In the final month, I prepare the patient for his or her preoperative, fasting diet. The preoperative diet differs significantly from the Pound of Cure style of eating that we’ve been working on. The Pound of Cure eating style is designed as a way of eating that can be maintained life long and prevents weight regain after surgery. The preoperative diet is designed to induce rapid, short term weight loss. This weight loss can’t be maintained over the long run, but this is irrelevant as you approach surgery.
The goal of the preoperative diet is to trigger rapid weight loss over a short period of time. When you lose weight quickly, it depletes the liver of fat and glycogen which makes the surgery easier to perform. The most effective way to lose weight quickly is by severely restricting your calorie intake. The pre-operative diet limits your calorie intake to around 800 calories per day with very little carbohydrate intake. The easiest way to do this is through the use of meal replacement protein shakes.
There are hundreds of brands of protein shakes available however, despite the marketing claims, they are incredibly similar to each other. The most predominant source of protein comes from whey which is derived from milk. Despite this, those patients with lactose intolerance are usually able to tolerate whey protein well since the lactose is removed during the processing. Some of the less expensive or “vegan” shakes use soy which, I think, is a lower quality protein. Soy can stimulate estrogen receptors (which are present in both men and women) and large doses can create hormonal irregularities that may interfere with weight loss. Recently, shakes with pea or peanut protein have become popular but probably do not convey a significant advantage over whey protein shakes. These “vegan” shakes are typically two to three times as expensive as those that use whey protein. Whatever protein shake you choose should contain 15-20 grams of protein, less than 3 grams of sugar and contain less than 200 calories each.
I also allow unlimited calorie free drinks (anything less than 10 calories per serving) on the pre-operative diet which goes directly against my teaching of the dangers of artificial sweeteners. The preoperative diet is difficult to follow and is only a short term program. I’ve found that eliminating sugar free drinks makes this diet exceptionally difficult to follow and decreases compliance. Again, the goal of the preoperative diet is to lose weight quickly over a short period of time in preparation for surgery.
Finally, I allow unlimited green vegetables (except avocadoes) on the preoperative diet. You can use unlimited seasonings and spices, but no butter or oil. As we’ve discussed, these vegetables facilitate weight loss and will help your body from entering a starvation prevention mode during the severe calorie restriction imposed by the diet.
For some patients, tight compliance with the preoperative diet is critical to the patient’s safety. For other patients, it is much less important. A very small percentage of patients have severe fatty liver disease that interferes with the safety of the operation. Men, high BMI patients, diabetics and those whose weight is concentrated in their belly, rather than their butt and thighs are more difficult to operate on. A preoperative diet, often for two weeks or more is critical to safe surgery. For those patients who don’t fall into the higher risk group, I limit the preoperative diet to a less restrictive program, often for only one week. In the lower risk patients, I also allow them to follow the Pound of Cure “Metabolic Reset Diet” described in detail in my first book.
I’ve listed the instructions I provide for my patients, but ask that you defer to your surgeon if he or she uses a different pre-operative diet.
All Men and Women with a BMI >50
- Four Protein Shakes every day
- Every morning 1 sugar free fiber drink (Metamucil or similar)
- Take your Bariatric Vitamins daily
- Unlimited Calorie Free Liquids
- Unlimited green vegetables (except avocados)
- Start 2 weeks prior to your surgical date (or longer if instructed)
All Women with a BMI <50
- Two Protein Shakes every day (one for breakfast, one for lunch)
- A healthy, low carbohydrate dinner (<400 calories)
- Every morning 1 sugar free fiber drink (Metamucil or similar)
- Take your Bariatric Vitamins daily
- Unlimited Calorie Free Liquids
- Unlimited green vegetables (except avocados)
- Start 1 week prior to your surgical date
- It is acceptable to follow the Metabolic Reset Diet instead