Post-Bariatric Surgery Diet: What You Can Eat

Best foods for your ‘new’ stomach

When you undergo gastric bypass, a common weight-loss surgery, your stomach loses about 80% of its size, and there are changes in your small intestine. Now, you have to be more strategic about what — and how — you eat and drink. It’s about concentrating on nutritious foods and staying well-hydrated. You’ll be able to tolerate some foods better than others as your digestive system shifts. See what dietitians recommend to patients immediately after, in transition and as eventual routine habits following bariatric surgery.

Water and protein shakes: immediate post-operation

Hydration and protein are top priorities after weight-loss surgery. “In our clinic, we typically have patients stay on a full-liquid diet, which is protein supplements and lower-sugar drinks, for about two weeks out from surgery,” says Patricia Morrison, a registered bariatric dietitian and bariatric program coordinator at UT Southwestern Medical Center. You drink enough water to avoid dehydration in amounts you can tolerate, depending on your postoperative swelling. That initial amount could range from about 50 to 80 ounces a day, she says. Additionally, protein shakes help your body recover and heal.

Soft foods: transition

After about two weeks, you start on soft foods. “It’s any kind of food that has a soft texture,” says Lauren Sullivan, a clinical registered dietitian for the Center for Human Nutrition and the Bariatric and Metabolic Institute at Cleveland Clinic. “It’s easily cut with a fork or knife. The focus is on high-protein items.”

Dietary recommendations may vary depending on your type of weight-loss surgery. Roux-en-Y gastric bypass (the official name), sleeve gastrectomy, adjustable gastric band and biliopancreatic diversion with duodenal switch are all types of bariatric procedures. How long you stay on a soft food diet will also depend on the procedure, but it’s usually a couple months or more.

Eggs and yogurt

Soft-cooked eggs or egg-white products like Egg Beaters provide protein in a form people can easily handle. Greek yogurt or cottage cheese are good dairy sources of protein. Food quantities are significantly smaller than what you were used to before surgery. “The usual volume, for most patients, when they start softer food is about 2 ounces or one-quarter cup,” Morrison says. “It may not even be one full egg, for instance.”

Food density is a factor in portion size, she says. Eggs are denser than Greek yogurt, so you can have a larger portion of the latter. Meals are smaller and more frequent. You’ll likely eat at least four times a day with a couple protein supplements in between. While meal spacing depends on the patient, Morrison adds, it’s important to take in certain amounts of protein, fats and calories throughout the day.

Fish, sliced poultry and tofu

Tuna and other soft, flaky fish can be seafood sources of protein following bariatric surgery, Sullivan says. “The way that we at Cleveland Clinic progress (patients) is very gradually, over several months,” she says. In this early phase, it’s difficult to get more volume in, often because of swelling from surgery. So protein-rich foods are a must. Another choice could be soft turkey breast sliced very thinly so it’s easily cut. Tofu is a non-meat, easy-to-chew alternative, she adds. That’s important, because you’ll have to eat more slowly and chew food more carefully to avoid problems like regurgitation. Steak and other fibrous foods may persist in posing a problem.


Soft-cooked veggies such as carrots or green beans — like those you might include with a roast — are easier to eat at first. “It would be any low-carbohydrate vegetable,” Sullivan says, and so you wouldn’t choose corn or peas. Raw celery and cabbage are too fibrous, and it’s not necessarily the best time to incorporate salad into your diet. Once softer vegetables are easily tolerated, patients can try coarser, raw vegetables, but they have to be chewed very well, she adds. Soft or peeled fruit could also work.

Healthy variety: new normal

You have a chance to learn about dietary and other changes well before undergoing weight-loss surgery, and you receive ongoing support afterward. “There’s a huge process that goes on ahead of time, trying to get patients prepared before surgery,” Sullivan says. “And there’s an even bigger process after surgery, helping patients become confident in what they have to do for the rest of their life.”

Some recommendations are similar to what dietitians stress for anybody: Concentrate on whole foods, produce and lean protein sources; eat whole grains such as brown or wild rice and quinoa or farro versus white rice, pasta or bread; and avoid processed snack foods (even high-protein snacks). However, there are also specific foods that you’ll likely limit for better nutrition and to feel as good as possible. A major example: Sugar absorption can change after gastric bypass, and a piece of birthday cake with frosting could lead to a condition called dumping syndrome with symptoms such as diarrhea and cramping.

Plenty of fluid

Water is always a must to stay hydrated, and you can add some variety to it. For instance, you can drink enhanced water (like Vitamin Water Zero) that’s sweetened with stevia rather than chemical sweeteners, Sullivan explains. You can also squeeze some lemon or lime juice to flavor water. Caffeine should be avoided in the early postoperative period, because it acts as a diuretic. “The No. 1 reason for readmission after bariatric surgery is dehydration,” she adds. “So we want to be careful of that until patients are able to consume about 2 liters of water a day.”

Nonsugary drinks

Once you can take in enough fluid to avoid dehydration, adding caffeine back into your diet is fine, Sullivan says. But don’t add a spoonful of sugar to your coffee or tea. Sugary drinks are out: Soda, sweet tea and juices aren’t the best choices after gastric bypass. Although they might be OK in small amounts, Morrison says, having sugar-sweetened drinks on a regular basis can contribute a lot of calories and lead to weight gain or poor weight loss.

Carbonated beverages like diet soda can be tricky for bariatric patients. Bubbly drinks can cause discomfort because there’s less space in the stomach for bubbles to expand, she says. “After the healing phase, if they want to have a bubbly drink of some kind, for celebratory reasons on a rare occasion, it’s usually OK in small amounts,” Morrison says. “But not all people will tolerate it.

Alcohol-free beverages

Alcohol is not recommended after bariatric surgery because of its calorie content and higher risk of dependency, based on research comparing groups of those who either have or haven’t undergone gastric bypass. For example, one study following patients several years after they had gastric bypass found increased prevalence of alcohol use disorders, particularly in men. One issue is that your body now absorbs much more alcohol than it used to. “The equivalency is, for example, if you’re drinking a glass of wine after surgery, the effect on the blood alcohol level is as if you were drinking three glasses of wine before surgery,” Sullivan says. If you drink any alcohol after bariatric surgery, do so sparingly.

Dairy in moderation

“We usually just have patients target moderate-fat dairy products,” Morrison says, rather than choosing fat-free dairy. For example, she says, 2% Greek yogurt is a good protein source that goes down well. If you choose whole-fat dairy, such as sour cream, cottage cheese or cheeses, pay closer attention to serving size, she advises. Milk isn’t ideal, she says — in general, it’s preferable to limit most high-calorie or filling liquids.

Careful calorie boost

As you gradually settle into your new eating pattern, you’ll actually reach the point where you need to add calories. “Some of our patients feel like if they’re eating 600 to 1,000 calories a day, that’s where they’re always going to be,” Sullivan says. “When we start to ask them to increase the calories to between 1,200 and 1,500 at two, three or four years out of surgery, it’s scary because they’ve been accustomed to battling weight their whole life. And the only way they’ve been able to take weight off is restricting.” Now, she tells patients, “Nope, we don’t want you to restrict anymore — we have to get those nutrients in.” Plant-based oils like olive and sunflower oil, avocados, nut butters and whole olives, sunflower seeds and nuts are great ways to bump up calories, she says.

Vitamin and mineral supplements

Because you’re at higher risk of nutritional deficiencies, vitamin and mineral supplements are recommended after bariatric surgery. “Even if you’re eating really well, when you’ve had this type of operation, you don’t absorb all your vitamins and minerals,” Morrison explains, and you’re also having much smaller food portions. Usually, she says, patients take two complete multivitamins with iron, an extra dose of calcium and vitamin D and sometimes extra vitamin B12 as well.

Post-bariatric surgery foods

Here’s what to eat and drink after weight-loss surgery:

— Water.

— Protein shakes.

— Soft, cooked veggies.

— Eggs.

— Yogurt.

— Flaky fish like tuna.

— Thin-sliced turkey breast.

— Tofu.

— Soft, peeled fruits.

— Whole grains.

— Unsweetened, non-bubbly beverages.

— Moderate-fat dairy.

— Plant-based oils.

— Avocado.

— Olives, sunflower seeds and nuts.

— Vitamin and mineral supplements.

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