Diet after gastric sleeve, bypass or banding:

Bariatric surgery is for the purpose of weight loss and may involve reduction of the size of the stomach and/or modifications to the intestine to limit food absorption. Common surgeries include; gastric sleeve, bypass and banding.

Most weight loss procedures are performed via keyhole surgery (laparoscopically) and are typically performed on those with a body mass index (BMI) >35.

gastric sleeve diet plan by portion perfection

What you need to know about pre and postoperative nutrition

Bariatric surgery procedures require patients to undergo strict pre and post operation dietary changes to ensure successful weight loss is achieved; the surgical procedure itself is only half the job.

Prior to surgery, the patient will need to go on a typically liquid based pre-op diet, involving a shake diet along with free vegetables. The main goals are to remove fat from the liver, reduce post-surgical pain and potentially reduce surgical time. When there is fat in the liver, the organ is larger, more fragile and bleeds easily.

When it comes to the post-op on a post gastric sleeve diet plan offered dietitians, like all weight loss plans, diet and exercise are important for success. Even after such a surgery, energy output still needs to exceed energy input to achieve weight loss.

At Great Ideas in Nutrition, we can help you with an after bariatric surgery plan, providing assistance with fluid and puree regimes soon after surgery and long-term eating guides. With all bariatric surgeries, it is common to achieve maximum weight loss at approximately 12 months post surgery and sometimes experience weight regain at 2 – 5 years post surgery. Our dietitians recommend a maximum meal volume of 1 cup post-surgery to ensure the maintenance of the restrictive component of the surgery.

Phases of gastric sleeve surgery

gastric sleeve diet
  • Phase 1: Clear liquids

  • Immediately after bariatric surgery, nausea and vomiting are normal because the stomach is recovering from the procedure. Therefore, it is essential to stay hydrated and promote healing. This phase can last up to a week.

  • Phase 2A: Full liquid

  • Around two weeks after surgery is when patients can introduce protein back into their diet. A sugar-free protein shake is necessary during this time, alongside the clear liquids from phase 1. During this phase it is important to avoid sugar, fat and solid food. Caffeine and fizzy drinks should also be avoided to prevent complications.

  • Phase 2B: Pureed foods

  • After 3 weeks, patients can begin to eat soft, pureed foods. These foods should be high in protein to aid in the healing process. Again, caffeine, sugar and fat should be avoided. It is also important to eat slowly and ensure foods are smooth, not chunky.

  • Phase 3: Soft foods

  • This phase introduces solid foods back into the diet. High protein, soft foods such as well-cooked fish and chicken are perfect during this time. Patients should continue to focus on hydration and avoid nutrient poor food choices. Caffeine may be reintroduced at this phase.

  • Phase 4: Stabilisation

  • This stage marks the commitment to a new healthy lifestyle needed to prevent unwanted weight gain in future. Our team specialise in helping bariatric patients implement long-term eating patterns which encourage a healthy lifestyle. Having the right tools to succeed is essential.

Gastric Sleeve Diet FAQs

There is nothing you can’t eat. It’s more about how much, how often and the way in which you eat. For example chewing well, keeping fluids separate and eating slowly.

For some people a major change to the type of food is required to provide a healthy intake. We often recommend a reduction in carbohydrate based foods such as rice, pasta and potatoes at main meals to leave sufficient space for protein and vegetables. It’s also a good idea to ensure snacks provide vital nutrition which may mean substituting fruit, dairy, vegetables or nuts for less healthy choices.

Sweetened beverages provide calories without significant nutritional value so are best avoided before and after any weight loss surgery. Carbonation may or may not be a problem causing burping and pain from trapped gas. This depends on how easily the gas can escape. It is very unlikely that even trapped gas would expand or stretch the stomach as some sites propose.

Although you can expect to lose weight quickly, it will not happen overnight. Around 3 months is when you will see the fastest drop in weight. By 6 months, weight loss will begin to level out and after 1 year, most patients should be close to their goal weight, though this may take a bit longer for some.

White pasta is best to be avoided after a gastric sleeve due to a relatively poor nutrient profile and high calories. Pastas made with 100% whole grains provide B vitamins, fibre and complex carbohydrates, however due to their high calorie count, they are best to be eaten in small amounts to ensure enough room is left for free vegetables and protein. Lentil pastas are high in fibre and minerals; however they too should be eaten in small amounts.

Immediately after surgery your daily caloric needs will decrease to around 400 calories for about 2 weeks, increasing to 500 from weeks 2-8. However, from 2 months and beyond your caloric intake should not exceed 1000 calories per day. Due to the number of calories you can consume, a variety of low calorie, nutrient dense foods should make up your diet. Portion control is key to success after surgery. Never eat past the point of fullness.

Have a question?

Resources for people on a gastric sleeve diet (incl. gastric sleeve recipes)

Through careful analysis, Amanda Clark has determined our most commonly prepared and bought meals and foods. Portion Perfection for Bariatrics has been designed for people around the globe, having undergone gastric sleeve, bypass or banding surgeries.

The Complete Pack includes the Portion Perfection for Bariatrics Book (a gastric sleeve cookbook), Portion Perfection Bariatric Plate and Bowl in either porcelain or melamine, the 4 Week Weight Loss Menu Plan and the Healthy Snack Bible. Portion Perfection also produces a handy Free Vegetables cookbook – great for the pre-surgery regime and long-term eating – and handy snack containers in the right portion size.

Amanda Clark (Founder of Great Ideas in Nutrition) has joined with US nutrition expert Dr Susan Mitchell to produce the free podcast Beyond Bariatric Surgery. Together these professionals deliver fortnightly content that is practical and valuable to the bariatric surgery community. You can find the podcast on your favourite podcatcher.

Enquire about your gastric sleeve diet pre and post-op diet needs today!

Great Ideas in Nutrition, specialists in gastric sleeve surgery diet plans