How much weight will I lose after sleeve gastrectomy

Are you considering weight loss surgery but not sure how much you will lose?

Of course you are! It’s a perfectly normal question to have and one that every weight loss surgery candidate will ask. Often complicated by social media and the millions of before and after posts, it can be confusing to work out what to expect from your surgery. Here’s the deal…

Statistics tell us that you should expect to lose approximately 60% of your excess body weight (EBW) after a sleeve gastrectomy. Studies also tell us that this weight loss is well maintained for at least 5 years after surgery with the average weight loss at 5 years being more than 50% EBW.

Now, here we need a little bit of maths… (Steve, the surgeon in our clinic can do this in his head… but this is where I get out the calculator…)

What is excess body weight?

Excess body weight is the amount of weight that you have that is above what you would be if at a BMI of 25. So you need to work out what weight you would be at a BMI of 25, then minus that weight from your current weight. (Use this BMI calculator to work out the weight for your height at a BMI of 25. Use the higher number in the line that says “Based on the healthy BMI recommendation…”)

Then, once you have your excess body weight, you need to work out 60% of that.

So,

(Current weight – Weight at BMI 25) x 0.6 = Estimated weight loss after surgery.

Keep in mind that 60% is an average. There are people who lose less and some that lose more, even getting back under a BMI of 25 in some cases. Ultimately, success from a sleeve gastrectomy comes from setting the proper expectations and making a decision and effort to change your habits.

If your number seems lower than expected, do not get upset. Try not to compare yourself to everyone else on the forums – each journey is different. It’s also important to think of all the other benefits of surgery such as coming off medication, improving your mobility and quality of life and lengthening your life.

Can I lose more?

Some people will lose more than this estimated weight. People most likely to lose more than this are those who are:
• Younger (<40)
• Active and include strength training
• Healthy before the surgery (without too many co-morbidities)
• Make great mindset changes

Why might I not lose that much?

It’s true that some people don’t lose as much as the 60-% EBW. Usually these are the people who:
• Have already had some weight loss surgery (e.g. a band)
• Are not very active
• Are older
• Have other medical conditions such as PCOS, thyroid issues, depression, or
• Take medication that promotes appetite and weight gain like some anti-psychotics or anti-depressants
• Are not able to make the necessary changes to their eating habits

All of these are just things to take into consideration, and don’t necessarily mean you will be unsuccessful. Discuss them all with your surgeon and dietitian as part of your pre-op visits as they will be able to give you more personalised advice.