You had gastric bypass surgery. This surgery made your stomach smaller by closing off most of your stomach with staples. It changed the way your body handles the food you eat. You will eat less food, and your body may not absorb all the calories from the food you eat.

Your health care provider will teach you about foods you can eat and foods you should avoid. It is very important to follow these diet guidelines.

You will eat only liquid or puréed food for 2 or 3 weeks after the surgery. You will slowly add in soft foods, then regular food.

• When you start eating solid foods again, you will feel full very quickly at first. Just a few bites of solid food will fill you up. This is because your new stomach pouch holds only a tablespoonful of food at first, about the size of a walnut.
• Your pouch will get slightly larger over time. You do not want to stretch it out, so do not eat more than your provider recommends. When your pouch is larger, it will not hold more than about 1 cup of chewed food. 

You will lose weight quickly over the first 3 to 6 months. During this time, you may:

• Have body aches
• Feel tired and cold
• Have dry skin
• Have mood changes
• Have hair loss or thinning hair

These symptoms are normal. They should go away as you take in more protein and calories as your body gets used to your weight loss.

Remember to eat slowly and chew each bite very slowly and completely. Do not swallow food until it is smooth. The opening between your new stomach pouch and your intestines is very small. Food that is not chewed well can block this opening.

• Take at least 20 to 30 minutes to eat a meal. If you vomit or have pain under your breastbone during or after eating, you may be eating too fast.
• Eat 6 small meals throughout the day instead of 3 big meals. Do not snack between meals.
• Stop eating when you feel satisfied, but not too full. Eating just a little too much food will make you feel uncomfortable.
• Do not eat if you are not hungry.
• Use small plates and utensils to help control portion sizes.

Some foods you eat may cause some pain or discomfort if you do not chew them completely. Some of these are pasta, rice, bread, raw vegetables, and meats, especially steak. It may be better to stay away from these types of foods, and you should get advice from your provider about this. Adding a low-fat sauce, broth, or gravy can make them easier to digest. Other foods that may cause discomfort are dry foods, such as popcorn and nuts, or fibrous foods, such as celery and corn.

You will need to drink up to 8 cups (2 liters) of water or other calorie-free liquids every day. Follow these guidelines for drinking:

• Do not drink anything for 30 minutes after you eat food. Also, do not drink anything while you are eating. The liquid will fill you up. This may keep you from eating enough healthy food. It can also lubricate food and make it easy for you to eat more than you should.
• Take small sips when you are drinking. Do not gulp.
• Ask your provider before using a straw, since it may bring air in your stomach.

You will need to make sure you are getting enough protein, vitamins, and minerals while you are losing weight quickly. Eating mostly protein, fruits, vegetables, and whole grains will help your body get the nutrients it needs.

Protein may be the most important of these foods early after surgery. Your body needs protein to build muscles and other body tissues, and to heal well after surgery. Low-fat protein choices include:

• Skinless chicken.
• Lean beef (chopped meat is tolerated well) or pork.
• Fish.
• Whole eggs or egg whites.
• Beans.
• Dairy products, which includes low-fat or nonfat hard cheeses, cottage cheese, milk, and yogurt.

Combining foods with texture together with protein helps people who have had gastric bypass surgery band stay satisfied longer. This includes things like a salad with grilled chicken or toast with low fat cottage cheese.

After gastric bypass surgery, your body may not absorb enough important vitamins and minerals. You will need to take these vitamins and minerals for the rest of your life:

• Multivitamin with iron.
• Vitamin B12.
• Calcium (1200 mg per day) and vitamin D. Your body can absorb only about 500 mg of calcium at a time. Divide your calcium into 2 or 3 doses during the day. Calcium must be taken in the "citrate" form.

You may need to take other supplements also.

You will need to have regular checkups with your provider to keep track of your weight and to make sure you are eating well. These visits are a good time to talk with your provider about any problems you are having with your diet, or about other issues related to your surgery and recovery.

Avoid foods that are high in calories. It is important to get all of the nutrition you need without eating too many calories.

• Do not eat foods that have a lot of fats, sugar, or carbohydrates.
• Do not drink much alcohol. Alcohol has a lot of calories, but it does not provide nutrition. You can absorb alcohol much more quickly after gastric bypass, and you won’t be able to tolerate as much as you did before surgery.
• Do not drink fluids that have a lot of calories. Avoid drinks that have sugar, fructose, or corn syrup in them.
• Avoid carbonated drinks (drinks with bubbles), or let them go flat before drinking.

Portions and serving sizes still count. Your dietitian or nutritionist can give you suggested serving sizes of the foods in your diet.

If you gain weight after gastric bypass surgery, ask yourself:

• Am I eating too many high-calorie foods or drinks?
• Am I getting enough protein?
• Am I eating too often?
• Am I exercising enough?

Contact your provider if:

• You are gaining weight or you stop losing weight.
• You are vomiting after eating.
• You have diarrhea most days.
• You feel tired all the time.
• You have dizziness or are sweating.

Gastric bypass surgery - your diet; Obesity - diet after bypass; Weight loss - diet after bypass

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Updated by: John E. Meilahn, MD, Bariatric Surgery, Chestnut Hill Surgical Associates, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.