What Do You Know About Metabolic and Bariatric Surgery and Nutrition?

Savannah Helm

By Alicia Jerome MS, RDN

The first bariatric surgery was performed in the 1950’s, but it was quite different from the type of surgery performed today.1 Originally, much of the small intestine was bypassed leaving the stomach intact but causing malabsorption. Much was learned from that first surgery, but most procedures have greatly improved. Some aspects of bariatric surgery have persisted – for better or for worse.

According to Melissa Majumdar, MS, RD, CSOWM, LDN, co-author of the Academy’s Pocket Guide to Bariatric Surgery, 3rd edition2 in a personal interview, one of the positive changes for the field is in the name. Bariatric surgery is now called Metabolic and Bariatric Surgery to show a broader scope of practice than just concern about a patient’s weight.

According to the American Society of Metabolic and Bariatric Surgery (ASMBS), the largest national society for the specialty, there were 256,000 bariatric surgeries in 2019.3 That is a 62% increase since 2011. Of those surgeries, the sleeve procedure makes up the largest percent with 59%.3

Answers to Common Questions, according to Melissa:

  • In the perfect world, metabolic and bariatric patients would do what? Seek help earlier knowing that a metabolic & bariatric program is a safe space with their needs in mind.
  • In the perfect world, metabolic and bariatric dietitians would do what? Ideally, RDNs would continue to collaborate, use varied resources, and attend meetings to network and share ideas.
  • What does the non-bariatric dietitian need to know about bariatric nutrition?

Currently there is a stigma within dietetics about weight loss and bariatrics. RDNs see very sick patients in the ICU, and if they happen to see a bariatric patient in that setting, they think they represent the norm. Unfortunately, they are not seeing patients at their best or healthiest. Metabolic and bariatric surgery is a lifesaving procedure to improve one’s quality of life.

If a non-bariatric dietitian counsels a post-op patient, they should be comfortable discussing smaller volumes of food, stressing the importance of micronutrient supplementation and evaluation, and working with patients on their vitamin regimen. The non-bariatric dietitian should also consider giving more focus to non-scale victories (NSVs) to help lessen the emphasis on what the weight scale says.

Who Qualifies for Bariatric Surgery? What Metabolic Issues Are Considered?

To qualify as a candidate for bariatric surgery, a person must meet the universal standards established by the National Institutes of Health (NIH).4 These include:4

  • Body mass index (BMI) ≥ 40 or 100-pounds overweight
  • BMI ≥ 35 and at least one or more obesity-related co-morbidities such as type II diabetes (T2DM), hypertension, sleep apnea and other respiratory disorders, non-alcoholic fatty liver disease, osteoarthritis, lipid abnormalities, gastrointestinal disorders, or heart disease
  • BMI ≥ 30 or more with type 2 diabetes that is difficult to control with medical treatments and lifestyle changes

Some practitioners are actively calling for a revision since standards were established in 1991 and more research and statistics are now available. Some push for the standards to include a lower BMI for those with metabolic issues. Why wait for the comorbidities to show up when action can be taken now?

For example, Melissa explains that if diabetes patients can have bariatric and metabolic surgery within seven years of a diagnosis and prior to the need for insulin, they can put their diabetes into remission. An excellent health reason for revising the standards.


Once a patient meets the objective standards, they are then enrolled in a 6–8-month pre-operation program at an accredited hospital with a skilled multi-disciplinary team including a registered dietitian. The patient will undergo a psychological evaluation, learn macro-/micro-nutrient planning, participate in psychological counseling plus many other skills to set up their long-term path for metabolic health. Patients who successfully meet all these criteria are then able to schedule their surgery date.

Insurance Coverage

Another area that has seen some change but still needs more is insurance coverage. January 2022 was the first-time Texas state employees had the benefit of bariatric surgery insurance coverage.  While each metabolic and bariatric program requires the patient to receive nutrition counseling, it is not typically covered by insurance, which makes no sense.

Benefits to the Patients

The benefits for the patient following metabolic and bariatric surgery are staggering. The ASMBS state that patients “may lose as much as 60% of excess weight six months after surgery, and 77% of excess weight as early as 12 months after surgery.”5 There are also impressive remission rates for hypertension (75%), obstructive sleep apnea (96%), dyslipidemia (76%), and cardiovascular disease (58%) in addition to the remission of diabetes (92%) mentioned above.4 According to Majumdar, other benefits include most patients reduce up to 50% of their usual medications for hypertension and 75% of insulin following the surgery. Of course, one of the greatest benefits of a successful surgery is the extended years of healthy life for the patient.6

Post-Surgery Nutritional Implications

After surgery there is a heightened focus on the patient’s digestion and absorption, not only with their food but specifically with their vitamins and minerals. A vitamin and/or mineral deficiency is the number one risk for patients, yet it is completely preventable. Patients will continue a life-long micronutrient protocol to prevent deficiencies as well as adapt to smaller portion sizes. The plan is for patients to come back regularly for checkups on their nutrition, mental health, physical healing, etc.


With each passing year, the field of metabolic and bariatric surgery will continue to grow and see more changes. And with that growth, comes the opportunity for more patients to live longer, health-filled lives.

Want to learn more? The Academy of Nutrition and Dietetics Pocket Guide to Bariatric Surgery, 3rd edition CE course is now available here!

The 3rd edition includes more information on endoscopic procedures, the adolescent population, enteral and parental nutrition, and it has a guide for diet progression post-surgery. This pocket guide continues to be the number one resource for most bariatric dietitians.

Co-editor, Melissa Majumdar, MS, RD, CSOWM, LDN is the bariatric coordinator for Emory University Hospital Midtown, and chair of the Integrated Health Planning Committee for the American Society for Metabolic and Bariatric Surgery. Kellene Isom, PhD, MS, RD, CAGS, is an assistant professor of nutrition at Cal Poly Pamona, a nationally recognized speaker on metabolic and bariatric surgery and co-editor on this bariatric pocket guide.


  1. Story of obesity surgery. American Society for Metabolic and Bariatric Surgery. (2014, May 27). Retrieved June 22, 2022, from https://asmbs.org/resources/story-of-obesity-surgery
  2. Weight Management DPG, Isom K, Majumdar M, editors. Academy of Nutrition and Dietetics Pocket Guide to Bariatric Surgery, 3rd edition. Academy of Nutrition & Dietetics: Chicago, IL; 2022.
  3. Estimate of bariatric surgery numbers, 2011-2019. American Society for Metabolic and Bariatric Surgery. (2021, March 8). Retrieved June 13, 2022, from https://asmbs.org/resources/estimate-of-bariatric-surgery-numbers
  4. S. Department of Health and Human Services. (n.d.). Weight-loss (bariatric) surgery. National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved June 13, 2022, from https://www.niddk.nih.gov/health-information/weight-management/bariatric-surgery
  5. Metabolic and bariatric surgery fact sheet: ASMBS. American Society for Metabolic and Bariatric Surgery. (2021, August 6). Retrieved June 13, 2022, from https://asmbs.org/resources/metabolic-and-bariatric-surgery
  6. Arterburn, D. E., Olsen, M. K., Smith, V. A., Livingston, E. H., Van Scoyoc, L., Yancy, W. S., Eid, G., Weidenbacher, H., & Maciejewski, M. L. (2015). Association between bariatric surgery and long-term survival. JAMA, 313(1), 62. https://doi.org/10.1001/jama.2014.16968

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