The pre-op diet: it’s not as bad as you think!

The pre-op diet for a sleeve gastrectomy is important as it reduces the fat around your organs and reduces the size of your liver, making the surgery easier, quicker & reducing the risk. As your stomach sits behind your liver, your surgeon needs to move it out of the way to get to your stomach so the smaller the liver the better! In fact, if your liver is too big, your surgeon may decide not to go forward with the operation, so it’s extremely important that the pre-op diet is done properly.

Doing a VLCD (very low calorie diet) as the pre-op diet deprives your body of carbohydrates and forces your body to burn its own fat as fuel. When fat is broken down for energy it is made into ketones (a process called ketosis). This is a natural appetite-suppressing process, so after the first few days you won’t feel too hungry. If you eat too much or too often, particularly  carbohydrate, fat loss will not occur as your body will still be burning carbohydrate for energy.

The VLCD we use in our clinic is Optifast although there are other options.  Depending on your weight and any medical issues such as fatty liver, your surgeon will advise you to have Optifast for 2-6 weeks prior to surgery. Don’t worry though! It’s not just shakes all day and you can get pretty creative with the other things you can eat… I also see clients do really well with this as the mindset is different – it’s not just another diet. Instead, you have a set time frame, you have a good reason to do it and if you don’t, there is the risk that your surgeon may not go through with the surgery!

What is Optifast?

Optifast is a medically formulated meal replacement. It comes in milkshakes, bars, desserts and soups. You can mix and match whichever varieties you like best. Optifast can be purchased at your local pharmacy. Preparation is simple: just mix the sachet with water as directed. The bars require no preparation.

What can’t I eat?

AVOID CARBOHYDRATE FOODS

Stay away from anything that contains carbohydrate whether it’s natural sugar (fructose and lactose), added sugars or starch. Eating carbohydrate will prevent ketosis occurring and you won’t get the desired effect on your liver. Do not eat:

• Starchy vegetables like potato, sweet potato, pumpkin and corn
• Grain foods like rice, cereal, pasta, quinoa, bread, oats and muesli bars
• Legumes like chickpeas, lentils and kidney beans
• Fruit
• Dairy (sorry – the milky coffee has to change to a black one +/- some artificial sweetener)
• Sweets or any other food with added sugar or honey like chocolate, biscuits, cake or lollies

What can I eat?

Each day you’ll have low-carb vegies, as well as soups and maybe some additional protein if you need. **If you have to do Optifast for longer than 2 weeks before surgery, usually the first weeks will be a modified version with 2 optifast products and a meal of protein and vegies, but check with your dietitian first. Check out this list of allowed foods from the Optifast website, just make sure you don’t include anything from the fruit/dairy section. I’ll also have some pre-op suitable recipes coming your way, soon, so keep an eye out.

A sample day:

Breakfast

• 1 serve of Optifast (e.g. Optifast milkshake, soup or bar)
• Black tea or coffee – no milk, no sugar

Lunch

• Clear broth (if desired)
• 1 serve of Optifast (e.g. Optifast shake, soup or bar)
• 1 cup salad (from list) with dressing (from list)
• Water/black tea or coffee/diet cordial/diet soft drinks
• NB – some people like to spread these foods over the day so they get snacks.

Dinner

• 1 serve of Optifast (e.g. Optifast shake, soup or bar) or 100-200g protein (meat, fish, chicken, tofu, eggs) if required**
• 2 cups steamed vegetables (from list)
• Water/black tea or coffee/diet cordial/diet soft drinks
• Diet jelly (if desired)

Extras:

• DRINK: Drink at least 2 litres of water (8-10 glasses) each day. This may include water, mineral water, diet soft drink and cordial and black tea or coffee. Drink plenty of water between meals.
• FIBRE: As Optifast is almost completely absorbed by your body there will be little residue left in your gut, so you may not have regular bowel motions. Start a daily fibre supplement like Benefiber or Metamucil (no added sugar) to reduce the risk of constipation.
• OIL: Add 1 teaspoon of oil to your vegetables as a dressing or in cooking. Olive, vegetable, sesame, avocado and macadamia oils are all good options.

If you’re hungry: have more protein or vegies from the list. Your dietitian may also ask you to have an additional serve or two of protein depending on your size, so ask them before you begin.

Mix up the taste!

If you really cannot tolerate the VLCD shakes alone, try the following:

• Use ice or iced water when you mix the shakes and a blender to really mix in the powder
• Mix the vanilla shake with cold chai or fruit-infused herbal teas instead of water
• Mix the chocolate shake with cold peppermint tea instead of water
• Add a few strawberries (~50g only)
• Sweeten them with a little artificial sweetener like Equal or Splenda
• Cook your vegetables (from the list) and add them to the Optifast soup.
• Add a teaspoon of curry powder to the Optifast soup to give it a little extra flavour.

A note for those with diabetes…

As you will not be getting much sugar from your food, it is likely your medications will need to be reduced or stopped. Please inform your GP or endocrinologist of your plans to start Optifast. If you do experience a hypo, treat it with a small amount of rapidly absorbed sugar e.g. juice or jelly beans.

I can’t tolerate Optifast!

If you experience any constant diarrhoea or feel you are intolerant to the Optimist program, please get in touch with your dietitian for advice and/or to organise an alternative if need be. The Optifast bars, desserts and chicken soup varieties are lowest in lactose so may be a better option than the shakes. If you have any other intolerances or allergies, check out the Optifast FAQ page here.

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