The Best Guide To The Liquid Only Diet After Gastric Bypass Surgery

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While recovering from a gastric bypass, it’s important to follow the guidelines of your specific hospital or doctor. The rules will be different in most places and every place has their own timeframes for what should and shouldn’t be eaten after surgery! However, the one thing all patients must do after bariatric surgery is following a liquid only diet at the start. Today I’ll be discussing the liquid diet and offer suggestions as to the best liquids you can have.

liquid only diet

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Full Liquid Diet – Stage One After Gastric Bypass Surgery

After Bariatric Surgery you will need to follow a full liquid diet for the first 5 days. Smooth drinks are best and you can have either clear liquid or full liquid options. Some people may suggest drinking through a straw on the liquid diet, however most hospitals say to avoid this as putting gas into the stomach is not good after major surgery because there’s already excess air in there.

What Is A Clear Liquid Diet?

A clear liquid diet is a diet that consists of liquids that are easily digested and leave no residue in the intestines. A variety of clear liquids can be consumed, such as water, broth, sports drinks, juice, iced tea and coffee, without cream or milk, sodas, and seltzers.

Getting Nutrition From Liquids

A good way to make sure you drink enough is by taking small sips and making it a point not to gulp down your drinks. It’s best if at least 1-1.5 litres of this comes from nutritious liquids every day, which will ensure that you’re staying hydrated but won’t cause any stomach stretching or discomfort later on in the process. The liquid only diet is a good way to get nutrition especially when it’s the only nutrition you consume.

Best Liquids To Drink After Bariatric Surgery

It’s important you drink liquids during the first five days that have good amounts of nutrition. The best options are full liquids that are packed with nutrition. Protein shakes may be a good choice, however, ensure they do not contain sugar!

Here’s some examples of the best liquids to drink after bariatric surgery on the liquid only diet:

  • Sugar Free Protein shake – Ensure it contains at least 15 grams of protein per serving.
  • Skimmed or semi-skimmed milk fortified with skimmed milk powder (1-2 tablespoons per 200ml).
  • Slimfast powder added to skimmed milk. (1 serving Slimfast powder with 200ml skimmed milk).
  • Soup made from chicken stock, light consomme, bouillion or plain water (1 cup per serving).
  • Unsweetened fruit juices. These should be diluted 1:3 with water to lower the calorie content. Stick to just one glass per day.
  • Complan or similar high calorie drinks (1-2 cups per serving).
  • Tea and coffee (no milk or sugar, but you can add skimmed milk if you like).
  • Water–obviously, water is the best thing you can drink on a liquid diet. It’s hydrating and contains no calories or sugar. You should aim to drink at least 1-1.5 litres per day.

Best Liquids To Avoid After Gastric Bypass Surgery

There are some beverages that people may think is okay to drink after bariatric surgery which really aren’t.

To avoid gas buildup, bariatric patients need to stay away from fizzy drinks as they can have negative effects when consumed after gastric bypass surgery. In fact, you should never drink carbonated beverages again as it could cause severe pain to your stomach.

Similarly, alcoholic beverages are best avoided after weight loss surgery. It’s also not a good idea to drink too many fluids at once as this can also cause stomach discomfort. Finally, caffeinated beverages should be limited as much as possible as it can interfere with sleep and contribute to gastric problems.

Be sure to make sure you avoid bad liquids when on a liquid only diet.


Here is an example meal plan following Gastric Bypass Surgery:


Fruit smoothie (200ml)

Mid morning:

Fruit juice (200ml)


Complan or Nestle Build-Up milkshake including 2 tbsp skimmed milk powder or a glass semi-skimmed milk including 2 tbsp of skimmed milk powder.

Mid afternoon:

Slimfast shake


Thin soup with 1 -2 tablespoons of cows’ Milk included

Supper: Nestle Build Up Shake Plus water, tea, coffee sugar free squash in between meals.

When you feel ready, move on to Stage Two you can begin a puree stage diet. Some people move to this diet sooner than others and it depends on the individual.

What Can I Eat On After The Full Liquid Diet Stage?

Full Liquid only Diet – Stage Two

After stage one of the liquid diet you are allowed to have both chewable and liquid foods. It’s best to go slowly here though, start with protein shakes if you’re not used to having them before bariatric surgery, then advance onto soups with soft meats, blended veggies or fruit in it.

Full Liquid Diet – Stage Three

Stage three after bariatric surgery is where you can get into your regular bariatric meal plan. The bariatric meal plan is what you will follow for the rest of your life to avoid gaining weight again. You can find a great collection of bariatric meals and recipes over at The Inspiration Edit.

The Importance Of Keeping Hydrated After Surgery

One of the most important parts of bariatric surgery is to ensure you stay hydrated after gastric bypass.

Not only will this help with weight loss, but also helps to avoid uncomfortable side effects like constipation and abdominal bloating.

To stay hydrated make sure drink lots of water during bariatric surgery recovery, especially in between bariatric liquid only meals.

How To Help Reduce Gas Pain After Gastric Bypass Surgery

Following your surgery, you may suffer from gas pain. This is completely normal and you can treat it by using over the counter gas relief medication like Gas-X. However, if you’re not able to swallow or struggling another option you may want to try is peppermint tea.

Peppermint tea is a natural anti-inflammatory and can help relieve gas pain. You can also try drinking lemon or ginger tea as this will help reduce inflammation in your digestive system helping to speed up bariatric surgery recovery time!

In most cases you want to consume at least five bariatric full liquids a day which include water, coffee or tea with no added sugar, milk, bariatric milkshake or bariatric soup.

Best Guide To The Liquid Only Diet After Gastric Bypass Surgery

Drinking Soups After Gastric Bypass

We have over 50 soup recipes here on The Instant Pot Table many which are bariatric friendly. Here are three soups you may want to prepare in advance prior to your gastric bypass operation:

You should always check with your bariatric surgeon first before preparing bariatric soups and bariatric smoothies as bariatric surgeons may prefer you to stick with their bariatric diet guidelines.

Remember that you need to maintain a healthy bariatric diet to be successful after bariatric surgery.

If you’re looking for guidance on how to make bariatric smoothies, bariatric soups or bariatric protein shakes check out our recipes! You may just find one you love.

About Angela Milnes

Angela Milnes is a Qualified Early Years Teacher who has specialised in teaching. She has a wealth of experience teaching young children and adults. Angela has also taught cooking classes and loves to share both family recipes and easy instant pot recipes here on The Instant Pot Table. Follow her on Pinterest!

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