Impact of Bariatric Surgery on the Gut Environment (IMPORTUNE)

• Surgery patient group was recruited at the University Hospital Leuven.
• Obese control group was recruited at the Obesity Clinic of the University Hospital Leuven.
• Normal and overweight control group was recruited among the employees and family members from employees of the University Hospital Leuven.

Inclusion Criteria:

• Surgery patients (toxicity and protein assimilation) : BMI > 40 kg/m² or > 35 kg/m² if combined with either obstructive sleep apnoea syndrome, high blood pressure not controllable with 3 different medications or type II diabetes, (3) exclusion of other underlying causes of obesity by an endocrinologist, (4) having tried to lose weight on a non-surgical way for at least 1 year without result and (5) a positive advice from a multidisciplinary team consisting of a surgeon, endocrinologist, psychologist and dietitian.
• Obese control group in weight loss program (toxicity) : obese but otherwise healthy patients on a weight loss diet (BMI > 30 kg/m²) in the context of the weight-loss program organised at the Obesity Clinic of University Hospital Leuven.
• Control group (protein assimilation) : normal weight (BMI 25-30 kg/m²) or overweight (BMI 25-30 kg/m²).

Exclusion Criteria:

• Intake of antibiotics 1 months before the start of the study. Pre-and probiotics, laxatives and anti-diarrhea drugs 2 weeks before the start of the study.
• Surgery patients and control group (toxicity) : Gastrointestinal disease or major abdominal surgery in the past (except from appendectomy and cholecystectomy).
• Surgery patients and control group (protein assimilation) : Lung, liver, kidney and gastrointestinal disease or major abdominal surgery in the past (except from appendectomy, cholecystectomy and bariatric surgery). Vegan, vegetarian, lactose-or gluten-free diet. Pregnant or lactating women and subjects who participated in the last year in a study with irradiation exposure.