Diet | Bariatrics | Surgery and Medicine in Iowa

Your New Stomach A New Way of Eating

Gastric Bypass Diet Progression: From The Day After Surgery to The Rest of Your Life


This gastric bypass diet will allow your new stomach to rest to that your staple line can heal properly. All liquids should be smooth and this with absolutely no chunks or pieces. You will need to take small sips of liquids continuously throughout the day in order to stay hydrated. For more information on the bariatric liquid diet, refer to the Nutrition Information section of your education day binder.


Pureed foods should be well blended to a milkshake, pudding, or baby food consistency. You will have several small (1/4 cup) pureed meals each day. It is important to take your time with meals and eat slowly. You will need to stop drinking your liquids 10 minutes prior to meals and wait at least 30 minutes after a meal to start drinking again. For more information on the bariatric pureed diet, refer to the Nutrition Information section of your education day binder.


Soft foods should include only cooked fruits and vegetables and tender cuts of meats. Chop all foods to the size of a pea before eating. You will still need to avoid fibrous foods, seeds, peels, and gummy starches (pasta and untoasted bread). You will need to continue avoiding drinking fluids with meals and wait at least 30 minutes after a meal to start drinking again. For more information on the bariatric soft diet, refer to the Nutrition Information section of your education day binder.

bariatric general diet: week 5 - lifetime after surgery

Even though you won't be able to eat as much food after surgery, making poor food choices and being inactive will make you less successful with your weight loss. Also, certain behaviors may promote weight regain, such as grazing or frequent snacking, drinking soda and other drinks loaded with calories, drinking any fluids with meals, or repeatedly eating large servings of food.

When you reach 1 year after surgery, most patients feel satisfied and are able to consume 3/4 to 1 cup food at meals. In order to stay successful, do not exceed this amount of food at meal times. To ensure you're getting enough protein while eating smaller meals, you will likely need additional protein snacks or supplements between meals. You will need to continue avoiding drinking fluids with meals and wait at least 30 minutes after a meal to start drinking again. For more information on the bariatric general diet, refer to the Nutrition Information section of your education day binder.

Protein Shakes and Drinks

Protein is an important nutrient for everyone, but it becomes even more important after weight-loss surgery when your calories are very low. Proteins have many jobs, including making body tissue, brain chemicals, hormones, and immune cells and helping numerous other processes take place. If you do not eat enough protein after surgery, you will not heal as well, your energy levels will be lower, you will lose more muscle and less fat, and you may lose more hair. Eat or drink a minimum of 60-80 grams of protein each day. The dietitian will give you a more specific protein goal during your hospital stay.

What to look for on the Nutrition Facts Panel when selecting a protein supplement:

  • Check the ingredients list. Look for a whey protein isolate, soy protein isolate, or calcium caseinate as the first ingredient. (Avoid collagen-based proteins!)
  • For an 8 ounce serving, your protein supplement should have:
    • 20-30 grams of protein,
    • Less than 200 calories,
    • Less than 5 grams of sugar,
    • Less than 3 grams of fat

Protein powders may be missed with water, a sugar-free beverage, skim or 1% milk, unsweetened soy milk, or unsweetened almond milk. After surgery, your protein supplement may taste different and become "too sweet". Keep this in mind when purchasing supplements ahead of time.

If you are lactose intolerant or having gastric bypass surgery, you will likely want to use a whey protein isolate or soy protein isolate supplement to avoid symptoms of lactose intolerance (i.e., cramping, gas, bloating and diarrhea).

For more information on ways to increase your protein intake, refer to the Nutrition Information section of your education day binder.

general information

Chew your food thoroughly. With the reduction in the size of your stomach and other changes in your anatomy, you must thoroughly chew your food before swallowing. Not chewing your food enough could result in pain, nausea and vomiting after surgery. Start with smaller bites and cut food into tiny pieces, like the size of a pea or pencil eraser. You could also try using smaller utensils, like a child's fork, to control bite size.

Eat slowly and stop eating when you feel full or comfortably satisfied. It is important to recognize your feeling of fullness and prevent getting sick. When you feel a pressure in your upper stomach area, this is your new full feeling. If you experience pain, you probably took one too many bites, or perhaps ate too quickly. Sit down during meals and focus on eating. Avoid activities (i.e. reading, watching TV, phone) while eating where you can become distracted.

Drink beverages slowly and only between meals. Drinking too quickly, gulping and/or drinking too soon after eating solid food may cause pain, discomfort or other intolerances. Avoid fluids 10 minutes prior to mealtime and during the meal. Then, wait 30 minutes after the meal is over before you resume drinking. Straws, especially large straws, may introduce air into your stomach (like gulping) and cause bloating and discomfort.

Drink adequate amounts of fluids to prevent dehydration. Fluid needs are individual and some people may require more fluid to maintain adequate hydration than others. Aim for at least 64 ounces (8 cups) per day unless you have been given a different amount by a physician or dietitian. Increase your fluid intake if you are having signs or symptoms of dehydration: decreased or dark urine, nausea, headache, dizziness, lack of energy, dry skin, dry mouth or a white coating on the tongue.

Avoid drinking beverages that contain carbonation, caffeine, sugar and alcohol. Carbonation may cause abdominal discomfort and may stretch out your new stomach over time. Caffeine may irritate the stomach and increase your risk for an ulcer after surgery. Caffeine, as well as alcohol, may also contribute to dehydration. Beverages containing sugar and alcohol are high in calories and will hinder your weight loss. They may also cause Dumping Syndrome. And last but not least, alcohol metabolism is changed after surgery and you may feel the effects of alcohol more quickly. If you choose to drink alcohol in moderation after surgery, please do not plan on driving.

Vitamins & supplements - bypass & sleeve

Before surgery, if you are not already taking a multivitamin, please start.

The changes to your digestive system caused by weight-loss surgery make it harder for your body to absorb certain nutrients. After weight-loss surgery, you are more likely to develop certain nutrient deficiencies and you will not be able to meet all of your nutritional needs with food alone - this will be the case even years after the surgery, and even after you are eating normal servings of a well-balanced diet.

Therefore, when you have weight-loss surgery, you need to take certain vitamin and mineral supplements for the rest of your life. You should be prepared to make this commitment when you decide to have weight-loss surgery.

At the minimum, you will likely need to purchase a multivitamin with iron and calcium citrate. Surgical Associates may also tell you to take additional vitamins such as Vitamin D or Vitamin B12. If you have a history of anemia or are a woman with a heavy menstrual cycle, you will need higher amounts of iron.

To improve absorption of nutrients and avoid any possible obstruction, Surgical Associates recommends multivitamins and calcium supplements be taken as chewable tablets for AT LEAST the first 2 months if not for a lifetime. If you later decide to switch to a pill form, soft gels or capsules may be better absorbed than tablets. If additional Vitamin B12 supplementation is needed, it should be taken as a chewable tablet, sublingual (under the tongue), or as a liquid for a lifetime to improve absorption.



Recommended Daily Amounts After Gastric Bypass or Sleeve Gastrectomy

Vitamin A

5,000-10,000 IU

Vitamin D

3,000 IU of Vitamin D3

Vitamin E

15 mg

Vitamin K

90-120 mcg

Vitamin B 1 (thiamin)

12-100 mg


(folic acid)

400-800 mcg

800-1,000 mcg for women of childbearing age

Vitamin B 12

350-500 mcg


1,200-1,500 mg  (see below for additional information)


18 mg for men and post-menopausal women

45-60 mg if you have anemia or a heavy menstrual cycle


8-11 mg (sleeve gastrectomy)

8-22 mg (gastric bypass)


1 mg (sleeve gastrectomy)

2 mg (gastric bypass)


  • There are different types of calcium:
    • Calcium Citrate: may be taken with or without meals. This version of calcium is believed to be better tolerated and absorbed after surgery. This type of calcium is preferred by Surgical Associates.
    • Calcium Carbonate: should be taken with meals to improve absorption and should not be taken if you have a history of kidney stones.
  • You must take at least two doses of calcium daily. Your body can only absorb 600 mg at a time, and you will require 1,200-1,500 mg per day after surgery. For this reason, separate each dose by at least 2 hours.
  • Keep in mind that vitamins containing Iron may not contain sufficient calcium to meet the recommended needs. Read the label carefully and purchase additional calcium as needed.
  • If possible, choose a calcium supplement with Vitamin D and Magnesium. All three nutrients work together for bone health.

Tips for Staying On Track

  • Avoid high calorie, sugared liquids- fruit juices, or pop. Avoid sugar by reading labels on products. DO NOT eat anything if the label indicates more than 10g of the following substances in the first three ingredients of the product: sugar, maple syrup, honey, molasses, corn syrup, corn sweeteners, glucose, lactose, maltose, dextrose, fructose, sorghum, sorbitol, or mannitol. You may use artificial sweeteners such as Equal and Splenda.
  • Each meal should take twenty to thirty minutes. Any time shorter than that means you ate too fast or not enough and will get hungry again. Taking more time means you are probably eating too much. Eating slowly helps you feel full much longer.
  • Liquids have to be taken before solids. Drink before a meal not during or close after the meal; you will wash your food down too quickly otherwise.
  • Only use solid food, like beef jerky, cheese, nuts, or veggies for snacking. If you eat small meals of junk foods, you will not lose weight.
  • Quit when you are full. Stop at the first sign of fullness. Learn to recognize your “quit eating” signals.
  • Eat from a salad plate instead of a dinner plate. The plate will be fuller with less food and provide psychological satisfaction that you are eating a full meal.


  • Small portions 4 to 6 times each day
  • Protein first
  • Do not drink and eat together
  • Drink 6-8 8oz. glasses of liquid each day
  • Drink protein supplements until your surgeon allows you to stop.
  • Take vitamins and calcium
  • Chew thoroughly
  • Eat slowly
  • Limit Sugar


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