Pre-operative Diet For Sleeve Gastrectomy & Gastric Bypass Surgery

Before you have a Sleeve Gastrectomy (SG) or Gastric Bypass (RYGB) operation, you will have been seen by our dietitian and clinical psychologist, who will have advised you regarding nutrition and eating patterns to optimise the results of your surgery. It is important to make sure the food you eat is nutritious (preferably home cooked), with an emphasis on fresh vegetables, whole grains and lean protein. Try to have regular meal times, and measure your portion sizes so you get used eating a fixed amount (avoid second helpings!). Eat slowly, and chew your food well – this will help you feel full at the appropriate time, and make you less likely to want a second helping. Snacks should definitely be avoided, as the tendency to graze is a contributory factor in gaining weight. You will find it easier to avoid grazing if food types like crisps, biscuits and chocolate are not in the house at all, so it helps enormously if your family are willing to support you with this. Alcohol also contains a lot of calories, and often makes people less careful about avoiding snacks, so do limit your alcohol intake as far as possible once you have decided you would like a SG or RYGB.

For the two weeks prior to your operation, you will need to follow a ‘liver shrinkage diet’ and you will get information on this from our dietitian. This is really essential to do according to the instructions, as otherwise there is a risk that it may not be possible to do your operation on the day. The liver shrinkage diet is a very low calorie diet, which is carbohydrate and fat free. Cutting out carbohydrate for two weeks makes the liver use up its glycogen and fat stores, and therefore it shrinks, becoming thinner and more floppy. Many women lose 4-6 kg, and men typically lose 6-8 kg during this time, so it is a very effective diet, but not sustainable for long term weight loss as it is very restrictive.