Ultimate Guide to the
Post Bariatric Surgery Diet

Have questions about the post bariatric surgery diet? I have your answers!

Here are answers to many, many, many common bariatric post op diet questions plus insider tips from a bariatric dietitian...me.

Post Bariatric Surgery Diet Stages

After gastric sleeve, gastric bypass, or gastric band, the post op diet progression consists of several stages to help you ease back into eating and prevent complications triggered by eating the wrong foods. Obviously you're not going to eat a steak right out of the gate!

You advance through a series of bariatric diet stages starting with clear liquids and slowly progress to solid foods over time.

Your surgeon will advance you though each phase of the bariatric diet progression. Each diet phase is slightly different from surgeon to surgeon. Follow your doctor's specific bariatric surgery post op diet instructions.

Why Cheating on Your Post Op Diet Isn't Smart

Cheating can cause side effects like:

  • Diarrhea
  • Dehydration
  • Constipation
  • Bowel obstruction
  • A very serious gastric leak

You Should Know

How long each bariatric diet stage lasts depends on how fast your body heals.

Everyone progresses at their own unique pace. Avoid comparing yourself to others.

Portion sizes depend on a number of factors.

Post Bariatric Surgery Diet:
Why Hydration is Key

Did you know…

…Dehydration is the #1 cause of readmission post bariatric surgery because it’s soooooo much harder to drink the necessary 64 ounces of fluid once you have a smaller stomach.

Before surgery, you may have been able to slam down a bottle of water in seconds flat when you felt thirsty. You simply can't do that anymore, especially in the first few days and weeks post op.

Your body’s need for fluid doesn’t change just because the size of your stomach is reduced with a weight loss surgery procedure.

What to Drink

Top 5 Water Tips: Strategies To Avoid Dehydration

It's possible to get dehydrated in as little as 1-2 days...which may mean a trip back to the hospital.

Why It's Important to Avoid Falling Behind

Every day that you fall short of your fluid goal, the deficiencies add up. You don't get a fresh reset everyday.

Fluid deficiencies are additive. That means if you only drink 50 ounces of water today, your goal tomorrow is the 14 ounces you missed + 64 ounces that you needed to begin with. That's then a total of 78 oz!  And it goes on and on.

The Truth About:




You may find yourself in a vicious cycle – with more dehydration, it becomes difficult to drink, and this leads to further dehydration.

While it's harder to drink 64 ounces of fluid every day after bariatric surgery, it’s possible with a little planning and great strategies.

Post Bariatric Surgery Diet:
Protein is the Foundation of the Diet

Eat your protein. Eat your protein. Eat your protein. This is your mantra after weight loss surgery, particularly in the "rapid weight loss"/"honeymoon" period. You need to know why you need so much protein after bariatric surgery!

How Much Protein?

60-80 grams covers the vast majority of people, but you may need more.  After all, we're all different. Protein requirements vary based on height, body composition, and activity level. A 6'2" man needs more protein than a 5'1" woman! If you’re over 6’ you may need as much as 100-120 grams of protein daily.

Discuss your unique protein needs with your surgery team. Follow your surgeon’s recommendation.

While there is no universal protein guideline that all bariatric surgery centers adhere to, 60-80 grams of protein per day is the commonly recommended range. However, many surgeons recommend more.

Why So Much Protein?

Best Protein Sources

Necessity of Bariatric Protein Shakes

With a new stomach the size of an egg or small banana (depending on which surgical procedure you have), and the inability to eat enough “real” foods in the beginning, the ONLY way to hit big protein numbers immediately post op, is to drink your protein.

Enter the “bariatric diet protein shake.”

Protein shakes are the foundation of the bariatric diet for at least the first couple of months post op. However, you gradually progress and add food sources of protein. You don’t need to live on protein shakes for your whole life!

Post Bariatric Surgery Diet:
You HAVE to Eat Mindfully...Or Else!

Once you’re able to start adding “real” foods back to your diet, learning how to eat mindfully is the single most important skill you need to master. Vomiting and severe discomfort can be caused by eating too fast, eating too much, and/or not chewing food well enough…in other words, eating mindlessly.

And if you're worried about eating eat too much, eating mindfully is the only real way to know your proper portion sizes.

Post Bariatric Surgery Diet:

Post Bariatric Surgery Diet:
The Bottom Line

Even though there is no standardized post bariatric surgery diet that all surgeons follow, there are some universal guidelines that are generally accepted: The 10 Commandments of Bariatric Eating.

Advance Through the Post Op Diet Stages at Your Own Pace

Stay Hydrated. Have a Plan to Prevent Dehydration.

Meet Your Protein Goal: Know Why. Start with Protein Shakes. Ultimately meet protein goal with real, whole food sources of protein.

Eat Mindfully

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