Bariatric Surgery News Stories

Body Mass Index: Explained

More than two-thirds of adults in the United States are overweight, and over one-third are obese, according to data revealed by the Centers for Disease Control and Prevention.

Washington University bariatric surgeons use measures such as body mass index (BMI) calculations and other screening indicators to determine whether their prospective patients are eligible for weight loss surgery. To understand why this tool is used, one must first understand what BMI is.

What is BMI?

Body mass index (BMI) is a calculation that helps determine a healthy body weight based on your height. According to the Centers for Disease Control and Prevention, BMI is an inexpensive screening tool used to determine weight categories that may lead to health problems.

BMI can be calculated by dividing a person’s weight in pounds by the square of height in inches and multiplying by a conversion factor of 703. For example, if a patient is 5’5” (65”) and weighs 180 lbs., this is the formula to calculate their BMI:

[180 ÷ (65)2] x 703 = 30.0

“Our team makes it very simple for patients who may be interested in weight loss surgery to determine if they may be eligible,” says Shaina Eckhouse, MD, a Washington University weight loss surgeon. “Patients can use our integrated BMI Calculator tool on our website to determine their BMI based on their weight and height in both kilograms and pounds and register for a weight loss surgery seminar all on one simple step.”

How is BMI interpreted in adults?

For adults 20 years and older, BMI is interpreted using standard weight status categories such as underweight, healthy weight, overweight, and obese. These categories are the same for men and women of all body type and ages.

Two column, six row table describing the World Health Organization's BMI criteria.
BMI criteria.

The World Health Organization has established a different obesity classification for Asian and Pacific Islanders patients. This criteria is:

BMIWeight Status
Below 18.5Underweight
18.5 – 22.9Healthy Weight
23.0 – 24.9Overweight
25 +Obesity


For children and teens, BMI is calculated using the same formula but interpreted based on sex due to the amount of body fat changes and differences between girls and boys. Certain BMI-for-age growth charts help determine these differences and show BMI as a percentile ranking.

People who are very muscular, such as body builders, may have a higher BMI but are in good health. A slightly higher BMI in elderly patients also may indicate protection against conditions like osteoporosis. Health care providers should also take other measures, such as a patient’s waist circumference and waist-to-hip ratio, into consideration when determining whether a patient is overweight for their body type.

“Your BMI alone cannot predict your health risk,” says Dr. Eckhouse. “However, obesity puts strain on your heart and can lead to serious health issues like heart disease, high blood pressure, sleep apnea, diabetes, fatty liver disease, and other conditions.”

What are the requirements for weight loss surgery?

There are distinct requirements that a patient must meet to qualify for weight loss surgery. Candidates must:

  • Be at least 15 years old
  • Have a BMI of 40 or greater, or:
    • A BMI of 35 or greater with one or more of the following conditions:
      • Diabetes
      • High blood pressure
      • Sleep apnea
  • Have attempted a structured dietary weight loss program.

All patients who are considering weight loss surgery must attend a weight loss surgery seminar and undergo evaluation by a behavioral therapist, dietician and physical therapist. Once the patient is approved, Washington University bariatric surgeons will help them take the next step in their weight loss journey and identify the best course of treatment for each patient.

Dieticians, behavioral therapists and physical therapists in the weight loss surgery program play a critical role in optimizing a patient’s success after surgery. Once accepted into the program, patients will receive focused, one-on-one counselling with registered dieticians to help them prepare for success after surgery and for the rest of their lives. Behavioral therapists will assist patients as weight loss treatments changes their relationship with food, and specialized psychiatrists are also available to support patients who may struggle with eating or weight pattern conditions, such as binge eating disorders. Physical therapists can provide support and guidance in exercise and treatment for conditions that may interfere with a patient’s ability to exercise.

“From the moment a prospective patient attends one of our seminars and feels empowered to take the next step in their weight loss journey, our entire team works together to ensure we are providing the resources and support they need to thrive,” says Dr. Eckhouse. “We look forward to helping you find your pathway to success and walking you through this life-changing journey.”

I’m not a candidate for weight loss surgery. Are there other options available?

There are always options to help set patients on the right path to restoring their health and managing their obesity. There are several non-surgical (endoscopic) weight loss therapies to help a wide range of patients lose weight. These therapies include intragastric balloon, endoscopic sleeve gastroplasty, and endoscopic gastric outlet repair.

In June 2022, Michelle Cusumano, NP, will begin providing medical management of obesity for patients best suited for non-medical treatments for obesity and will be supported by Washington University dieticians.

Who is the Bariatric Surgery Team?

J. Chris Eagon, MD

Associate Professor of Surgery
Section of Minimally Invasive Surgery
Division of General Surgery

Shaina R. Eckhouse, MD

Associate Professor of Surgery

Section of Minimally Invasive Surgery
Division of General Surgery
Associate Director, Washington University Weight Loss Surgery
Surgical Liaison
Surgical Liaison, BJH Perioperative Services Leadership Team

Francesca M. Dimou, MD, MS

Assistant Professor of Surgery

Section of Minimally Invasive Surgery
Division of General Surgery

Washington University bariatric surgeons J. Chris Eagon, MD, Shaina Eckhouse, MD, and Francesca Dimou, MD, MS, offer life-changing obesity treatment through minimally invasive laparoscopic procedures, including gastric bypass and sleeve gastrectomy. The Bariatric Surgery Team consults with patients and performs procedures at the Center for Advanced Medicine and Barnes-Jewish West County Hospital.

I am a candidate for weight loss surgery and I am ready to take the next step. What do I do?

Registering for a weight loss surgery seminar is simple—Prospective patients can visit the team’s website and select a virtual time slot with a Washington University bariatric surgeon that works best for their schedule or complete this online form to hear more about the online seminars from our program coordinators. For additional information, please call (314) 454-7224.