Bariatric Surgery Versus Non-alcoholic Steato-hepatitis

Roux-\&-Y Gastric Bypass (RYGB) involves the use of a surgical stapler to create a small and vertically oriented gastric pouch with a volume of 30 ml. The upper pouch is completely divided by the gastric remnant and is anastomosed to the jejunum, 75 cm distally to the Treitz's ligament , through a narrow gastrojejunal anastomosis in a Roux-en-Y fashion. Bowel continuity is restored by an entero-entero anastomosis, between the excluded biliary limb and the alimentary limb, performed at 100 cm from the gastrojejunostomy. Lifestyle modification counselling is provided to each patient.

The SG is created using a linear stapler with two sequential 4.8/60-mm green load firings for the antrum, followed by two or three sequential 3.5/60-mm blue loads for the remaining gastric corpus and fundus. The stapler is applied alongside a 48-Fr calibrating bougie. The resection line is performed avoiding the ''critical area'' by resecting the fundus 1.5 cm from the angle of His. Staple lines are buttressed with bovine pericardial strips. The resected stomach is grasped at the antral tip by a laparoscopic grasper and retrieved through one of the trocar sites. A methylene blue dye test by a nasogastric tube is routinely performed at the end of the procedure. The residual gastric remnant capacity is 60-80 ml. Drains are not routinely placed, and the nasogastric tube is removed at the end of the procedure. Upper gastrointestinal contrast (Gastrografin) study is performed on the first postoperative day. Lifestyle modification counselling is provided to each patient.

Resting calorie requirements will be calculated via the Harris Benedict equation (24) and an activity factor, and subjects will be instructed not to change their activity level other than that suggested by physicians during the study. The diet will contain 1/3 kcal less than the calculated energy expenditure and 30% fat of which 10% saturated, 55% lower glycemic index carbohydrates and 15% proteins. The participants will be encouraged to gradually increase their walking to achieve 10,000 steps per day. A moderate intensity physical activity program of 1 hour of aerobic exercise 2-3 hours per week will be recommended to all subjects. Their physical activity will be assessed by IPAQ-SF.