Is obesity a chronic disease?

Yes, obesity is a chronic disease that is defined by the World Health Organization (WHO) as abnormal or excessive fat accumulation that may impair health. The American Association of Clinical Endocrinologists (AACE) and the American College of Endocrinology (ACE) have published practice guidelines for treating patients with obesity.

How many people in the US have obesity?

Obesity is one of the most prevalent diseases in the US, affecting approximately 108 million adults. By comparison, there are 78 million adults in the US who could benefit from cholesterol medicine, and about 108 million adults in the US have high blood pressure.

What factors contribute to obesity?

The main contributing factors of obesity can be broken into three categories: societal, environmental, and genetic. Societal and environmental factors include changes in food production and availability, decreases in energy expenditure due to more sedentary lifestyles, socioeconomic status, cultural influences, and societal changes such as overeating and reduced physical activity. Genetic factors may determine the extent to which these societal and environmental factors will impact a patient’s weight.

What physiological mechanisms contribute to obesity?

Weight loss from reduced-caloric intake triggers a physiological process called metabolic adaptation. Weight loss causes the body to react by slowing the metabolism and altering appetite-regulating hormones, which can make long-term weight management difficult.

Does obesity increase the risk of mortality?

Yes, increased BMI results in a higher risk of mortality. For every 5 kg/m2 BMI increment above the range of 22.5-25 kg/m2, there is a 30% increase in overall mortality.

How does obesity impact patients aside from their physical health?

Patients with obesity can face a multitude of challenges, both socially and psychologically, including self-esteem issues as well as weight biases in both social and workplace situations.

What types of patients could benefit from pharmacological treatments for weight loss?

Patients with overweight or obesity who have tried lifestyle changes but can’t reach a healthier weight, are having difficulty with weight management, have a BMI of ≥27 kg/m2 and a weight-related comorbidity, or have a BMI that is >30 kg/m2 may benefit from pharmacological treatments.

Is there a strategy I should use when talking with patients about weight management?

The 5As model is recommended: ASK for permission to discuss weight, ASSESS obesity class and stage, ADVISE on obesity risks, AGREE on realistic weight-loss expectations, and ASSIST by providing education, resources, and support.

What are some conversation starters I can use when discussing weight management with patients?

Start with a discussion on weight history, including changes in weight over time, factors in weight changes, past weight-management efforts, and current habits.

What percent weight loss should most patients aim for?

A modest weight loss of 5% or more can have a clinically meaningful impact, improving cardiovascular risk factors such as glycemic control, blood pressure, HDL cholesterol, and triglycerides. Higher levels of weight loss can be associated with greater improvements in some comorbidities.

How can I work with my patients to set and achieve their weight-management goals?

Set long-term goals for patients and create a plan to help them achieve them using SMART goals: SPECIFIC, MEASURABLE, ACHIEVABLE, RELEVANT, and TIMELY.

Where can I find more tools to help me learn how to improve discussions with my patients?

The Obesity Treatment Modules Educational Series provides practical tools designed for HCPs and their office staff. It includes strategies and tips for diagnosing and discussing obesity with patients.

How can advocacy help support my patients with obesity?

Partnering with patients to develop comprehensive and individualized approaches to weight loss and weight management can make a significant impact. Advocacy helps fill gaps in health care that are keeping patients from successful weight loss.

How can I get more involved with patient advocacy for obesity?

Contact the Obesity Care Advocacy Network (OCAN) to advocate for individual patients, reach out to legislators, and understand current policy.

What is the relationship between COVID-19 and obesity?

Obesity puts individuals at a higher risk of severe illness with COVID-19. It is important to discuss weight-management care with patients who have obesity.

Why is it important to address weight-loss strategies in adolescents with obesity?

Obesity in adolescence has increased significantly, and many weight-related conditions seen in adults are now common in adolescents. Ongoing monitoring and treatment are required, including lifestyle modification, pharmacotherapy, or surgical intervention.

How do cultural factors impact obesity?

Cultural factors can influence weight goals, acceptance of body images, and the willingness to seek medical help. It's important to consider these factors when setting weight-management goals with patients.

If there is a connection between obesity and many comorbidities, will losing weight improve those conditions?

Obesity is associated with numerous comorbidities, including obstructive sleep apnea, type 2 diabetes, and hypertension. Studies show that even a weight loss of as little as 5% can help improve many of these comorbidities.

Long term considerations | Rethink Obesity

Learn about obesity and associated risk factors

Get the facts about adolescent obesity

LONG-TERM CONSIDERATIONS IN OBESITY MANAGEMENT

While a 5%–10% weight loss is clinically meaningful, effective obesity management encompasses more than weight reduction¹

As patients lose weight, clinicians should consider potential long-term changes that may affect overall health and function, including²:

Fatigue
Fatigue may occur during weight loss, particularly when consuming very low-calorie diets.²

Gallstones
Rapid or substantial weight loss increases the risk of gallstone formation because of changes in bile composition and gallbladder emptying.²

Hair loss
Temporary hair shedding can occur following significant or rapid weight loss, often related to consuming very low-calorie diets.¹

Muscle and bone loss
Weight loss of any kind is a known factor for loss in bone density and lean muscle mass, potentially affecting strength and fracture risk if not appropriately managed.^1,3,4

Some effects of weight loss, such as fatigue, hair loss, or gallstones, may be more readily noticeable to patients. Bone loss, however, can occur gradually and may be less apparent over time, presenting a unique challenge for long-term health.^2–4

Bone loss risk is not the same for every patient^5,6

Although all patients lose weight differently, factors such as age, sex, and baseline
bone health can substantially influence the risk of bone loss.^4–7

Overweight post-menopausal women

Risk of bone loss increases due to declining estrogen levels regardless of weight reduction, so even modest weight loss may further reduce bone mineral density by 1%-4%.^8*

*Data from a 6‑month prospective, controlled dietary intervention study in 66 postmenopausal women with overweight, randomized to either a weight‑loss program (either 1 g/day or 1.7 g/day of calcium), or a weight‑maintenance control (1 g/day of calcium). Study evaluated the effects of weight loss and calcium intake on bone health.⁸

Men with obesity

Starting in their 30s, men may begin to experience gradual declines in bone mass that accumulate over time.⁹

During weight loss, men with obesity can experience increased bone resorption⁷

Older adults with obesity

Excessive weight loss, particularly in older adults with obesity, may contribute to sarcopenia and reduced bone mineral density.^1,7

Improving overall health through weight management remains critical for all patients with obesity.¹

Obesity management goals are shifting to optimize quality weight loss, more fat mass loss vs lean mass loss¹⁰

Bone is living tissue that is continuously broken down and rebuilt. Weight loss can influence this natural process, making bone health an important consideration when managing patients with obesity.^7,11

Looking beyond weight alone may support more informed conversations about obesity.¹

Learn more

Your questions answered about obesity, bone health, and weight loss

Bone health

Quality weight loss

How does weight loss impact bone density?

Significant weight loss can result in bone density loss, as weight loss affects the entire body, not just fat mass.¹²

Are women more susceptible than men to bone loss?

Yes, especially postmenopausal and premenopausal women, who are more susceptible to bone loss than men due to declining estrogen levels.^5,6

Can men get osteoporosis?

Yes, though less common than in women, men can also experience osteoporosis, especially after the age of 50.¹³

Why is preventing loss of bone density important during weight loss?

Preventing bone loss is critical for avoiding fragile bones that put a person at high risk for fractures, which can lead to loss of mobility and long-term disability.^3,13

What is quality weight loss?

Quality weight loss can be defined as losing a higher proportion of fat mass vs skeletal muscle mass to maintain musculoskeletal integrity.¹⁰

What is the latest guidance on quality weight loss?

Quality weight loss is a growing topic of discussion in the scientific community. Some loss of lean mass is a normal consequence of weight loss; however, ideally, most of the weight lost should come from fat mass rather than lean mass.¹⁰

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References

1. Nadolsky K, Garvey WT, Agarwal M, et al. American Association of Clinical Endocrinology consensus statement: algorithm for the evaluation and treatment of adults with obesity/adiposity-based chronic disease - 2025 update. Endocr Pract. 2025;31(11):1351-1394.

2. Apovian CM, Aronne L, Barenbaum SR. Clinical Management of Obesity. 3rd ed. Professional Communications, Inc.; 2024.  

3. Villareal DT, Fontana L, Weiss EP, et al. Bone mineral density response to caloric restriction-induced weight loss or exercise-induced weight loss: a randomized controlled trial. Arch Intern Med. 2006;166(22):2502-2510.

4. Ensrud KE, Ewing SK, Stone KL, et al. Intentional and unintentional weight loss increase bone loss and hip fracture risk in older women. J Am Geriatr Soc. 2003;51(12):1740-1747.    

5. Hannan MT, Felson DT, Anderson JJ. Bone mineral density in elderly men and women: results from the Framingham osteoporosis study. J Bone Miner Res. 1992;7(5):547-553.    

6. Hannan MT, Felson DT, Dawson-Hughes B, et al. Risk factors for longitudinal bone loss in elderly men and women: the Framingham osteoporosis study. J Bone Miner Res. 2000;15(4):710-720.    

7. Hyldstrup L, Andersen T, McNair P, Breum L, Transbøl I. Bone metabolism in obesity: changes related to severe overweight and dietary weight reduction. Acta Endocrinol (Copenh). 1993;129(5):393-398.

8. Riedt CS, Cifuentes M, Stahl T, Chowdhury HA, Schlussel Y, Shapses SA. Overweight postmenopausal women lose bone with moderate weight reduction and 1 g/day calcium intake. J Bone Miner Res. 2005;20(3):455-463.    

9. Riggs BL, Melton LJ, Robb RA, et al. A population-based assessment of rates of bone loss at multiple skeletal sites: evidence for substantial trabecular bone loss in young adult women and men. J Bone Miner Res. 2008;23(2):205-214.    

10. Harper ME, Dent RRM, McPherson R. High-quality weight loss in obesity: importance of skeletal muscle. Diabetes. 2025;74(12):2191-2198.    

11. National Library of Medicine. Bone density. MedlinePlus. Published 2020. Accessed August 1, 2026. https://medlineplus.gov/bonedensity.html  

12. Armamento-Villareal R, Aguirre L, Waters DL, Napoli N, Qualls C, Villareal DT. Effect of aerobic or resistance exercise, or both, on bone mineral density and bone metabolism in obese older adults while dieting: a randomized controlled trial. J Bone Miner Res. 2020;35(3):430-439.    

13. US Preventive Services Task Force. Screening for osteoporosis to prevent fractures: US Preventive Services Task Force recommendation statement. JAMA. 2025;333(6):498-508.