Pre and Post Gastric Sleeve Diet

Pre-Surgery and Post Gastric Sleeve Surgery Nutrition: How Will Bariatric Procedures Affect Your Diet?

We have erratic meal times, readily available junk food and superbly busy lives. Hence, for many of us, it’s increasingly hard to lose weight or keep lost kilos from coming back. To make matters worse, weight gain often sneaks up on us. Many of us don’t even realise we are putting on weight until quite late in the gaining cycle. So if you’ve had weight loss surgery, or are about to have it, what changes do you need to make in your daily eating plans to optimise your results? In this blog, we discuss both the pre-gastric sleeve and post-gastric sleeve diet.

Below is an overview of what many consider one of the best diets to follow after having weight loss surgery.

Are you struggling to lose weight to improve your health?

bmi calculator, obesity, healthy bmi,

If you’re on the high BMI scale of obesity, you may end up researching your weight loss surgery options.

  • When nothing in our beloved wardrobe fits anymore, including our stretchiest slacks or leggings – a near panic can set in.
  • Wanting or needing to reduce excess weight quickly goes through our minds.
  • IF not OUR minds, then the minds of our General Practitioners or Endocrinologists, who tend to like to remind us of the detrimental health repercussions of being overweight.
  • It’s then that some of us struggling with a high BMI or obesity level weight problems consider weight loss surgery, medically called Bariatric Surgery.

We are under near-constant assault from junk food options and fast food chains. How are we ever going to keep our weight in check, even following the best eating plans after having weight loss surgery?

Pre and Post Gastric Sleeve Diet and Eating after Weight Loss Surgery

  • Whether you choose a gastric sleeve, gastric band, lap band, a gastric bypass or other weight loss surgery procedure, you’ll need to make changes in how you eat
  • You need to make these diet changes both before and after your gastric procedure (pre and post-gastric sleeve diets)
  • And whatever surgery you choose, if you lose over 20 kilos of weight, you are likely going to need excess skin excisions and body contouring surgery. This helps reduce skin fold problems associated with sagging skin after losing a lot of weight.

Why is obesity such an issue in today’s communities? And what diets are best to overcome obesity level weight concerns?

  • With busy lives, sugar-laden drinks and fast-food availability
  • There are also “bulk buy” food stores
  • A lack of outdoor activity, due to laziness, overworking and technology (Netflix, computer games and/or social media)
  • These factors and other lifestyle and meal habit changes have led to a national epidemic of OBESITY in Australia

Unfortunately, it’s not as easy to lose weight as it is to gain weight.

Once we get to an unhealthy Body Mass Index (BMI), we often find that our joints don’t safely allow our bodies to exercise without pain or risk to our ligaments and joints.

  • It’s at this point people begin to consider their options (medical intervention).
  • We find a holistic approach works best. Although part of the solution might be researching gastric bypass, gastric sleeve or other weight loss surgery procedures.

Some People Cannot Lose Enough Weight without Bariatric Surgical Intervention

  • Some people really struggle to lose weight
  • It can be especially difficult to change your BMI after becoming severely overweight, to the point of being classified as obese or morbidly obese. This means having a BMI of over 29.9 or 30.
  • Being obese makes it difficult to exercise. You also tend to feel lethargic or have sore joints (knees, hips, shoulders and elbows)

Despite exercising and eating as healthily as they can – no amount of dieting seems to help some individuals lose weight.

In these cases, they may need Bariatric Surgery or Gastric Sleeve Weight Loss Surgery.

gastric sleeve surgeon overweight BMI obese melbourne
  • There are multiple reasons why weight management is difficult.
  • Reasons can include; metabolic or hormonal changes, thyroid problems and even brain chemistry that fails to register ‘fullness’ after eating.
  • Bariatric Gastric Surgery – and making nutritional and dietary changes before and after weight loss surgery –  may be the best option for some individuals who’ve been unable to reduce obesity levels by any other measures.

Before we overview the Pre-Surgery and Post-Weight Loss Surgery diets, let’s talk about how nutritional choices and body weight interact.

Genetics, brain chemistry and lifestyle choices are all often intertwined in the occurrence of obesity.

  • People who are obese have likely gotten to the point that their stomach has the capacity and the emotional drivers to consume far more calories than they could ever hope to burn off. No matter how much they exercise.
  • It’s part genetics and sometimes related to medication side effects or an inability to exercise.
  • But research does show that obesity primarily relates to dietary intake; and that living a healthier lifestyle can go a long way to reducing excess body fat.

We all know that living with obesity is dangerous to health and longevity.

  • Too often, people resort to the latest fad diet or crash diet when they get fed up with being overweight.
  • This can help, temporarily, but is often non-sustainable in the longer term.
  • That’s because we recognise that imbalanced eating regimes and crash diets can have highly adverse impacts on our health.

Are fad diets dangerous?

These extreme diets can be very taxing to your organs and other body systems.

  • Extreme diet regimes are also unlikely to help keep the weight off over time.
  • In fact, diets often lead to further weight gain. This occurs once you go back to eating normally/as you did before.

Weight, Waistline & BMI factor into Obesity Health Problems

In such a scenario where your weight, your waistline and your BMI are at dangerously high levels in relation to your overall health – your GP may recommend a weight loss surgery such as; a Gastric Sleeve, Gastric Band Surgery, Gastric Bypass or a Lap-Band surgery procedure.

What is Gastric Sleeve Surgery?

Gastric sleeve diet - vector illustration of vertical sleeve gastrectomy vsg
  • A gastric sleeve surgery involves reducing the size of the stomach. This in turn helps patients lose weight by limiting how much food they can comfortably or safely consume.
  • Once the size of the stomach is reduced, a person’s appetite is also impacted. Meaning they feel hungry less often.
  • A person with a reduced stomach size also has the sensation of becoming fuller faster. This also helps to reduce food intake and excessive calorie consumption.

Gastric Sleeve Surgery is gaining more popularity since it has a much shorter operating time than gastric bypass or lap-band surgery but is effective at helping people lose weight to overcome obesity.

gastric sleeve and illustration of gastroplasty bariatric operative procedures, gastric banding gastric bypass operations, roux-en-y and biliopancreatic diversion

Unlike the lap band, Gastric Sleeves do not require adjustments.

Plus, it appears that surgery patients are able to lose more weight with a Gastric Sleeve procedure compared to a Lap Band or a Gastric Bypass.

Gastric Sleeve Diet Before Your Surgery (Liver Health)

  • If you choose to have this Gastric Sleeve surgery, your Specialist Bariatric Surgeon (Obesity Surgery Specialist) will give you specific pre-surgery and post-op diet details.
  • They’ll also advise you of the potential complications and surgical risks of gastric surgery.

If you’re very overweight or obese, you suffer from Non-Alcoholic Fatty Liver Disease.

gastric surgery gastric band
  • In general, several weeks prior to your surgery (at least 4 weeks before your surgery date), you’ll likely undertake a special diet to help shrink the size of your liver.
  • An enlarged or ‘fatty’ liver can impact your Surgeon’s access during your Bariatric operation.
  • A fatty liver also increases the risk of having serious complications from surgery, so you’ll need to be diligent in following your pre-op nutrition instructions and the prescribed liver-reducing diet (click here for an example).

Eating differently BEFORE your Gastric Sleeve Surgery not only helps to leave you healthier, but it also helps you prepare for an altered diet that you will need to adhere to AFTER your gastric surgical procedure.

What will be included in the pre-surgery eating plan

  • Your pre-surgery eating plan will likely include consuming a bit more protein and fewer carbohydrates than your normal eating regime.
  • You may also need to eliminate added sugars and avoid soft drinks. This can also help you lose weight as soft drinks are a contributing factor to rising sugar intake and higher obesity rates).
  • You must also drink lots of fluids or liquids to stay well hydrated (water is typically best)
    • Be careful that your higher liquid intake doesn’t include hidden sugars.
  • Your Gastric Sleeve Surgeon may also advise you to undergo a strictly liquid diet two days prior to the surgical day.
    • Your Bariatric Surgeon and Care Team will likely give you specific instructions for the months, weeks and days before your surgery.
    • Preparations and planning for bariatric surgery can take more time than you realise
    • So if you’re considering this option, be sure to book a consultation with your chosen Bariatric Surgeon as soon as you know you’re wanting the surgery to best prepare yourself for a Gastric Sleeve.

Nutritional Changes after Gastric Sleeve Surgery

In the days, months and years following your gastric sleeve surgery, you’ll need to take utmost care of your nutritional intake and eating routines.

Week One after Gastric Sleeve – What Might Be Typical (but ASK your Surgeon as this may not apply to you).

The information below is of a general nature and is not intended as advice.  It is also NOT a substitute for the medical information and pre and post-op recommendations provided to you by your GP and your Gastric Surgeon or other health professionals assisting you with your medical care. It is intended only as an information starting point for discussions with your Surgeon about how you’ll need to adapt your eating plan after Surgery.  Every patient, every procedure and every Bariatric Surgeon and Nutritional Team has a unique approach – so follow your Specialist’s instructions. 

In general, here is the general eating advice patients about to have Gastric Sleeve operations receive. However, YOUR post-weight loss diet instructions could VARY.

So ask your Doctor or Surgeon for specific post-op care to suit your specific health needs.

Week One after Weight Loss Surgery: What You Might Be able to Consume After Gastric Sleeve Surgery during the First Week After Having Surgery

Week 1: Clear Liquids Only

allowable clear fluids on gastric sleeve diet
  • In the first week after your gastric sleeve surgery, you may ONLY be able to drink clear liquids such as; water, fresh juices, soups and broths.
    • Typically, you’ll also need to take small sips to take in these liquids very slowly.
  • Decaffeinated tea and coffee are usually okay a few days after your Surgery
    • However, you’ll need to check this with your Surgeon
    • They might NOT be permitted for you in relation to your health or a specific procedure.
  • You should, however, avoid ALL carbonated beverages and drinks with added sugars.
  • If you’re readily able to tolerate liquids, then your Surgeon will advise you when you can advance to the next stage of eating changes.

Week Two After Gastric Sleeve Surgery: Pureed Foods


  • During the second week, you may typically take in foods in their pureed form.
  • These may include mashed potatoes, low-fat cottage cheese, sugar-free yoghurt, soup with blenderised vegetables and hot watery oatmeal.
  • You might be tempted to overdo it – but don’t. It’s not worth the risk and can get very uncomfortable very quickly if you eat the wrong foods, or too much of the right ones, after surgery.

Week Three After Gastric Sleeve Surgery: Protein Shakes and Soft Foods

  • In the third week, you might be able to take protein shakes about once a day, but ask your Surgeon to be certain.
  • You might also be approved to eat; hummus, steamed or boiled vegetables, soft cereals, scrambled eggs, mashed fruits, steamed fish, ground chicken with stock and soups.

Foods to avoid just after having Weight Loss Surgery:

  • You’ll need to avoid starchy foods like; rice, pasta and bread.
  • You should also avoid fibrous vegetables like broccoli, celery and asparagus as they are difficult to digest.

Week Four After Gastric Sleeve Surgery: Some Solid Meals

gastric sleeve diet soft foods what can i eat after gastric sleeve surgery

People ask when they will be able to eat solid foods or real meals after having weight loss surgery. The amounts will be forever changed, as you won’t be able to consume the portion sizes you once did. But in the 4th week after weight loss surgery or a gastric sleeve, you will be able to start eating some small portions of the following solid foods.

In the fourth week, your eating regime may be permitted to include some ‘solid’ meals.

  • You can typically start eating some fruits, sweet potatoes, baked potatoes, cereals, fish and chicken four weeks after having weight loss surgery.
  • Avoid eating fried foods, desserts, lollies, whole milk and nuts as these are very difficult to digest.
  • During the next week (Week 5), you can typically have one or two healthy snacks in-between your mealtimes.
  • A hard-boiled egg, a banana or hummus with soft rice crackers might be good options, but be sure you check with your Surgeon and Nutritionist.
  • The most important thing that needs to be kept in mind is that your meals should have high nutritional value (e.g., be nutrient-dense) as well as remain sparse in calories.

In the subsequent weeks and months AFTER your weight loss surgery, you’ll also have specific eating recommendations from your Surgical team, and you’ll need to monitor your eating regime and portion control.

How Long Before I see Weight Reduction after Gastric Sleeve Surgery?

weight loss concept blue male

It is often noted that patients can start seeing weight change results just weeks after their gastric surgery procedures. On average, with Bariatric Surgery, you can anticipate losing around 60% of your pre-surgery weight.

What about my skin after Gastric Band or Gastric Sleeve procedures?

gastric band, gastric sleeve, excess skin afterwards

Will I end up with skin folds and skin infections after having weight loss surgery?

Some patients get skin folds, others do not. It is quite common and some Australian Bariatric Surgeons don’t discuss this with patients in enough detail; so patients are dismayed by their body shape after losing weight – mostly relating to excess folds of skin.

Sadly, you can’t exercise away skin folds after losing weight.

Gastric sleeve surgery diet and nutrition

And excess skin, along with stubborn fat stores even after significant weight loss, means you’ll end up needing more surgery to get the body contours you are wanting after working so hard to get a healthier, more natural body shape after obesity.

If you need your redundant skin reduced to return smoother body contours, our leading Plastic Surgeon Dr Patrick Briggs (Post Massive Weight Loss Body Contouring Surgeons) offer many various Body Contouring procedures. The most common cosmetic surgeries or plastic surgeries after significant weight loss occurs include:

There is a sequence that you might want to ask your Surgeon about, and many people do Upper Body Lift procedures and Lower Body Lift procedures in stages. You might want to start with the surgery to reduce redundant skin in the area that troubles you the most. For Example; a thigh reduction or belt lipectomy or upper arm reduction surgery which is known as a Brachioplasty.

If after you have adopted your new healthy lifestyle and done everything you can to see changes in your weight, and are still not completely happy with the outcome after approximately 18 months to up to 4 years, you might also want to consider Liposuction and Body Contouring with one of our Specialist Plastic Surgeons.

Body Lift Surgeon Melbourne

Dr Patrick Briggs Melbourne

Melbourne Plastic Surgeon, Dr Patrick Briggs FRCS, FRCSI, FRCSI (Plast. Surg) is our Group’s top body contouring specialist for post-bariatric surgery patients. Dr Briggs and his colleagues are Specialist Plastic Surgeons who focus on patients who have lost massive amounts of weight either using bariatric surgery methods such as Gastric Sleeve Surgery or Gastric Banding.

They help individuals who have lost weight on their own through major lifestyle changes (but not everyone has success overcoming obesity without surgery), including offering Face Lifts, Tummy Tuck/Abdominoplasty procedures, Breast Lifts, Breast Reductions and Arm Reductions/Thigh Reductions as well as Belt Lipectomy (Circumferential Abdominoplasty) procedures.

For more information on Bariatric Surgery and Surgeons in Australia who can perform Gastric Sleeve or related Bariatric procedures, visit or send us an enquiry form below.

We can help you begin your journey to a whole new, holistic approach to reshaping your body after lifestyle changes and significant weight loss.

Read about one patient’s second Tummy Tuck surgery story after releasing 80 kilos through changing her lifestyle and eating routines.

For more information, send an enquiry below or give us a call during Clinic Hours on (03) 8849 1444

Further Reading about Body Surgery

Last updated: 24/10/2023
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Dr Patrick Briggs
Dr Patrick Briggs is an experienced Specialist Plastic Surgeon Now based in Melbourne, Australia. He is an expert in Breast, Body and Blepharoplasty Surgery with a special interest in Gender Surgery - Top Surgery. Dr Briggs has been published widely in surgical literature; he is trained and experienced in all aspects of Plastic and Cosmetic Surgery. Dr Briggs’ extensive experience across multiple surgical fields has allowed him to refine his skills to produce optimum results for his patients. Combined with his experience, Dr Briggs continually attends conferences and seminars to extend his knowledge and training surrounding the latest and best surgical techniques and equipment. By doing so he is able to provide his patients with the highest level of care and skill ensuring quality results.

Specialist Plastic Surgeons and ENT (Ear, Nose and Throat) Surgeon

With a wealth of experience and training, our Specialist Plastic and ENT (Ear, Nose and Throat) Surgeons are dedicated to best-practice patient care and education, customising Surgery for each and every patient to best meet their needs and desired surgical outcomes.

What to do next?

Our Patient Liaison Team can assist with any questions you may have when considering a procedure. You can send in an enquiry form below or call our Melbourne Clinic between 9 am – 5 pm Monday to Friday.

Phone 1300 599 990, Email us: or Book a FREE 15-minute Phone Chat with our Patient Liaison Manager or a Consultation with a Surgeon.

Disclaimer: Results depend on individual patient circumstances and can vary significantly. Results may also be impacted by a variety of factors including your lifestyle, weight, nutritional intake and overall health. Consult your Specialist Plastic Surgeon for details. This information is general in nature and is not intended to be medical advice nor does it constitute a doctor-patient relationship. Surgery risks and complications will be covered in detail during a consultation with your Surgeon.