About 23 years ago I had an RNY gastric bypass surgery. You can learn more about that, and my subsequent years of dieting, by reading ABOUT ME. This resulted in me eating an extremely low-calorie diet during the first 6 months after surgery, and a very-low-calorie diet during that following year. This type of eating caused me to lose 110 pounds during that time period.

The dieting industry makes billions of dollars every year by marketing its foods, supplements, and services. It encourages people to use MORE foods and other diet products, while people actually need to use far LESS. As a result, most people are unaware of how VERY LITTLE FOOD is required by a person wishing to lose weight - especially by a person who has an obese body with a great deal of stored fat which needs to be used as energy.

For the first few months following a gastric bypass surgery, a person’s calorie intake is between 300 and 600 calories per day. The recommended meal portion size is 1/4 cup for a solid meal and 1/2 cup for a liquid meal.

The volume of the plated meal in the picture at the top of the page is about 1/3 to 1/2 a cup which is MORE than 1/4 cup of food.  To reduce the amount food on that plate to 1/4 cup, visualize removing some of that little round potato. 

Immediately following surgery, the stomach size is very small - about 1/4 cup, or the size of an egg. The opening that allows food to pass out of one’s stomach is also very narrow. For this reason, it is important to take only two to three sips or bites at a time of any NEW food and then wait 10 minutes before taking more. This will help a person learn one’s limits and tolerance. Liquids will empty faster from the stomach than soft solids.

See Below for the standard Dietary Guidelines for after Bariatric Surgery, provided by the University of California San Francisco Medical Center:  

Dietary Guidelines After Bariatric Surgery

General Guidelines
• Eat balanced meals with small portions.
• Follow a diet low in calories, fats and sweets.
• Keep a daily record of your food portions and of your calorie and protein intake.
• Eat slowly and chew small bites of food thoroughly.
• Avoid rice, bread, raw vegetables and fresh fruits, as well as meats that are not easily chewed, such as pork and steak. Ground meats are usually better tolerated.
• Do not use straws, drink carbonated beverages or chew ice. They can introduce air into your pouch and cause discomfort.
• Avoid sugar, sugar-containing foods and beverages, concentrated sweets and fruit juices.
• For the first two months following surgery, your calorie intake should be between 300 and 600 calories a day, with a focus on thin and thicker liquids.
• Daily caloric intake should not exceed 1,000 calories.

Fluids
• Drink extra water and low-calorie or calorie-free fluids between meals to avoid dehydration. All liquids should be caffeine-free.
• Sip about 1 cup of fluid between each small meal, six to eight times a day.
• We recommend drinking at least 2 liters (64 ounces or 8 cups) of fluids a day. You will gradually be able to meet this target.
• We strongly warn against drinking any alcoholic beverages. After surgery, alcohol is absorbed into your system much more quickly than before, making its sedative and mood-altering effects more difficult to predict and control.

Protein
Preserve muscle tissue by eating foods rich in protein. High-protein foods include eggs, meats, fish, seafood, tuna, poultry, soy milk, tofu, cottage cheese, yogurt and other milk products. Your goal should be a minimum of 65 to 75 grams of protein a day. Don't worry if you can't reach this goal in the first few months after surgery.

Supplements
You must take the following supplements on a daily basis to prevent nutrient deficiencies. Please remember that all pills must be crushed or cut into six to eight small pieces. You are not able to absorb whole pills as well as before surgery, and it can be difficult for the pills to pass through your new anatomy.

Multivitamins
Take a high-potency daily chewable multivitamin and mineral supplement that contains a minimum of 18 mg of iron, 400 mcg of folic acid, selenium, copper and zinc. Brands that contain this formula include Trader Joe’s and Centrum Adult chewable multivitamins. Take two tablets daily for at least three months after your surgery, and then one tablet daily for life.

Calcium Supplement
Take 1,200 to 2,000 mg of calcium daily to prevent calcium deficiency and bone disease. To enhance absorption, take the calcium in two to three divided doses throughout the day - for example, a 500 to 600 mg supplement taken three times a day. Calcium citrate is the preferred form of calcium.

Vitamin D Supplement
Take a total of 800 to 1,000 International Units (IUs) of vitamin D each day. This total amount should be taken in divided doses of 400 to 500 IUs twice a day. Vitamin D should be taken with your calcium supplement. If you prefer, you can take a combination calcium-vitamin D supplement to avoid taking multiple pills, so long as it contains the proper dosages.

Vitamin B12 Supplement
Take 500 mcg of vitamin B daily. It can be taken as a tablet, or in sublingual forms placed under the tongue.

Other Supplements
Some patients need additional folic acid or iron supplements, particularly women who are still menstruating. Your dietitian will discuss this with you.

Diet Progression After Bariatric Surgery

Immediately following surgery, you will begin with a clear liquid diet. You may gradually start adding thicker liquids to your diet after you are discharged from the hospital.

Two weeks following surgery, you may progress to blended and pureed foods. You may use high-protein (more than 20 grams protein), low-calorie (less than 200 calories) liquid supplement drinks or powders to meet your protein requirements during this period.

It is important to know that following surgery, your stomach size is very small - less than 1/4 cup, or about the size of an egg. The opening that allows food to pass out of your stomach is also very narrow. For this reason, it is important to take only two to three sips or bites at a time of any new food and then wait 10 minutes before taking more. This will help you learn your limits and tolerance. Liquids will empty faster from your stomach than soft solids.

If you overeat or eat too quickly, you may experience nausea or pain. You should avoid rich, creamy liquids such as gravies, sauces and ice creams.

Diet in the Hospital

You will receive clear liquids such as juices, Jell-O and broth as your first meal following surgery. Juice and Jell-O are high in sugar content, but your portions will be very small at this stage. Gradually increase the amount you drink at each meal as you can tolerate it.

Diet for the First Two Weeks Post-Surgery

You will begin adding thicker liquids that are high in protein and low in fat and sugar. (For examples, see the list below.) You may use high-protein, low-calorie liquid supplement drinks or powders to meet your protein requirements during this period.
The goal is to consume small portions that will empty easily from your pouch. Begin with 1 tablespoon portion sizes and increase to 2 tablespoons as tolerated. Begin drinking 1/4 cup of liquid at a time and increase to a 1/2 cup as tolerated. Your daily caloric intake should not exceed 400 calories.

It is also very important to stay well hydrated. Drink 1 to 1.5 liters of water or other non-caloric liquids per day.
Recommended thicker liquids:

• Nonfat or 1% milk, if you can tolerate milk
• Lactose-free or soy-based low-calorie drinks
• Sugar-free pudding
• Sugar-free, nonfat yogurt
• Low-fat cottage cheese
• Blended broth-based soup or other low-fat soups
• Refined hot cereals that are low in fiber, such as cream of rice or cream of wheat. Make them with extra liquid to create a soup-like consistency. Do not eat oatmeal.
• Optional high-protein, low-calorie liquid supplement drinks (drinks containing less than 200 calories and more than 20 grams of protein in an 8- to 11-ounce serving).

To increase your protein intake, add 2 tablespoons non-fat dry milk powder, egg substitute or powered egg, or other protein powder to each 1/2 cup of nonfat or low-fat milk. You can also add these to soups, hot cereal and other thick liquids.
Remember to drink 1 cup of water or other non-caloric fluids between meals. Take a multivitamin supplement every day.

Diet for Weeks Two to Four Post-Surgery

Begin adding very small portions of pureed and soft foods as tolerated. Take very small bites and chew everything very well. Do not take more than two bites every 20 minutes when adding a new food.
Recommended pureed and soft foods:

• Applesauce
• Yogurt
• Cottage cheese
• Well-cooked, pureed vegetables
• Hot cereals
• Mashed potatoes
• Noodles
• Scrambled egg whites or egg substitute
• Canned fruits
• Canned tuna fish
• Lean fish
• Tofu
• Lean ground meats or poultry

Avoid all bread and meats that are not easily chewed.

Recommended Meal Plan For Weeks Two to Eight Until Two Months Post-Surgery

At this time, your caloric intake will probably be no more than 500 calories a day, divided into six to eight small meals.
Recommended portion sizes are 1/4 cup for solids and 1/2 cup for liquids.

Sample Menu
This sample menu includes different foods that are safe for you to eat. You may adjust the menu to fit your tastes and tolerance.

Breakfast
1/4 cup hot cereal made with non-fat milk
Mid-Morning
1/2 cup nonfat milk*
Late Morning
Two scrambled egg whites
Lunch
1/2 cup low-fat chicken noodle soup
Mid-Afternoon
1/4 cup low-fat cottage cheese
Late Afternoon
1/4 cup sugar-free, nonfat yogurt
Dinner
2 ounces lean ground meat
1/4 cup pureed or well-cooked vegetables
Bedtime Snack
1/4 cup non-fat milk
* Add 1 tablespoon non-fat dry milk powder to each 1/4 cup nonfat milk for additional protein.

Remember to drink 1 cup of water or other non-caloric fluids between meals. It is important to take a multivitamin and mineral supplement every day, plus additional iron if required, and calcium and vitamin D supplements two to three times per day.

Recommended Meal Plan for Two to Six Months Post-Surgery
Consume 900 to 1,000 calories and at least 65 to 75 grams of protein a day. For balanced nutrient intake, your daily servings should include:

• 3 servings milk and dairy products (nonfat and low-fat)
• 3 servings meat or meat alternative (lean and low-fat)
• 3 servings starch (limit bread and rice)
• 1 serving fruit (avoid dried fruits and fruits with skin)
• 2 servings vegetable (well-cooked only)

Recommended portion sizes are 1/4 cup for solids and 1/2 cup for liquids.

Discontinue taking high-protein liquid supplement drinks or powders if possible. We recommend meeting your protein needs with food.

Sample Menu
This sample menu includes different foods that are safe for you to eat. You may adjust the menu to fit your tastes and tolerance.

Breakfast
1 egg or 1/4 cup egg substitute
1/2 cup hot cereal
Mid-Morning
1/2 cup nonfat milk
Late Morning
1/2 cup chopped melon
Lunch
1/2 cup low-fat chicken noodle soup
Two Saltine crackers
Mid-Afternoon
1/4 cup low-fat cottage cheese
1/4 cup canned fruit packed in water or juice
Late Afternoon
1/2 cup sugar-free, nonfat yogurt
Dinner
2 ounces lean meat or fish
1/4 cup mashed potatoes
1/4 cup pureed or well-cooked vegetables
Bedtime Snack
1/2 cup nonfat milk

The sample menu offers eight small meals per day. You may wish to eat more or less often, but be sure to eat at least six times each day.

Remember to drink 1 cup of water or other non-caloric fluid between meals. It is important to take a multivitamin and mineral supplement daily, plus additional iron if required. In addition, you must take calcium and vitamin D supplements two to three times per day.

Recommended Meal Plan for Six Months Post-Surgery and Beyond

• Continue consuming 900 to 1,000 calories per day
• Decrease to three meals and only one to two snacks per day
• Discontinue taking high-protein liquid supplement drinks
• Increase the variety of low-fat, low-sugar and low-calorie foods, as tolerated
• Avoid raw vegetables, fresh fruits with skins, dried fruits, breads, popcorn, nuts and red meats only if poorly tolerated

Long-term Dietary Guidelines

Over time, you will be able to increase the variety and consistency of foods in your diet. Some foods may continue to be poorly tolerated, including red meats, chicken, breads, and high-fiber fruits and vegetables. Focus on low-fat, low-sugar and low-calorie foods and continue to count your calories every day. Try to meet your serving goals for all food groups based on the 900 to 1,000 calories diet plan described above.

To stay well hydrated, drink at least 2 liters of water or non-caloric fluids daily, unless this is contraindicated due to a medical condition.

Reviewed by health care specialists at UCSF Medical Center.
This information is for educational purposes only and is not intended to replace the advice of your doctor or health care provider. We encourage you to discuss with your doctor any questions or concerns you may have.