Gastric Sleeve Surgery for Patients with Low Initial BMI (BMI 30-34.9)

Post updated February 2021.

Recently, I updated my post Weight Loss Surgery for Low BMI Patients (BMI 30-34.9) based on updated guidelines from several leading organizations. These guidelines answer the question, “Is weight loss surgery an appropriate treatment for people with mild obesity (BMI less than 35)?” 

When I first wrote that post in 2012, the answer was “yes!” I would describe the updated guidelines as now saying “YES!” (I covered the guidelines in detail here.)

Additionally, since I first wrote that post, there are many more published studies that support weight loss surgery for individuals with mild obesity (BMI 30-34.9).

Sometimes I get asked why something as drastic as surgery could be a smart option for people who “only” have 50-75 pounds to lose. They wonder if that’s “necessary.” Shouldn’t diet and exercise work?

According to published scientific literature, diet and exercise programs do not result in weight loss that lasts – no matter how much weight a person has to lose.1,2 I encourage you to read my blog post about the body weight set point in order to learn more about why diet and exercise are not effective long-term for weight loss.

Gastric sleeve is the most popular weight loss operation for patients with mild obesity (BMI less than 35)

Currently, the two most common options for weight loss surgery are the gastric sleeve operation, and the gastric bypass operation.

There are other operations, most notably the LAP-BAND® operation, and the duodenal switch.

The LAP-BAND®, or gastric banding, was popular in the past, but has now largely been abandoned as a weight loss operation because long-term research shows that it can lead to complications, and that it’s not as effective as other weight loss surgeries.  

The duodenal switch works great for weight loss, but it is more invasive and higher risk than gastric bypass and gastric sleeve. Because of the higher risk of complications, it hasn’t gained widespread popularity in the United States.

The gastric bypass is a great operation for weight loss, but it is more invasive and higher risk than the gastric sleeve. In lower BMI patients—who are generally at less medical risk from obesity than higher BMI patients—the least invasive and lowest risk operation, the gastric sleeve, is typically favored. (Read my blog post entitled Sleeve Gastrectomy Dominates the Field of Weight Loss Surgery.)

What does the published literature say about gastric sleeve surgery for people with low BMI obesity?

Many studies have been published on gastric sleeve surgery in low BMI patients. These published studies all show the gastric sleeve operation to be safe and effective for low BMI patients. Here are 3 of the more significant studies.

  1. Is it worth it? Determining the health benefits of sleeve gastrectomy in patients with a body mass index <35 kg/m23

    Comment from Dr. Oliak – the quick answer? Yes! This is a great study that looked at all the low BMI patients in Michigan who had the gastric sleeve operation in 2006-2018 (1073 patients). The data showed a high rate of improvement of medical issues (60% of patients off hypertension meds, 64% off insulin, 79% off diabetes oral meds), low complication rates, 72% excess weight loss (EWL) at 1 year, 90% of patients report being “very satisfied”. The study concludes that the operation is safe and effective in the low BMI patient population.

  2. Sleeve Gastrectomy Outcomes in Patients with BMI Between 30 and 35 – 3 Years of Follow-Up4

    Comment from Dr. Oliak – this is a relatively long-term follow-up study (most studies have less than 3 years follow-up) that found low complication rates, no leaks, 83% EWL at 2 years, and a high rate of resolution of weight-related medical issues in 252 low BMI sleeve gastrectomy patients. This study concludes that gastric sleeve surgery is safe and effective in the BMI 30-35 patient population.

  3. Results of Laparoscopic Sleeve Gastrectomy in 541 Consecutive Patients with Low Baseline Body Mass Index (30-35 kg/m2)5

    Comment from Dr. Oliak – This is another great study (541 patients) that shows excellent average weight loss results (78% EWL at 1 year) and low complication rates (leak 0%, bleeding 1.2%) in low BMI people who underwent sleeve gastrectomy surgery. This study also concludes that gastric sleeve surgery is safe and effective in the BMI 30-35 population.

Our Gastric Sleeve Outcomes in Low BMI Patients (BMI 30-34.9)

We’ve been performing weight loss surgery for low BMI obesity patients in Orange County since 2003. The 260 surgeries we’ve performed for low BMI obesity patients specifically are:

  • 19 gastric bypass
  • 166 gastric banding (none since 2013, because of reasons stated above)
  • 75 sleeve gastrectomy

However, that number is growing. We mostly do gastric sleeves for people BMI 30-34.9. We do occasionally perform gastric bypass for people with low BMI obesity under certain circumstances like diabetes or severe acid reflux, or in the case of revision surgery.

Our results with sleeve gastrectomy for patients with mild obesity in Orange County are similar to the results in the studies above. The sleeve operation is safe, and these patients achieve excellent weight loss. 

In fact, most studies show better weight loss results (in terms of percent excess weight loss – %EWL) for people with low BMI obesity than other, more overweight populations—industry average weight loss is typically 55-60% EWL for people with a higher BMI. In the lower BMI population (BMI 34-34.9), our results and the results published in the 3 studies above are better, averaging 70-90% EWL.

Details of our low BMI gastric sleeve patient population are as follows: total number of patients to date 75, 89% women, 11% men, average starting weight for women 197 pounds, average starting weight for men 247 pounds.

Our gastric sleeve outcomes in low initial BMI patients have been excellent. Our BMI 30-34.9 patients average 87% EWL (excess weight loss) at 1 year postop, 82% EWL at 2 years postop, and 78% EWL at 3 years postop.*

Our BMI 30-34.9 female patients average starting weight is 197 pounds, and their average weight at 1 year after surgery is 142 pounds.*

Our gastric sleeve complication rates in low initial BMI patients are low. Our gastric sleeve leak rate is 0%, our gastric sleeve bleeding rate is 0%, our 30 day readmission rate is 0%, and our 30 day reoperation rate is 0%.* We’ve had 3 late reoperations, 1 for gallbladder removal due to gallstones, and 2 for hiatal hernia repair.*


The gastric sleeve operation may be a reasonable option for patients with lower starting body mass index (BMI 30-34.9, generally 50-75 pounds over ideal weight) who have been unable to lose weight and maintain weight loss using nonoperative methods.

Published studies, and our patient data, show excellent weight loss results and low complication rates in the BMI 30-34.9 population over the short and medium term, and therefore support the use of sleeve gastrectomy in this group of patients.

Learn More

Learn more about Los Angeles and Orange County bariatric surgeon Dr. Oliak and his weight loss surgery program.

* Patient outcomes vary after weight loss surgery. Past outcomes may not be indicative of future results. 


  1. Doctors Need to Focus Less on a Patient’s Weight. Scientific American, Feb. 2020,
  2. Brown H. It’s Time to Stop Telling Fat People to Become Thin. Medical Examiner, Mar 24 2015,
  3. Varban OA, Bonham AJ, Finks JF, et al. Is it worth it? Determining the health benefits of sleeve gastrectomy in patients with a body mass index <35 kg/m2. Surg Obes Relat Dis. 2020 Feb;16(2):248-253
  4. Berry MA, Urrutia L, Lamoza P, et al. Sleeve Gastrectomy Outcomes in Patients with BMI Between 30 and 35-3 Years of Follow-Up. Obes Surg. 2018 Mar;28(3):649-655
  5. Noun R, Slim R, Nasr M, et al. Results of Laparoscopic Sleeve Gastrectomy in 541 Consecutive Patients with Low Baseline Body Mass Index (30-35 kg/m2). Obes Surg. 2016 Dec;26(12):2824-2828

More Weight Loss Surgery Resources


David Oliak, M.D.

Dr. Oliak is a board-certified, fellowship-trained surgeon who specializes in minimally invasive (laparoscopic and robotic) weight loss surgery. He has been in practice in Orange County, California, since 2002, has completed more than 3000 weight loss operations, and has a track record of excellent patient outcomes.*

Dr. David Oliak is the founder of the Oliak Center for Weight Loss. He started the Oliak Center because he wanted to provide weight loss surgery done right. His commitment has always been to provide the kind of care that he himself would want to receive. Dr. Oliak is affiliated with only the best bariatric hospitals and surgery centers in Los Angeles County and Orange County.

* Individual patient results vary. Past performance is not a guarantee of future results.

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