on and followed for at least 2 years. Complete work-up, including clinical examination, comorbidity assessment, MRI of the liver, thigh and abdominal fat, 6 minutes' walk test, quality of life questionnaires will be performed at the begging of the follow-up, after the preparation (usual care or intensive) and 2 years after surgery. Clinical and biological assessment will be performed regularly after surgery, and technical details from the bariatric interventions will be analyzed in order to assess the eventual facilitation of the gestures in the intervention group.