Is Obesity a Disease

Is Obesity a Disease

The National Institutes of Health (NIH) recognized obesity as a disease in 1998; the Obesity Society did so in 2008. However, it was not until 2013 that the American Medical Association (AMA), considered the most influential medical association in the United States, finally declared that obesity is a complex and chronic (long-term) disease. (1, 2)

However, the AMA decision was controversial, as the public was concerned that putting a label on obesity as a disease could have a negative impact on how people with obesity look at themselves and how they are treated by society.

Furthermore, people were concerned that recognizing obesity as a disease may implicate shifting the emphasis from prevention efforts toward treatment with medications or surgery.

Nevertheless, the AMA and other medical organizations supporting this decision stated that obesity and its associated health problems (comorbidities) had become a leading public health problem.

Therefore, the purpose of recognizing obesity as a complex disease was to eliminate its stigma and shame. Additionally, improving the research efforts into the causes of obesity would eventually lead to a better understanding of the disease and the ways how it can be successfully treated.

Lastly, considering obesity as a disease would ultimately result in better financial support for treatment, insurance coverage, and reimbursement practices for people suffering from this condition. (1, 2)

What is Obesity

Obesity is defined as an excessive buildup of fat in the body, which may ultimately raise the likelihood of adverse health effects and increase the risk of premature death (mortality).

In adults, obesity can be diagnosed using the Body Mass Index (BMI) method, a widespread and simple calculation done by dividing the body mass (weight) in kilograms by the square of the body height in meters and represented in kg/m2.

According to the World Health Organization (WHO), a person meets the criteria for obesity when their BMI is greater than or equal to 30 kg/m2.

For instance, a person who weighs 70 kilograms and has a height of 1.70 meters has a BMI of 24.22 and, therefore, is within a normal weight range (70 kg / 1.70 m2 = 70 / 2.89 = 24.22 kg/m2).

Here is the complete WHO chart used to assess an individual’s nutritional status based on BMI calculation: (3)

BMINutritional Status
Below 18.5 kg/m2Underweight
18.5 to 24.9 kg/m2Normal weight
25.0 to 29.9 kg/m2Overweight
30 to 34.9 kg/m2Obesity class I
35.0 to 39.9 kg/m2Obesity class II
40 kg/m2 and AboveObesity class III (morbid obesity

Is an Altered BMI a Sign of Disease

The BMI indicates the risk for some diseases. The higher the BMI, the more risk a person has of developing obesity-related diseases and premature death.

However, even though BMI is readily available and is the most common method used to diagnose obesity, it is not ideal in all cases, as it does not account for variations in body composition. For instance, a weightlifter may have a higher-than-normal BMI due to a higher percentage of muscle mass, not fat.

This is why other methods can also be used to measure body composition. These include:

  • Skin fold thickness
  • Waist circumference
  • Waist-to-height ratio
  • Waist-to-hip ratio
  • Bioelectrical impedance
  • Densitometry
  • Dual-energy x-ray absorptiometry

Nevertheless, since the tools and techniques required to take these measures are unavailable in all settings, BMI continues to be the most used measurement to diagnose obesity worldwide. (4)

Is BMI Reliable in Kids?

In children and adolescents aged from 0 to 19 years, obesity is also diagnosed using the BMI method. However, due to the high variability between weight and height in individuals of the opposite sex and even in individuals of the same sex but different ages, the BMI in this population is then compared with z-scores or percentiles.

So, during childhood and adolescence, age-specific and gender-specific charts are used to evaluate whether a child or adolescent is within the expected weight and height range.

Obesity is a BMI greater than or equal to the 95th percentile for children and adolescents of the same age and sex. In comparison, severe obesity is defined as a BMI greater than or equal to 120% above the 95th percentile. (5)

Why Is Obesity Considered a Disease

In the past few years, it has been established that obesity involves a wide variety of complex factors involving a combination of behavioral, environmental, and genetic contributors, leading to a long-term imbalance between caloric intake and energy expenditure. (2, 6-8)

Therefore, recognizing obesity as a disease that does not depend only on a person’s behavior (namely having poor dietary choices and lack of physical exercise) can help shift the stigma around people, with obesity being the only culprit of their condition.

Also, it has been determined that some obese people are metabolically healthy, and some normal-weight individuals are metabolically unhealthy. (9-10)

Body Shape and Risk of Obesity

What is more, people with obesity may even have different body shapes. For instance, some individuals can have an apple-shaped body (also called central obesity or visceral obesity). In these people, fat distribution is concentrated primarily in the middle of the body.

In contrast, other people may have a pear-shaped body (also known as peripheral obesity), in which fat distribution is predominantly located in the lower half of the body, particularly in the glutes and thighs.

This distribution of body fat gains relevance because people with an apple-shaped body are more likely to experience metabolic issues than people with a pear-shaped body. (11)

The Consequences of Obesity

In any case, obesity has been shown to hurt most bodily systems, including the kidneys, liver, joints, arteries, heart, and reproductive organs, as well as to increase the risk for a wide range of health problems, such as the following: (12-15)

  • High blood sugar (type 2 diabetes)
  • Heart issues
  • High blood pressure (hypertension)
  • Stroke
  • High level of fats in the blood (hyperlipidemia)
  • Fatty liver
  • Gastrointestinal issues
  • Cancer
  • Arthritis
  • Weakened immune system
  • Hormonal imbalances
  • Breathing problems
  • Sleep disorders

Therefore, when a person is obese, their quality of life will be diminished, and the risk of premature death caused by any of the conditions mentioned above will also be increased.

How Common is Obesity

The World Health Organization (WHO) has released a report stating that more than 1 billion individuals worldwide suffer from obesity, of which 650 million are adults, 340 million are adolescents, and 39 million are children. (13)

According to data from the National Health and Nutrition Examination Survey (NHANES), it was determined that by 2017-2018 in the United States alone, approximately 1 in 5 children and around 2 in 5 adults suffered from obesity, while 1 in 16 children and 1 in 11 adults were diagnosed with severe obesity. (16, 17)

What Factors Contribute To Developing Obesity

The rate of obesity has increased during the last decades, and one of the major contributors to this tendency appears to be environmental factors, such as: (18, 19)

  • The elevated cost of highly nutritional foods (like lean meats, fish, vegetables, and fruits).
  • The low cost of calorie-dense foods with little nutritional value, like processed foods (packaged snacks, deli meats, sugary beverages, pastries, canned or instant products, among others).
  • Large portion sizes.
  • The excessive marketing of unhealthy foods.
  • Food insecurity.
  • Leading a sedentary lifestyle.

However, although the environmental factors mentioned above negatively affect weight management and healthy food choices, many other factors also appear to contribute to this increase in obesity rate, including:

  • Living in a high-stress environment
  • Sleep deprivation
  • Gut microbiota alteration

Endocrine disruptors have been recognized in the last decades as another contributing factor to obesity. These substances and compounds alter the body’s normal hormonal (endocrine) balance. The most commonly known endocrine disruptors are bisphenol A (BPA) and phthalates: (20, 21)

  • Bisphenol A: This substance is frequently used in producing polycarbonate plastics and epoxy resins. BPA can be found in everyday items like toys and food packaging. (22)
  • Phthalates: The primary use of these compounds is as liquid plasticizers; therefore, it is usual to find them in various commonly used items such as fragrances, cosmetics, nail polish, shampoo, aftershave lotion, and even toys. (22)

If Obesity is a Disease, Can It Be Treated

Obesity can and must be treated; however, to successfully maintain a healthy weight long-term, a person must receive nutritional education, implement healthy dietary choices, engage in regular physical activity, and have psychological support.

Studies have demonstrated that losing only around 5% of excess body weight can positively impact several bodily systems, including lower blood pressure and lower glucose (blood sugar) levels, as well as improvement of other biomarkers linked to an increased risk of heart disease. (23, 24)

Dietary Changes

Individualized, sustainable dietary changes over time continue to be the gold-standard approach to treating obesity.

The main goal is to improve food’s nutritional quality while limiting excessive energy intake, thus achieving an adequate energy balance. (24, 25)

According to the US Food and Nutrition Board of the Institute of Medicine, an adult’s healthy diet should have the following distribution of each macronutrient: (26)

  • Carbohydrates: around 45 to 65% of daily nutrient intake
  • Fats: from 20 to 35% of daily nutrient intake
  • Proteins: at least 10% and up to 35% of daily nutrient intake

Nevertheless, the average Western diet is very high in refined carbohydrates and polyunsaturated fatty acids that promote inflammation and weight gain. (27)

To achieve a constant reduction in energy intake, a wide variety of dietary options based on adjusting the distribution of these macronutrients are available, including

  • The low-fat diet,
  • The low-carbohydrate and high-fat diet,
  • The low-carbohydrate and high-protein diet, and
  • The high-protein diet.

Additionally, in recent years intermittent fasting has also gained popularity in restricting excessive energy intake. (28-30)


Besides dietary modifications, the use of adjuvant medications may also be necessary to successfully treat obesity if satisfactory weight loss has not been achieved after one year. Liraglutide, semaglutide, orlistat, bupropion, and bupropion/naltrexone are a few examples of these medications. (31-33)

Surgical Treatment

Metabolic and bariatric surgery may be considered to aid in the treatment of obesity in selected cases, such as: (34)

  • When a person has a BMI greater than 35 kg/m², regardless of whether weight-related health issues are present or not.
  • If a person has metabolic disease and a BMI of 30 to 34.9 kg/m².
  • In cases when an individual has a BMI of 30 to 34.9 kg/m² and one or more of the following circumstances:
  • ○ Adequate dietary changes were unsuccessful in achieving significant weight loss.
  • ○ People who could not maintain their weight loss over time.
  • ○ Individuals who did not experience improvement in weight-related health issues.

What About Obesity Treatment In Children And Adolescents

In January 2023, the American Academy of Pediatrics (AAP) released a guideline on how to assess and treat children and adolescents with obesity, taking into account several individualized factors, including the children:

  • Overall health state
  • Socioeconomic status
  • Support network and family
  • Community context

In this guideline, experts recommend early approaches focused on behavioral and lifestyle changes, using drugs or bariatric surgery when indicated. (5)

How To Prevent Obesity

Obesity can and should be prevented to improve the general population’s life expectancy and quality of life. In addition to having a balanced and nutritious diet, reducing the intake of processed foods and sugary drinks, and engaging in regular exercise, obesity can be prevented by the following strategies: (2-4,35,36)

Raising awareness of obesity as a disease instead of a choice

Education is a powerful and effective tool in the fight against obesity. People’s everyday decisions regarding their dietary choices and other healthy habits may be significantly impacted if they are properly informed about the health risks of this disease.

In this regard, educational campaigns in schools, workplaces, and communities can be useful in encouraging people to adopt healthy lifestyles.

Recognizing and dealing with emotional factors

As previously mentioned in this article, obesity is multifactorial, and psychological aspects are one of the main factors affecting how people use unhealthy eating habits to cope with stress, depression, and anxiety.

Therefore, stress management techniques, such as mindfulness, meditation, or counseling services, should be encouraged from a young age.

Promoting healthy eating environments

The marketing of unhealthy foods has a significant impact on how people, especially children, and adolescents, make choices about what and how much to eat.

Therefore, to encourage the intake of highly nutritious foods over unhealthy and processed foods, it is crucial to promote healthy eating environments in schools and communities.

Encouraging all family members to participate:

Efforts made towards preventing obesity are much more effective when every family member invests in adopting healthy lifestyle habits, especially when going grocery shopping, cooking, and eating together as a family.

Engaging in some fun sport or physical activity like hiking or biking that can be done and enjoyed by all family members is also a good way to promote exercise and an active lifestyle.


Obesity is considered a disease because it can produce several consequences to the body, including diabetes, heart disease, blood lipid disorders, and sleeping disorders, among others. Efforts are being made worldwide to raise awareness among people from all walks of life to understand this delicate issue.

Consultation with a physician should be made to prevent the complications of obesity and live a happy and healthy life.

See Also

Obesity Clinical Trials

Grants for Obesity Prevention Programs

What is the Safest Weight Loss Surgery?

Obesity Rate in America (by State)

What is Least Invasive Weight Loss Surgery?

Current Version
June 29, 2023
Written By
Krystie Linares, MD
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