A Guide to Understanding the Severity of Obesity
Health ConditionsObesity

A Guide to Understanding the Severity of Obesity

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Published on March 9, 2026
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M ore than 2 in 5 adults in the United States have obesity, a complex, chronic health condition that can be difficult to treat over the long term. But all too often, the condition is reduced to a single number or framed as a personal failure.

This guide is designed to help you understand how obesity is defined, what “severity” really means, and why it matters for your overall health. Whether you’re navigating a new diagnosis or struggling to manage the condition, this information can help you work with your care team to make the best decisions for your health.

2 in 5
More than two in five adults in the United States have obesity
SOURCE: Centers for Disease Control and Prevention

How Is Obesity Diagnosed?

Obesity is a chronic condition in which excess body fat builds up over time, increasing the risk of serious health problems, such as heart disease, diabetes, and certain cancers. Obesity is diagnosed using body mass index (BMI), a tool that assesses whether the weight you’re at may increase your risk of health problems. It’s calculated by dividing your weight in kilograms by the square of your height in meters. In adults, a BMI of 30 or higher is considered obesity.

But the tool isn’t perfect. Although simple and efficient, “BMI does not distinguish fat from muscle or reflect fat distribution, which is relevant metabolically,” says Priya Jaisinghani, MD, an endocrinologist who specializes in obesity medicine and diabetes at NYU Langone Health in New York City.

Because of these limitations, doctors use BMI as a starting point only. “We also look at waist size, waist-to-height ratio, and waist-to-hip ratio,” says Sara Velayati, MD, an obesity medicine specialist at Montefiore Einstein in the Bronx, New York.

Doctors can also order lab work and other tests to look for “silent” signs of obesity’s effects on organs and other parts of the body. These signs can be detectable long before symptoms appear, says Dr. Velayati.

These tests include:

Diagnostic Tests

In addition, doctors will evaluate how the disease affects your energy levels, mental health, mobility, and quality of life. “This personalized approach ensures care is based on your actual health and function, not just a number,” says Velayati.

Health Risks of Obesity

Over time, excess body fat — especially around the abdomen — releases hormones and inflammatory signals that disrupt normal bodily functions. 

“The heart works harder, so blood pressure rises, arteries stiffen, insulin becomes less effective, and ‘bad’ cholesterol and triglycerides rise, while ‘good’ cholesterol falls,” says Velayati. “These changes quietly increase the risk of heart attack, stroke, kidney disease, and nerve damage — often years before symptoms develop.”

By treating obesity in its earlier stages, it’s possible to ward off some of these symptoms, which can help protect your health over the long term.

How Obesity Is Classified

To better understand how weight may affect your long-term health, doctors use three classes of obesity, along with a clinical assessment, to determine the urgency of treatment.

 As BMI rises, the risk of complications usually increases, says Velayati.

Even people with a lower BMI can have serious medical effects, though, says Velayati. So it’s important to take stock of the obesity class your weight falls under and any complications you have.

Quiz: How Much Is Obesity Affecting Your Life?

This self-assessment is designed to help you reflect on how weight may be affecting your health, overall well-being, and quality of life. The results aren’t intended to be a diagnosis, but they can help guide conversations with your healthcare provider.

FIND OUT HOW MUCH OBESITY AFFECTS YOU

Question 1/7

How often do you feel physically limited by your weight?

  • Never
  • Occasionally
  • Often or most days

Talk to Your Doctor

Because obesity is a chronic, progressive disease, the focus of treatment is not just weight loss, but also a meaningful improvement in your health, daily function, and quality of life.

“A comprehensive plan should include nutrition, physical activity, sleep, stress management, behavioral support, and, when indicated, medication or surgery,” says Dr. Jaisinghani. “It’s also important to discuss strategies to preserve muscle, prevent weight regain, and address emotional and psychological factors.”

“Care requires treating the whole person, not just the numbers on the scale,” she adds.

Here are some typical treatment strategies your doctor may recommend, based on your needs.

Your primary care doctor may be able to help you with weight loss efforts, but you may also want to see a certified obesity specialist — a healthcare provider who specializes in treating obesity. You can find lists of these specialists from the Obesity Medicine Association and American Board of Obesity Medicine.

Once you find a healthcare provider you like, consider asking them some of the following questions about the condition and treatment options.

Questions to Ask Your Doctor

  1. What is a reasonable, healthy goal weight for me?
  2. What other health markers (such as blood pressure, blood sugar, and cholesterol) should we track?
  3. Which obesity-related conditions am I most at risk for or do I already have?
  4. What evidence-based treatments can help me reach my goals and prevent further complications?
  5. Once we start treatment, what are realistic milestones for me at three, six, and nine months?
  6. How should I handle weight loss plateaus?
  7. Are there other resources, such as a dietitian, sleep specialist, or therapist, you can recommend to help me stay on track?

Resources We Love

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Adult Obesity Facts. Centers for Disease Control and Prevention. May 14, 2024.
  2. About Body Mass Index (BMI). Centers for Disease Control and Prevention. December 16, 2025.
  3. Vorvick LJ et al. Health Risks of Obesity. MedlinePlus. July 3, 2025.
  4. Purnell JQ. Definitions, Classification, and Epidemiology of Obesity. EndoText. May 4, 2023.
Additional Sources
  • Park NH et al. Comparative Study for Fatigue Prevalence in Subjects With Diseases: A Systematic Review and Meta-Analysis. Scientific Reports. October 7, 2024.
  • Obesity Hypoventilation Syndrome. National Heart, Lung, and Blood Institute. March 24, 2022.
  • Esmaeili N et al. The Relationship Between Obesity and Obstructive Sleep Apnea in Four Community-Based Cohorts: An Individual Participant Data Meta-Analysis of 12,860 Adults. eClinicalMedicine. May 2025.
  • Segal Y et al. Psychological Issues Associated With Obesity. StatPearls. May 2, 2024.
Meet Our Experts
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Adam Gilden, MD, MSCE

Medical Reviewer
Diplomate of American Board of Obesity Medicine Foundation

Adam Gilden, MD, MSCE, is an associate director of the Obesity Medicine Fellowship at University of Colorado School of Medicine and associate director of the Colorado University Medicine Weight Management and Wellness Clinic in Aurora. Dr. Gilden works in a multidisciplinary academic center with other physicians, nurse practitioners, registered dietitians, and a psychologist, and collaborates closely with bariatric surgeons.

Gilden is very involved in education in obesity medicine, lecturing in one of the obesity medicine board review courses and serving as the lead author on the Annals of Internal Medicine article "In the Clinic" on obesity.

He lives in Denver, where he enjoys spending time with family, and playing tennis.

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Susan Jara

Author

Susan Jara is a health communications strategist and writer with more than 15 years of experience transforming complex medical information into clear, accurate, and engaging content for diverse audiences of patients and caregivers. She specializes in patient education, health literacy, and SEO-driven content strategy, with expertise across chronic disease, mental health, addiction, arthritis, autoimmune conditions, and wellness.

Susan holds a bachelor’s degree in journalism and media studies from New York University’s Gallatin School of Individualized Study. Her career includes leadership roles at the Global Healthy Living Foundation and Health Monitor Network, where she developed multichannel health content across web, email, podcasts, video, social media, and print. Susan's work reaches millions of readers each year, and she collaborates with leading healthcare providers, researchers, advocacy groups, and industry partners to create resources that reach millions of readers each year.

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