Gastric Sleeve Post-Op Diet: What to Expect

Christie Auyeung General Health, General Surgery, Travel, Weight Loss, Weight Loss Surgery Leave a Comment

Gastric sleeve surgery is a life-changing procedure. After the surgery, patients are required to make many behavior, lifestyle, diet and exercise changes, and maintain healthy habits for the rest of their lives.

A big part of gastric sleeve surgery success is sticking to the right diet. Gastric sleeve surgery cuts the capacity of the stomach down from 60 ounces to around 3 ounces. With such a dramatic reduction in size, patients have to pay particular attention to what and how they eat in order to avoid discomfort and gaining the weight again.

So what’s a good post-gastric sleeve surgery diet to keep the body healthy? There are actually four phases of the gastric sleeve surgery diet. Let’s break down each phase and what to expect.

Phase 1: Clear Liquid Diet
  • This phase starts right after surgery, and usually lasts around 5-7 days.
  • A clear liquid diet gives the body a chance to heal and the stomach time to adjust to its new size and functionality.  
  • The goal of this phase is to keep the body hydrated. Thus, patients usually take in about two ounces of water every half hour to start. Then, the amount is increased to around six to eight ounces every hour.
  • Patients should drink water very slowly, in small sips, during this phase.
  • Sugary, caffeinated or carbonated beverages can cause complications, so it’s best to avoid them. Instead, opt for water, ice chips, flavored water, clear broths, or herbal teas.


Phase 2: Full Liquids Diet
  • This phase lasts about one week.
  • The goal of this phase is to keep the body hydrated, and also start taking in small amounts of protein. This gives the body a chance to continue healing, while also adjusting to more substantive foods.
  • Most surgeons give their patients vitamin supplements to take during this time as well.  
  • Most food at this point comes in the form of liquids or soft foods that don’t require chewing. That includes protein powders, low-sugar yogurt, almond milk, applesauce, vegetable juices, hot cereals, sugarless pudding, and soups.
  • Again, patients should avoid carbonated, sugary, or caffeinated beverages , and should drink at least 50 ounces of water each day to stay hydrated.


Phase 3: Soft Foods Diet
  • This phase lasts around one week.
  • The goal of this phase is to adjust to eating solid foods, primarily protein.
  • Patients should chew food down to applesauce consistency, otherwise may cause discomfort, vomiting, and stomach irritation.
  • Aim to eat no more than 6 ounces of food per meal – 3 ounces of protein, one ounce of healthy fat, and another two ounces for fruits, vegetables or carbs.
  • Good foods to start with include scrambled eggs, cottage cheese, tofu, mashed or canned fruit and bananas – just try adding one food at a time.
  • Stop drinking 30 minutes before and after a meal, otherwise all food will slip through the stomach like a funnel and cause discomfort.
  • Only eat until satisfied and no more.


Phase 4: Solid Foods Diet
  • This phase starts around 3 weeks after surgery and is permanent.
  • At this point, the stomach is better equipped to handle solid foods.
  • Aim for healthy, well-balanced, and small-portioned meals. Each meal should be between four to eight ounces, including at least 3 ounces of protein.
  • It may be easier to remember the 3:1 rule – each three bites of protein for one bite of everything else. It may also be helpful to use a digital pocket scale in the beginning
  • Food that is easiest to digest include fish, shrimp, eggs, chicken, tofu, beans, cottage cheese and Greek yogurt. It’s the hardest to digest red meat.
  • This will be the diet to stick to permanently

With an understanding of the four phases of the post-gastric sleeve surgery diet, patients can better set themselves up for success after their procedure. Surgeons can provide more details about each phase of the diet, as well more specific recommendations tailored to the patient.

Got more questions about gastric sleeve? Don’t hesitate to reach out one of our world-class doctors today!

Christie is a UChicago grad currently living in the San Francisco Bay Area. In her free time, she enjoys tap dancing, learning to windsurf, and trying new foods.