There have been a few enquiries into bariatriccookery.com this last month about pre-op diets (I only wish there were more but funding, or lack of it, means only a few get NHS or privately-approved resources). The most pertinent question is do I need to do it; why; and what if I can’t adhere – I’ve failed at every other diet before?…. So here’s my very brief answer to these questions (if you have anything more pressing to ask then do email firstname.lastname@example.org or speak to your own bariatric team for answers!
It will have stressed to you, at various pre-op consultations, the need to follow a special pre-operative diet for about 2 weeks (but sometimes longer) prior to weight-loss surgery. After years of following and failing at diets, many patients understandably query their necessity. So are they necessary and why?
Well this special pre-op diet is not necessarily a specific weight-reducing diet (although many patients will record a weight-loss while on it) but has been designed to shrink the liver so that the surgeon can operate more easily and it also increases the chances of your surgery being performed laparoscopically (by keyhole). It’s not an optional diet but a compulsory one and is only intended for before surgery. It should not be followed after surgery or by anyone else.
Why do I need to follow this diet?
This diet is low in carbohydrate and fat. It will therefore reduce the glycogen stores in the liver (glycogen is a form of sugar stored in the liver and muscles for energy). This results in the liver shrinking in size and softening.
When performing bariatric surgery laparoscopically, the surgeon will have to lift the liver to access the stomach. If the liver is heavy, fatty and immobile, it is much more difficult for the surgeon to see and get access to the stomach. This could be a reason for changing to open surgery. Open surgery means a larger abdominal scar, which results in longer recovery and increased risks.
By following this diet, you are likely to lose weight before surgery but, more importantly, your liver will shrink and you increase your chances of having a safe operation.
It is important to stick to the regime you are given and for the stated time advised by your bariatric team. Don’t be tempted to have a special or larger ‘last’ meal the night before your surgery, as this will reverse the liver-reducing effects of the diet. If you feel like a last-ditch blow-out then have it before you start you pre-op diet!
What does the diet comprise and consist of?
This very much depends upon your surgeon, you and your medical history. If you have diabetes then flag this up to your team because you will need a different diet to a non-diabetic.
Some pre-op diets are principally ‘milk diets’ where milk is the main foodstuff along with other fluids (like tea, coffee and no-sugar flavoured water), a sugar-free jelly and salty drink allowance.
Other diets that may be recommended are low-fat, carbohydrate regulated (to about 100g per day) and moderate in protein. Patients are given a diet sheet with recommendations of foods and their quantities for such a regime. Both pre-op diets ask you to take a multi-vitamins and mineral tablet supplement every day too.
It is possible that you will experience headaches or feel ‘light-headed’ after starting this diet; this is quite usual and will pass in the first few days. What it will do is prepare you for an important journey ahead so is the start of something life-changing.