A pseudo-randomised dietary intervention to evaluate the effects of a high protein diet on weight loss, body composition and other health outcomes in obese individuals who have gastric banding surgery.

The intervention involves a high protein diet for 26 weeks (6 months) following surgery. The intervention diet has been designed to provide approximately: 4500-5000kJ, 90-100g protein, 110g carbohydrate and 30g fat per day. This provides a macronutrient composition of approximately 35% protein, 40% carbohydrate and 25% fat. Participants will commence the intervention within 3 weeks of having surgery and according to clinical assessment. The intervention includes high protein food and drink choices and a powder-based whey protein supplement. Participants will be asked to have 3 level tablespoons of the supplement daily, providing approximately 12g of protein per day. The supplement can be mixed with regular foods and drinks and either consumed as a dispersed dose (eg one tablespoon three times per day) or as one 3 tablespoon dose, determined at the convenience of the participant. Participants will also continue to receive usual dietetic care in addition to the research intervention. Usual dietetic care consists of regular follow-up with a gastric banding dietitian, who provides individualised advice on food, nutrition and activity as appropriate for gastric banding. This will be administered via face-to-face and telephone consultations (of approximately 30 minutes duration) which will occur approximately every 2-6 weeks after surgery. Specific frequency and duration of consultations is determined by the gastric banding dietitian according to individual need.