General Dietary Guidelines for Gastric Bypass and Gastric Band Patients

What you eat, how you eat, and how much you eat changes after bariatric surgery. Keep in mind that your surgery will help determine the amount of food you can consume, but you determine the quality of the food.

Below is a general listing of dietary guidelines and phases for pre- and post-operative weight loss surgery patients. These may change, depending on your personal circumstances. It is important that you follow the slow progression from liquids to solids and that you do not advance the foods until Dr. Provost or his team members tell you to move to the next phase. The purpose of the post-op diet progression is to help in the healing process, minimize stress on surgical sites, and allow time for your body to adapt to the new eating patterns. You may cause yourself unnecessary complications if you do not follow these guidelines.

Pre-op Diet

For two weeks prior to surgery: you will be on a special low-calorie/ low-carbohydrate liquid diet. It is very important that you follow this diet, as its purpose is to shrink the size of your liver before surgery. This decreases your chances of having complications or needing an open operation.

Night before and morning of surgery: you should have nothing to eat or drink after midnight.

  • 1-2 days after surgery: you will be on clear liquids, such as water, Crystal Light, broth, and sugar free juices. You will be sent home on full liquids.
  • 1 – 2 weeks after surgery (PHASE I “Full Liquids”): you will be on full liquids, such as protein drinks, broths, and decaffeinated / sugar free / non-carbonated beverages.
  • 2 – 5 weeks after surgery (PHASE II “Softs”): You will still be on liquids, such as protein drinks, but will add soft / pureed items, like tuna, eggs, chicken, vegetables, and fruit. Soft and pureed foods are foods with a consistency of a smooth paste or a thick liquid or are ground or finely diced. Continue lots of sugar free / calorie free / non-carbonated beverages.
  • 3 – 5.5 weeks after surgery (PHASE III “Solids”): you will have an appointment with our dietician via phone or in person to advance you to solid foods, such as all meats, vegetables, fruits, and whole grains and lots of sugar free / calorie free / non-carbonated beverages. This will be your lifelong food plan and we do not want you to go back to phase I or II unless we direct you to do so.

During the diet progression, you eat several small meals a day and sip liquids slowly throughout the day (never with meals). You might first start with four to five small meals a day, then when following a regular diet, decrease to three meals a day. Each meal should include protein-rich foods, such as lean meat, fish, poultry, or eggs, that are eaten first.

Life-long Changes: New Eating Habits and Behaviors

Once you are at Phase III “solids”, to avoid problems that may require re-operation and to ensure you’re getting nutrients you need, you should closely follow the guidelines below. We encourage you to adopt these habits BEFORE surgery.

  • Eat solid protein at each meal. We want you to feel satisfied after a small amount of food and to stay satisfied for several hours. This will only be achieved if you eat protein at each meal. Acceptable solid protein choices include: beef, chicken, turkey, eggs, pork, fish or other seafood. We DO NOT encourage you eating mushy or crunchy low-protein foods, such as cheese, beans, yogurt, peanut butter, and nuts as your main protein with a meal.
  • Eat small amounts. Just after surgery, your stomach holds only about 1 ounce of food. Though your stomach stretches over time to hold more food, by the end of three months, you may be able to eat 1 to 1 1/2 cups of food with each meal. Eating too much food not only adds more calories than you need, but also may cause pain, nausea and vomiting. Make sure you eat only the recommended amounts and stop eating before you feel full. Remember, the goal is not to be stuffed, but to be satisfied on a small amount of food.
  • No more then 15-20 minutes at each meal. Once patients are used to their new eating pattern, we ask that they take no longer than 15-20 minutes at each meal. If you sit for a long period of time at meals, you will be able to eat more and you will stretch your new pouch. In essence, you will defeat the purpose of your surgery.
  • Avoid all carbonated beverages. This includes diet and non-diet sodas and beer.
  • Take pea-sized bites and chew food thoroughly. The new opening that leads from your stomach into your intestine is very small, and larger pieces of food can block the opening. Blockages could cause vomiting, nausea and abdominal pain. Take pea-sized bites of food and chew them 15-20 times before swallowing.
  • Drink NON-CALORIC liquids between meals. This means we DO NOT want you drinking juice, milk (even skim), sweet tea, Starbucks drinks, protein / vitamin water, or soups. Please avoid caloric beverages, as these will all lead to weight gain or little weight loss. You may have water, Crystal Light, coffee or tea (sweetened with no-calorie sweetener).
  • No drinking 30 minutes before, during, and up to 1 hour after meals. Drinking liquids with your meals can cause pain, nausea and vomiting, pouch dilation or dumping syndrome (in gastric bypass patients). Expect to drink at least 6 to 8 cups (48 to 64 ounces) of fluids a day to prevent dehydration.


Dr. Provost expects you to be up and in a chair the night of your surgery and walking the halls the day after your surgery. Once you go home, you should begin exercising immediately. Walking is the easiest exercise.  We expect that you will engage in DAILY sustained aerobic exercise, beginning at 5 minutes per day and working your way up to 30 minutes per day. This aerobic activity may include:

  • Swimming
  • Jogging
  • Walking
  • Biking
  • Seated chair exercises
  • Dancing
  • Aerobics or other fitness classes

You will know you are getting a good workout because you are sweating a little and feeling a little short of breath. Although housework, walking or climbing stairs at work, parking far away in parking lot, and playing with children are all great starts, but we would like you to advance to more vigorous, sustained exercise as your health improves.

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