Gastric Bypass Gastric Sleeve Post-op

Expected Weight Loss after Bariatric Surgery

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The amount of weight you lose will depend on the kind of bariatric surgery chosen as well as on the conscious lifestyle alterations made by you by increasing your physical activity levels and eating well. Not committing to lifestyle changes will make you regain the weight lost. However, it is important to have reasonable weight loss goals.

To be called a bariatric surgery success, you will have to keep off more than half of the excess weight lost. Excess weight lost is the fastest after gastric bypass surgery, followed by gastric sleeve and lap band surgery.

After Gastric Sleeve Surgery

  • Individuals with gastric sleeve lose about 18 % percent of excess body weight in the first month. 1
  • Average excess body weight loss by the end of 6 months is nearly 50%.
  • By the end of the first year the average excess body weight loss is 63%.

Studies at a Glance: 

  • In a 2013 study published in the journal Surgery for Obesity and Related Diseases gastric sleeve patients with an average BMI of 43 were covered. The mean follow up was 5.9 years.2
  • The average excessive BMI lost over 5 years was 57.4%. The first year reported considerable weight loss with decreased but stable weight loss in the subsequent years post surgery.
  • The study concluded that the average excessive BMI lost was:
    • 5% (12.6 kg/m2) after 1 year
    • 1% (12.4 kg/m2) after 2 years
    • 4% (11.2 kg/m2) after 5 years
  • The report also concluded that sleeve gastrectomy is effective in reducing nearly 60% of excessive BMI and results in complete remission of co-morbidities in patients after almost 6 years.
  • Another study by Vincent W. Vanek was conducted on two groups of morbidly obese patients – one was treated with diet and the other went through gastric sleeve surgery. 3 The results showed that the prior group lost 2% of the excessive BMI and the latter lost 27% over a median follow up of more than 15 years.

After Gastric Bypass Surgery

  • Studies show that patients lose about 30% to 40% of their excess body weight in the first 6 months, post gastric bypass.4
  • Within one year of the surgery many patients lose a considerable amount of excess BMI and are quite close to their goal weight.
  • The stomach pouch usually stretches after 21 months to hold more food which stabilizes weight loss.
  • Overall, the average excess body weight loss by patients is about 60%. For instance, a person weighing 350-pounds (who weighs 200 pounds extra) would drop about 120 pounds.5

A dose of weight loss motivation to help you reach your target.

 Bariatric Surgery Motivation


  1. Marcy Brinkley; Expected Monthly Weight Loss with the Gastric Sleeve;
  2. Kristina Fiore; Gastric Sleeve Works Long Term, MedPage Today;
  3. Vincent W. Vanek, MD, FACS, CNSP; Laparoscopic Bariatric Surgery;
  4. Weight Loss Surgery: What to Expect the First Year; WebMD Feature Archive
  5. What Is Gastric Bypass Surgery? WebMD Medical Reference


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US-registered Bariatric Dietitian

US-registered Bariatric Dietitian
Katelyn Mock is a US-registered Bariatric Dietitian certified by the American Academy of Nutrition and Dietetics. With more than 8 years of experience in formulating and reviewing diet programs across various hospital settings, Katelyn has also served as the Lead Bariatric Dietitian for the Ohio State University Medical Center.

On-site Bariatric Nutritionist in Tijuana