Diet Before Surgery (The Optifast VLCD Diet)

Written by Ali Zarrouk on .

Your journey to a more optimal weight starts before the sleeve gastrectomy operation itself begins. Our experience and that of many other bariatric surgeons has shown that significant weight loss before the surgery increases the efficacy and safety of the procedure by reducing the size of the liver and accumulations of fat around the stomach.


Why is it important to lose weight before surgery?

• Reduces fat around the stomach. This assists in exposure and identification of important anatomical landmarks.
• Shrinks the size of the liver which otherwise can be in the way and obstruct the view.
• Improves respiratory mechanics
• Increases patient’s compliance and tolerance to dietary changes after surgery
• Reduces operating time and postoperative risks such as deep venous thrombosis, embolism and chest infection.
• Reduces pre-existing metabolic abnormalities caused by obesity including hypertension, hyperlipidaemia, insulin resistance, increased risks for blood clots and sleep apnea.
• Improves physical function and mobility postoperatively.
• Improves the outcome of surgery and results in greater weight loss in the long term.

This is why Dr. Zarrouk recommends that you follow the Optifast® VLCD diet plan for two to three weeks before your sleeve gastrectomy surgery.Optifast


What exactly is the Optifast® diet and how does it work?

Optifast is a medically formulated meal replacement diet and works by keeping your caloric intake below 800 calories per day. It has all the minerals and vitamins your body needs but with a minimal number of calories. Thus your body is forced to break down its own stores of fat to provide that energy.

As the stored fat is broken down, chemicals known as ketones (which act as appetite suppressants) are released, allowing you to feel satisfied. In other words, even though you will be eating far less while on the Optifast, you won't necessarily feel hungry all the time as you might with other fasting-type diets. If you’re wondering why you can't just take Optifast and avoid the surgery, this diet is unsuitable for long-term weight loss because over prolonged periods of time the diet negatively disrupts your normal eating habits. However, for the short period of time before your surgery, the diet provides an ideal first step towards preparing for a healthier and less obese you.

Is Optifast® Suitable for diabetics?

The Optifast® VLCD is safe for diabetics, with some changes to the list of approved vegetables given below. If you are on insulin or tablets for diabetes, you may need to adjust your medications to prevent low blood sugar. Therefore, please discuss this with your GP or your endocrinologist before beginning the diet and monitor your blood sugar carefully while on the diet.

What is the basic Optifast® VLCD program?

The Optifast plan is based on eating three "meals" per day, at your normal meal times:

• Breakfast – one Optifast milkshake, with black tea or coffee.
• Lunch – one Optifast bar, with one cup of salad served with low-calorie dressing such as vinegar, lemon, seeded mustard, or non-fat plain yoghurt as a substitute for mayonnaise.
• Dinner – one Optifast Chicken Soup, with one cup of steamed vegetables and one serving (120 g for women, 210 g for men) of lean beef, veal, pork, lamb, fish, or chicken breast.
• Between meals or for snacks – strained broth, diet cordial or soft drinks, herbal tea, soda water, black tea or coffee (to which you can add 50 ml of low-fat milk and/or sweetener).
• Drink lots of fluids all day – at least 2 litres of water or other approved fluids.
• Other non-calorie, non-energy foods – you can supplement these meals with foods that provide no caloric energy, such as diet jellies, strained broth, unflavoured mineral water, diet soft drinks, and/or an additional two cups of the vegetables listed below, served either steamed or raw, but without butter or margarine, using lemon, lime, herbs, or vinegar to season them.

How to prepare the Optifast meals?

You prepare the basic Optifast meals by adding one package of Optifast® VLCD to 200 ml of cold or warm water and then shaking it or placing it in a mixer. You may use more water if you want, but do not use boiling water. The types of Optifast products available to "spice up" this basic routine include several types of milkshakes (chocolate, vanilla, coffee, and strawberry), soups (chicken and mixed vegetable), and dessert bars (chocolate, berry crunch and cappuccino).

For dinner, you can also add variety by preparing the lean meats with the vegetables, in dishes such as a chicken, beef, fish, or prawn stir-fry. You may also create combination meat and vegetable skewers, or oven-bake/roast the meats with roasted capsicum or zucchini. You can also add your allowance of tuna, ham, grilled chicken, or salmon to a dinner salad. Twice a week, you may substitute two large eggs or 60 g of low-fat Cheddar cheese for 60 g of the meat, fish, or chicken.

Certain fruits are permitted (but only one per meal) and in the following quantities – one (1) apricot, apple, lime, peach, mango, medium orange, small pear, or slice of pineapple; 200 g of strawberries, 100 g of cooked rhubarb, 100 g of grapes, 120 g of plums, or 5 prunes. Avoid all other fruits including bananas.

Which vegetables can you eat while on the Optifast diet?

The vegetables permitted while on the Optifast diet should be fresh, not canned, and low-starch, such as :

asparagus                   celery                lettuce                  cauliflower              tomatoes   
green beans cucumber silver beets tomatoes capsicum
eggplant snow peas Bok Choy beetroot artichokes
spinach leeks squash broccoli cabbage
alfalfa sprouts mung beans Brussels sprouts shallots watercress
mushrooms zucchini onions chives carrots
shallots radishes      

You may eat any of these vegetables raw, steamed, or prepared in a stir-fry or dry-roasted, as long as you add no additional fat or calories. You can flavour them with any of the following herbs, spices, and condiments: salt, pepper, vinegar, lemon, coriander, chives, chili, garlic, mint, basil, parsley, curry, and ginger.

Which foods should you NOT eat while on the Optifast diet?

It is very important that you do not eat any of the foods listed in this section, because consuming even small quantities of them can significantly interfere with the Optifast diet and its weight-loss goals. In general, you should not eat foods that contain either flour or sugar. This includes breads, cakes, biscuits, chocolate, nuts, lollies, ice cream, pasta, sweets, pastries, snack foods, breakfast cereals, rice, thickened sauces, foods that have been deep fried or battered, takeaway foods, or noodles. Although the vegetables listed in the section that precedes this one are acceptable, you should not eat high-carbohydrate vegetables such as potatoes, sweet potatoes, sweet corn, green peas, parsnips, and legumes such as beans or lentils. You should avoid canned vegetables because they often contain added sugar.

You should not drink alcoholic beverages of any type. Other beverages that you should not drink include non-diet soft drinks, milk, fruit and vegetable juices, yoghurt or yoghurt drinks, flavoured mineral water, or powdered milk drinks.

What to expect during the first few days of the Optifast diet?

It is normal to experience some hunger at the beginning of the diet, but this usually goes away within a few days as your body becomes used to burning its own fat supplies to produce energy and transitions into ketosis. In addition, during the first few days of the diet you may experience some fatigue, irritability, dizziness, a lack of concentration, and possibly nausea or headaches. In some people, the production of ketones results in bad breath, but if you notice this you can alleviate it by chewing sugar-free mints or sugar-free chewing gum.

Take Benefibre or MetamucilBenefiber

To avoid constipation and to maintain proper bowel movements, you should stock up on the soluble fibre supplement such as Benefibre or Metamucil before you begin the Optifast program, because the Optifast program does not contain much fibre.



Contact Us

Suite 13, Level 1
Campbelltown Priv Hospital
42 Parkside Cres
Campbelltown 2560 NSW

+02 4625 4745

+ 02 4625 7335