What is obesity? A chronic disease, explained, and how LUX can help
Obesity is a medical condition shaped by biology, not a failure of willpower. Here is what that means, why diets alone so often fall short, and what effective, modern treatment looks like.
For decades, weight was treated as a simple equation: eat less, move more, and try harder if it isn't working. Millions of people did exactly that and still struggled, and many came away believing the problem was them. Medicine now understands that picture was incomplete. Obesity is a chronic disease with genetic, hormonal and metabolic roots, and it responds best to care that treats it that way.
How obesity is defined
In June 2013 the American Medical Association formally recognized obesity as a disease. The Obesity Medicine Association (OMA), whose clinical guidance LUX follows, describes obesity as a chronic, relapsing, multi-factorial, neurobehavioral disease in which an increase in body fat leads to fat-tissue dysfunction and to metabolic, biomechanical and psychosocial health consequences.
Each part of that definition matters:
- Chronic: it is long-term and usually needs ongoing management, much like high blood pressure or type 2 diabetes.
- Relapsing: weight tends to return when treatment stops, because the body actively defends its previous weight.
- Multi-factorial: there is no single cause. Genes, hormones, medications, sleep, stress and environment all play a part.
- Neurobehavioral: the brain's appetite and reward systems are central to how hunger, fullness and cravings work.
For adults, obesity is screened with body mass index (BMI): a BMI of 25 to 29.9 is classified as overweight, 30 or higher as obesity, and 40 or higher as severe obesity. BMI is a useful starting point, but it doesn't measure body fat directly or show where fat is stored. A medical evaluation also looks at waist size, body composition, lab work and related health conditions.
How common is obesity?
Obesity is one of the most common chronic conditions in the country. According to the CDC's National Health and Nutrition Examination Survey, 40.3% of U.S. adults had obesity between August 2021 and August 2023, and 9.4% had severe obesity. It was most common among adults aged 40 to 59, at 46.4%.
In other words, if you are living with obesity, you are in the company of roughly four in ten American adults. It is a medical condition, and it deserves medical care.
What causes obesity?
Obesity develops when several factors push the body's energy regulation toward storing more fat. Common contributors include:
- Genetics: genes account for a large share of a person's risk. A genetic tendency doesn't make obesity inevitable, but it changes how hard the body pushes back.
- Hormones and metabolism: hormones that control hunger, fullness and fat storage, along with insulin resistance, strongly influence weight.
- Nutrition quality: not all calories act the same. Highly processed foods and refined carbohydrates can drive hunger and fat storage.
- Medications: some common prescriptions, including certain antidepressants, steroids and diabetes medications, can cause weight gain.
- Sleep: too little sleep, irregular sleep and sleep apnea disrupt the hormones that regulate appetite.
- Stress and emotional health: chronic stress affects hormones and eating patterns.
- Environment: work schedules, food access, culture and family routines all shape daily habits.
Why willpower isn't the answer
When you lose weight through dieting alone, your body responds as if food were scarce. Hunger signals tend to rise, fullness signals tend to fall, and the body can burn less energy than before. These changes make it hard to keep weight off, and they explain why so many people regain weight despite real effort.
Weight management is a medical conversation, not a willpower one.
This is why the most effective treatment works with the body's biology rather than against it, and why ongoing support matters as much as the starting plan.
Health conditions linked to obesity
Obesity raises the risk of many other conditions, which is why treating it early is a form of preventative care. Linked conditions include:
- Type 2 diabetes and prediabetes
- High blood pressure
- Heart disease and stroke
- High cholesterol
- Sleep apnea
- Fatty liver disease
- Joint pain and osteoarthritis
- Certain cancers
Even modest, sustained weight loss can improve blood sugar, blood pressure and cholesterol for many people. Your provider can help you set goals that matter for your health, not only for the scale.
How obesity is treated today
The OMA describes four pillars of obesity treatment: nutrition, physical activity, behavior and medication. LUX adds a fifth, sleep and recovery, because of how strongly sleep affects appetite and metabolism. Most people do best with a combination tailored to them.
1. Medical interventions
FDA-approved medications have changed what's possible in obesity care. GLP-1 receptor agonists mimic gut hormones that help regulate appetite, slow stomach emptying and improve blood-sugar control. Semaglutide was approved by the FDA for chronic weight management in June 2021, and tirzepatide, which acts on both the GLP-1 and GIP receptors, in November 2023. These medications are indicated for adults with a BMI of 30 or higher, or 27 or higher with a weight-related condition, alongside diet and activity changes.
Other options include phentermine, an appetite suppressant approved for short-term use, and, for some patients, peptide therapies considered as part of a broader plan. Every medication has benefits, side effects and people it isn't right for, which is why a medical evaluation always comes first.
2. Nutrition therapy
Sustainable eating patterns that fit real life work better than strict restriction. The focus is on nourishment, protein and food quality, especially while taking medications that reduce appetite.
3. Physical activity and movement
Movement plans should start where you are. Strength training is especially valuable because it helps preserve muscle as you lose weight.
4. Behavioral and emotional health
Understanding triggers, building small repeatable habits and addressing emotional eating help the other pillars last.
5. Sleep and recovery
Consistent, restorative sleep and stress management support the hormones that regulate hunger, fullness and metabolism.
How LUX can help
LUX Medical Weight Loss and Wellness in Oconomowoc was built around this modern understanding of obesity. Our philosophy is simple: care should be medically guided, individually built and confidently human.
- A free 15-minute consultation to talk through your goals and history, with no obligation.
- A medical evaluation by Nicole Crivello, MSN, APNP, FNP-C, who personally evaluates, prescribes and monitors every treatment plan.
- A plan built on all five pillars: medical interventions when appropriate, nutrition, movement, behavioral support, and sleep and recovery.
- Ongoing monitoring and shared decision-making as your body and goals change.
- Non-invasive body contouring to support body confidence alongside your progress.
- Transparent cash pricing with flexible financing through CareCredit.
If you have tried to manage your weight on your own and felt like you were fighting your own body, you're not imagining it. You don't have to do it alone.
Book your free 15-minute consultation
Frequently asked questions
Is obesity a disease?
Yes. The American Medical Association recognized obesity as a disease in June 2013, and the Obesity Medicine Association defines it as a chronic, relapsing, multi-factorial, neurobehavioral disease.
What BMI is considered obesity?
For adults, a body mass index (BMI) of 30 or higher is classified as obesity, and 40 or higher as severe obesity. BMI is a screening tool; a provider also looks at body composition, waist size and overall health.
How common is obesity in the United States?
According to CDC data from August 2021 to August 2023, 40.3% of U.S. adults had obesity and 9.4% had severe obesity.
Can obesity be treated with medication?
Yes. FDA-approved medications for chronic weight management, including GLP-1-based medications such as semaglutide and tirzepatide, are used alongside nutrition, activity and behavioral changes for eligible adults, after a medical evaluation.
Sources
- Obesity Medicine Association, "What Is Obesity?"
- Obesity Medicine Association, "AMA Adopts Policy, Recognizes Obesity as a Disease" (June 2013)
- CDC National Center for Health Statistics, "Obesity and Severe Obesity Prevalence in Adults: United States, August 2021–August 2023"
- Healio, "FDA approves once-weekly semaglutide for weight loss" (June 4, 2021)
- U.S. FDA, "FDA Approves New Medication for Chronic Weight Management" (tirzepatide, November 8, 2023)
This article is for general education and is not medical advice. Talk with a qualified provider about your own health, and about whether any treatment is right for you. Prescription medications are available only after a medical evaluation and are not appropriate for everyone. Individual results vary.