Pre-operative Very Low-calorie Protein-based Versus Hypocaloric Enteral Nutrition

Pre-operative Very Low-calorie Protein-based Versus Hypocaloric Enteral Nutrition to Improve Intra- and Post-operative Outcomes of Severely Obese Patients Undergoing Bariatric Surgery

Pre-operative weight loss can reduce the risk intra- and post-operative complications but no optimal pre-operative weight loss strategy has been investigated. Very-low-calorie diets (VLCDs) were proven to results in higher metabolic improvements in the short-term than balanced, hypocaloric diets. Therefore, the aim of the study is to investigate whether a VLCD results in lower intra-and post-operative complications compared to a hypocaloric diet. However, to achieve a optimal compliance in patients having experienced multiple dietary intervention failures, administration of the intervention will be performed by the enteral route using a naso-gastric feeding tube.

Bariatric surgery is an important treatment strategy for obese patients having failed multiple diet-induced weight loss attempts. On the other hand, severly obese patients have also a high risk of both intra- and post-operative complications. Pre-operative weight loss can reduce these risks but no optimal pre-operative weight loss strategy has been investigated. Very-low-calorie diets (VLCDs) were proven to results in higher metabolic improvements in the short-term than balanced, hypocaloric diets. Therefore, the aim of the study is to investigate whether a VLCD results in lower intra-and post-operative complications compared to a hypocaloric diet. However, to achieve a optimal compliance in patients having experienced multiple dietary intervention failures, administration of the intervention will be performed by the enteral route using a naso-gastric feeding tube.

Inclusion Criteria:

• patient candidate to laparoscopic bariatric surgery (gastric bypass or sleeve gastrectomy) after multi-disciplinary pre-operative evaluation
• Availability to long-term post-operative follow-up
• Normal kidney function serum creatinine ≤ 1,2 mg/dL and glomerular filtration rate ≥ 90 mL/min
• Normal liver function (aspartate amino-transferase and/or alanine amino-transferase and/or gamma glutamyl transferase < 2 x N)
• written informed consent

Exclusion Criteria:

• age <18 or >60 anni
• serum creatinine >1,2 mg/dl
• liver failure (Child-Pugh ≥ A)
• insuline-dependent diabetes mellitus
• atrioventricular block with QT > 0,44 ms
• Cardiac arrythmias
• Moderate-severe cardiac failure
• Hypokaliemia
• Chronic diarrhoea or vomitus
• 12-month previous cardio-vascular disease
• pregnancy and/or lactation
• current/previous neoplastic disease
• psychiatric disorders
• know gastro-intestinal diseases
• other controindications to enteral nutrition
• moderate-severe hypo-albuminemia (<3.0 mg/dL)
• 6-month previous diet-induced weight loss
• intragastric balloon
• unavailability to planned measurements