Patients that have a weight loss surgery coming up are made to follow a pre-operative weight loss diet. Such a diet serves two purposes. One, it demonstrates to the doctor that you are indeed capable of following a strict dietary regimen. In the absence of a disciplined diet schedule, surgery by itself cannot offer a long-term solution to keep the weight down. Two, it gives you an opportunity to lose as much weight as you can in a natural manner. Every pound thus lost makes the surgery that much easier on you and also safer.
A pre-op weight loss diet is often to lose a targeted amount of weight, maybe 10% of the total weight.
Studies show that patients who meet or exceed this target benefit more from the surgery. They stay in the hospital for shorter duration compared to others and their weight loss over a given period of time is also greater. Such diets are high in protein, which means that you do not lose muscle, only fat. A big physiological change is that the size of the liver decreases with even 10% – 15% weight loss. This not only makes laparoscopic surgery easier but also improves liver health, which is vital for fat metabolism. In fact, shrinking the liver before the surgery is one of the objectives of this diet and is often achieved by putting the patient on a purely liquid-only diet.
Normally, a pre-op weight loss diet is only for a fortnight or so; but if the surgery is a complicated one or the weight-loss target is high then you may have to be on this diet for as much as three months. A duodenal switch requires diet over a longer period, lap-band patients can diet for a shorter duration.
Usually, the diet will eliminate high-fat food items, fried foodstuffs, and sugary items. These are substituted by fruits, vegetables, protein, whole grain bread, and similar items. Thin soups are preferred. Milk products are from toned and skimmed milk. Instead of sugar, sugar substitutes are used.
The period of a pre-op diet is also a time for the patient to assess his own mental and physical preparation to adhere to a post-op lifestyle. What you do during the pre-operative phase will determine the success of the entire weight-loss program. If your counselor advocates surgery during the period before operation then, by all means, do exercise. Burn as many calories as you can. It’s a given that you will have to stop smoking to improve your health and chances of a quick recovery. The nutritionist may ask you to abstain from certain over the counter medications that can act as blood thinners or appetite stimulants.
As an aside, if you have health insurance that covers surgery, check the implications of a pre-op diet on such surgery-related cover. Sometimes, a weight-loss diet program before surgery is mandated by insurance companies.
These pre-op diet programs will vary with the hospital; you should gather references from those that have successfully undergone such a program prior to surgery.