Prep for Bariatric Surgery:
Setting Realistic Expectations

Beside all the physical things you do beforehand, your prep for bariatric surgery should include setting realistic expectations around:

  • How much you can lose
  • How fast you can lose

Setting your goals too high (and thus not attainable or realistic) may set you up for disappointment, which could cause you to start eating like you used to. Healthy expectations are a key to success. Being realistic from the get-go is paramount.

Preparing for Bariatric Surgery:
How Much Can You Expect to Lose?

On average:

  • Gastric bypass patients lose about 70% of excess weight
  • Gastric sleeve patients lose about 60% of excess weight
  • Gastric band patients lose about 50% of excess weight

(Bariatric Surgery, A Systemic Review and Meta Analysis, 2004). This usually occurs in the first 1-2 years post op.

Note: Excess weight (EW) is your current weight (CW) minus your ideal body weight (IBW).


Let’ s say “Sally” weighs 325 pounds and her ideal weight is 140 pounds. That means she has 185 pounds of excess weight:

  • 325 - 140 = 185

If she had a gastric sleeve surgery, she could expect to lose an average of 60% of that excess weight:

  • 60% of 185 pounds = 111 pounds

Sally could therefore expect to end up at a final weight of 214 pounds:

  • 325 pounds –111 pounds = 214 pounds

Make sense?!

The calculation is based on average weight loss. Keep in mind, many people do better, and plenty of people do worse than the predicted numbers. Keeping track of what you eat, self-monitoring, exercising and being accountable can lead to above average weight loss results!

Start out with a realistic expectation. Calculate your expected weight loss here.

Prep for Bariatric Surgery:
How Fast Can You Expect to Lose?

What’s the weight loss timeline you ask?

I know, I know! You want the weight off yesterday. But patience little butterfly! It takes time.

The good news is that you’ll likely lose weight quickly in the first 1-3 months after surgery. However, anticipate that the rate of loss will gradually slow down. Because it will. Don’t freak out when it does. It doesn’t necessarily mean you’re doing something wrong.

Note: If you had a significant amount of preop weight loss, then you may not experience extremely rapid weight loss in the first few months.

It’s impossible to predict an exact weight loss timeline because everyone is different. Your age, gender, starting weight, activity level, how compliant you are with the diet and exercise recommendations, and which surgical procedure you have, all play a role in how fast and how much you lose. 

In My Personal Experience I Typically See:

2-10 pound average weight loss per week in the first 1-3 months

1-2 pound per week average after that

Weight loss drastically slows down or begins to stabilize after ~ 1 year

Prep for Bariatric Surgery:
You Need to Know Weight Loss Isn’t Linear

One thing I CAN guarantee, is that weight loss will NOT be linear. You may think it should be or hope it is. But it won’t be.

That means you won’t lose weight every single day, of every single week, of every single month. There WILL be times your weight loss stalls or your weight even goes up (!), despite the fact you’re doing everything right. What are you going to then? Throw in the towel because you’re disappointed in the numbers?

NO! You Better Not! That’s why knowing what to expect is so important.

Weight loss is an outcome. It follows healthy habits. Even when you’re not losing as much or as fast as YOU want to or YOU think you should be, just stick to your new healthy habits and your weight loss will eventually follow. It it’s not on YOUR weight loss timeline, don’t let that derail you!

Prep for Bariatric Surgery:
Setting Realistic Expectations -->The Takeaway

  • Starting off with unrealistic expectations will set you up for disappointment, which could cause you to revert back to old eating habits.
  • You can expect to lose 50-70% of your excess weight, depending on which surgical procedure you have.
  • Excess weight is the difference between your current weight and your ideal body weight.
  • If you opt for a gastric band you’ll normally lose a a little less and probably slower than those who have gastric sleeve (VSG) or gastric bypass (RNY).


  • Be aware that the rate of weight loss may start off fast, but it will likely slow down after just a few months. Don’t let it derail you when it happens!
  • How fast you lose weight depends on a number of factors including how many birthdays you’ve had, your gender, starting weight, activity level, how compliant you are with diet and exercise, and which surgical procedure you have.

Like this Info? Want More Like It? Let Me Join You on Your Journey!
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