Post-op Diet Progression

The postoperative gastric bypass diet unfolds in several stages, from "liquids only" to small meals of pureed or soft, high-protein foods and finally regular consistency foods. Meals on the new menu will be much smaller than normal. Initially, the foods eaten must be very smooth in texture until you can tolerate soft chunks and finally regular consistency foods.

In all stages of the diet, it is especially important to drink enough water, and to take vitamin and mineral supplements as prescribed. You will progress through the stages spending approximately one week each on stage 1 and 2. Take five weeks to progress slowly through stage 3. You should expect to start eating regular foods at approximately six to eight weeks. Below is a summary of what to expect.

Stage 1

Week 1


The first stage of the gastric bypass diet, clear liquids (meaning beverages that you can almost see through), usually lasts for five to seven days after the operation.

The clear liquid diet starts with sips of water, and then allows foods like:

  • Sugar-free diluted juice
  • Diet gelatin
  • Bouillon or clear broth
  • Flat no fizz diet soda in small amounts
You should drink approximately 2 ounces every 15 minutes or 8 ounces in an hour.


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Stage 2

Week 2


If no problems are experienced with clear liquids, the gastric bypass diet advances to semi-liquids which include high-protein liquids like Sugar-Free Carnation Instant Breakfast or another high protein, low sugar drink, as well as other thick liquids with a consistency similar to cream of wheat.

This stage of the diet lasts for one week. Most patients also begin taking a chewable multivitamin/mineral supplement, chewable calcium, and iron at this stage. Fluids continue to be consumed at the same rate as in stage 1. It is imperative that you stay hydrated and prevent loss of muscle mass.


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Stage 3

Week 3 - 6


The physician will indicate when it is time to advance to smooth pureed foods. Some patients are able to start stage 3 after they have been out of the hospital for about two weeks. Others may need to wait longer. In this stage, you will progress from smooth pureed foods to soft, chunky foods over the course of three weeks.

The puree diet includes blenderized foods such as:

  • Cottage cheese
  • Casseroles
  • Lean meats like tuna fish, chicken or pork
  • Vegetables such as carrots or beets
Some patients find it more convenient to use strained baby foods. It is important to make sure that all foods are pureed or extremely soft and smooth in texture. You may progress to soft chopped or ground foods after approximately one to two weeks of smooth pureed foods. It is very important to chew all of your food well and eat slowly. Consume your high protein choices first. Continue to take a protein supplement between meals.


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Regular Diet

After Six to Eight Weeks


The regular diet starts about six to eight weeks after gastric bypass surgery. You may continue to add new foods one at a time with the goal of achieving a well balanced diet of about 1,000 calories per day.

While this diet includes all six food groups, it is important to fill up with high-protein foods, such as lean protein, protein alternatives and dairy products, at every meal. Each meal or snack should be small with liquids consumed in between meals. Ask a dietitian for advice on planning an individualized regular diet pattern.


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Follow-up


Shared medical appointments are held bimonthly. The meetings offer comfort and support for patients who have had weight loss surgery.

Patients who are interested in the surgery and would like advice, are encouraged to attend this meeting to gain insight regarding the postoperative diet and implications of the surgery.
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