Diet After Gastric Bypass: Your Nutrition Guide

Your diet after gastric bypass will look very different from your diet now - and that’s a good thing! You’re going through this procedure to care for your health, and it makes sense that you’ll want to carefully and deliberately protect your health moving forward.

Today, we’ll go through an overview of the after gastric bypass diet, including general nutrition and hydration tips. You’ll learn what to watch out for, how to make sure you get all of your macronutrients, and whether you’ll need to take any vitamins or supplements after surgery.

Getting a gastric bypass is an intense process. During this time, it’s important to be gentle with yourself and make sure your body gets everything it needs. So let’s start by reviewing what your body will require after your surgery.

What does your body need after a gastric bypass?

Your diet after gastric bypass will require a little more thought than your pre-gastric bypass diet did. The main reason for this has to do with the way your body processes food.

Your stomach is a muscle. It dissolves food into building blocks using both natural acids and muscle contractions. Gastric bypass surgery removes part of your stomach, which impacts its ability to break down food the way it did before.

Different parts of the stomach also absorb different nutrients. A smaller stomach means that your body will have a harder time absorbing your nutrients.

This means that in addition to changing your diet after gastric bypass, you’ll need to take vitamins to make sure your body gets everything it needs to stay healthy.

Last but certainly not least, make sure to stay hydrated. Your body is up to 60% water, and it loses some of that water during many different processes – like urination, sweating, and, yes, healing after surgery.

Stay hydrated

When talking about diet after gastric bypass, there’s one thing to keep at the front of your mind. Your body is recovering from surgery. Your first few weeks in recovery will be very much like recovering from any other major surgery: lots of rest and lots of fluids.

Your body can heal more quickly when you’re hydrated, but many people find it difficult to stay hydrated after gastric bypass surgery.

Since your stomach can hold less, consistency with hydration is crucial. Rather than drinking full glasses of water throughout the day, keep water nearby and take tiny sips regularly.

This is especially important immediately after your operation - since your stomach will be swollen and will be able to hold even less than normal.

Immediately after your surgery, you’ll be on the bariatric liquid diet. While this will support hydration, don’t let your meals do the heavy lifting! Make sure you’re drinking plenty of water, not just the liquids you’re consuming at mealtimes.

Aim for 48-64 ounces of water a day, especially right after gastric bypass surgery.

Take supplemental vitamins & minerals

After water, vitamins and minerals are the most important things to incorporate into your diet after gastric bypass surgery. Your body is made up of many different tiny “building blocks.” Some of these it builds for itself, but others it needs to get from food.

You can think of it like LEGO bricks. You can create a brick that’s 6 studs long by using two 3-stud pieces. Or three 2-stud pieces. Or six 1-stud pieces. But you can’t create a 1-stud piece out of something else.

Your body works similarly. It can rearrange different “pieces” that it gets from food, but your food spends less time in your stomach after gastric bypass surgery. Less time in your stomach means less time for your body to absorb all the macro- and micro-nutrients it can’t build for itself.

This means you’ll need to supplement with them religiously to make sure your body gets everything it needs in your after gastric bypass diet.

You’ll also need to watch for signs of vitamin deficiencies since these can be life-threatening if not treated. Taking liquid bariatric vitamins can prevent deficiencies, as well as eating foods that are high in vitamins and minerals.

There are more than two dozen micronutrients our body processes. Fortunately, there are only a few you’ll need to supplement your diet after gastric bypass surgery.

As a starting point, your vitamins after gastric bypass should include:

Iron – 18 mg
Folic acid – 400 mcg
Selenium – 400 mcg
Copper – 400 mcg
Zinc – 400 mcg
Calcium – 1,200 to 2,000 mg, taken in three doses throughout the day for best absorption
Vitamin D – 800 to 1,000 International Units (IUs), taken in two doses
Vitamin B12 – 500 mcg

Take your vitamins as prescribed and work with your doctor to determine the best dosage.

Six months after surgery, you can begin to look for high-vitamin foods to incorporate into your regular diet.

Diet after gastric bypass surgery

Now that we’ve covered hydration and vitamins, it’s time to talk about your diet. It’s important to ensure you’re getting the proper nutrient intake with the correct balance of fats, carbs, and protein in your after gastric bypass diet.

Fats in your diet after gastric bypass surgery

First off, don’t worry: Eating fat doesn’t cause you to gain fat in your body. The “fat will make you fat” myth is just that – a myth. This belief was spread in the 1970s, and health science has come a long way since then.

The truth is that your body needs fats, particularly “healthy” – or unsaturated – fats. Fats allow your body to regulate metabolism, store energy, keep your immune system strong, and help proteins do their job.

In your diet after gastric bypass, your relationship with fats will change slightly. Digesting fats is more difficult for your body after the surgery. This is part of the reason you lose weight so quickly, but it can also cause health problems.

After your surgery, eating too much fat will make you feel nauseous and may even give you Steatorrhea – a kind of diarrhea caused by unabsorbed fat moving through the digestive system. This is the reason your early diet after gastric bypass will be largely fat-free.

While your body is still healing, fat is too difficult for it to process, so it’s more likely to cause discomfort and complications.

Once you’ve healed a bit, you’ll need to start re-incorporating those healthy fats. Without any fat in your diet at all, your body won’t be able to absorb the fat-soluble vitamins it needs. As such, your immune system would weaken, and your skin, hair, and eyes would suffer!

The key to fat in your diet after gastric bypass is sticking to guidelines like the ones your healthcare team gives you.

Aim for around 45 grams of healthy fats each day, about 10% of your total protein intake. Each serving of food you eat should contain no more than 5 grams of fat.

Balancing carbohydrates after a gastric bypass surgery

Much like fat, carbohydrates (often just called “carbs”) tend to get lots of blame for unwanted weight gain. Many people even get told that carbs are “evil!”

However, just like fats, your body needs carbohydrates.

So how do you heal your relationship with carbs in your diet after gastric bypass surgery? Remember what the job of carbs is – providing quick energy.

Protein and fats are great sources of energy for your body. But, paradoxically, they take time and energy to break down. Your body doesn’t always have the time to spend on getting energy from fat and protein.

That’s where carbs come in.

Carbs give your body a boost because they break down into glucose quickly. This is why highly processed carbs will spike your blood sugar, even if what you ate was something like pasta or pizza.

So what can you eat after gastric bypass to make sure you meet your carbohydrate needs?

Your diet after gastric bypass will need healthy, complex carbs. These are carbs that are high in fiber, like lentils, chickpeas, black beans, oats, almonds, and quinoa. You’ll also want to include a few starches, like potatoes, corn, peas, whole wheat, brown rice, quinoa, and bulgur.

After your gastric bypass, aim for…

0-4 weeks post-op: Few to no carbs. This allows your body to use a high-protein intake and previously stored energy to heal.
1-6 months post-op: 80-90 grams of carbs each day. Aim to make most of your carbs complex, but some of them can come from whole fruit.
6 months post-op and beyond: 100 grams of carbs each day. Aim for at least 20 of these to be fiber, and whole fruit is still okay.

Now that we’ve covered the proper fat and carb intake after a gastric bypass, it’s time to discuss protein.

Protein needs after a gastric bypass

Protein is the foundation of your diet after gastric bypass surgery.

At the most basic level, all of your cells are made of protein. Protein will likely be one of the first things you discuss with your health team, and any bariatric-friendly snacks should be high in protein.

So why do you need to include so much protein in your diet after gastric bypass?

Your body contains at least 10,000 different kinds of proteins. Some are building blocks your body can make for itself. Others, your body needs to get from food.

Even the proteins your body can make for itself require more time and energy to create. And expending even more energy is the last thing a healing body needs. This means that the protein you eat should be easy for your body to digest and rearrange.

Immediately after your surgery, your healthcare team will recommend meeting your protein needs with either a liquid or powder supplement. Supplements are extra-gentle on your still-healing stomach, and some protein supplements are optimized for digestibility, as well.

Speaking of being gentle to a healing stomach, avoid whey protein wherever you can. Your diet after gastric bypass changes because your stomach is more sensitive. Even for people who haven’t undergone gastric bypass, whey protein can be too tough for your body to handle.

Instead, look for collagen protein, which is gentler on all stomachs!

But why does your body need all this easy-to-access protein in the first place?

When you don’t get enough protein, your body takes longer to heal, but that’s just the beginning. Gastric bypass patients who don’t get enough protein are more likely to lose muscle, not just fat. You’ll also likely have more loose skin, some hair loss, and experience dumping syndrome more often.

Even after you’re fully healed, protein is one of the most important parts of your diet after a gastric bypass.

You’ll need to make sure you get 60-80 grams of protein every day, starting as soon as possible after surgery.

Making the most of your after gastric bypass diet

Congratulations! You’re making a big choice for your health, and you’re committed to sticking with it for the rest of your life. Gastric bypass isn’t an easy process, and you’ve probably already gone through multiple consultations and appointments to get here.

Now, you’re expecting to make changes to your diet after gastric bypass. The most important change you can make will be the way you view food. From this moment on, think of food as building blocks for your health – not roadblocks.

You’ll always need food. And your diet after gastric bypass will be all about giving your body what it needs: water, vitamins & minerals, fats, carbohydrates, and plenty of easily-digestible protein. After you’re done healing, the majority of these things should come from food.

When it comes to protein, however, it’s hard to get enough in a single day - especially with a reduced stomach size. Adding a high-quality hydrolyzed collagen protein supplement will help you meet your health goals and be comfortable in your own skin for years to come.