All About Obesity

What Is Obesity?

Obesity is a biological, preventable, and treatable disease that means a person has too much body fat. There are different factors that can contribute to a person having obesity, including family history and one’s environment. Obesity is not a character flaw, consequence of poor will power or anyone’s fault.

Obesity has traditionally been defined as a body mass index (BMI) of 30 or more. The BMI is a ratio of your weight to height that is not affected by age, gender, or race.

It is important to recognize and treat obesity because having it can put people at risk for many other chronic illnesses, including type 2 diabetes, diseases of the heart and cardiovascular system, some types of cancer, depression, arthritis, disordered breathing, deconditioning and gastrointestinal disorders.

Obesity was officially declared a disease by AACE in 2012, and the American Medical Association adopted this assessment in 2014. While most commonly referred to as obesity, in 2017 AACE experts redefined the disease to Adiposity-Based Chronic Disease, or ABCD. The term focuses on the characteristic pathophysiological effects of excess weight, rather than the weight itself, and offers physicians standardized protocols for weight loss and treatments for obesity-related conditions such as type 2 diabetes, heart disease, stroke, some types of cancers and others.

What Causes Obesity and Who Is at Risk?

Obesity occurs when your body stores too much fat. This can happen when more calories are taken into your body compared to how much your body uses. But it is not that simple – there are different risk factors that are out of our control that can influence this balance. They include:

  • Family inheritance and genes: The genes you receive from your parents can influence how much body fat you store, how you process it and where the fat is distributed. Your genes can even affect your appetite. If your family members have obesity, there is a higher chance that you may develop the disease.
  • Diseases and medications: Sometimes other medical conditions or medications lead to unhealthy weight gain and make the balance of caloric intake to consumption more difficult. If you have Prader-Willi Syndrome, Cushing Syndrome, or arthritis, for example, or are taking antidepressants, you may have a higher risk of developing obesity.
  • Social and economic factors: A person’s social and economic circumstances can affect the risk of developing obesity. The reasons are complex and there are many factors involved, such as lack of access to healthy foods.
  • Age: Even though obesity can occur at any age, the chances that you develop obesity increase as you get older. This is due to changes in the balances of hormones, a less active lifestyle and a reduction in muscle mass.
  • Other factors: Factors can influence your overall health and risk of obesity. These include smoking, lack of sleep and stress, which can negatively contribute to your health.

Speak to your health care provider if you think you may be at risk for obesity. Even if one or more of these factors apply to you, it does not mean you definitely will develop obesity. Together with your health care provider, you can develop a management plan that reduces your risk and aims to keep you healthy.

What Are The Symptoms Of Obesity?

The greatest sign or symptom of obesity is a person’s BMI. A lean or underweight person has a BMI of 18.5 or less. At a BMI of 25, a person is considered to be overweight. The higher the BMI, the higher the health risk. The threshold for obesity is a BMI of 30 or higher. It can be further defined as follows, in increasing order of risk for your health:

  • Class 1 obesity: BMI 30-34.9 kg/m2
  • Class 2 obesity: BMI 35-39.9 kg/m2
  • Class 3 obesity: BMI ≥ 40 kg/m2

The BMI does not directly measure a person’s body fat. There are cases, such as for muscular athletes, where the BMI is in the obesity category, but the person does not have excess body fat. Read more about the BMI index.

How Is Obesity Diagnosed?

A health care provider will use a variety of tools to make a diagnosis. This will begin with an evaluation of a person’s health history, including any past challenges with weight management, exercise habits, eating patterns and medical history. Be honest with your health care professional, as this will impact the diagnosis.

In addition, a number of tests may be conducted:

  • General physical exam that examines your height and vital signs
  • Calculation of your BMI, which is one of the most telling symptoms of obesity. A BMI of 30 or higher is generally considered as obesity
  • Measure of your waist circumference, which can indicate how much fat you have stored around your waist. A high waist circumference can increase the chance of heart disease and diabetes. Specifically, women with a measure of more than 35 inches and men of more than 40 inches fall into higher risk category
  • Blood tests: Your health care provider may want to measure a few different factors such as your cholesterol, liver function and/or fasting glucose (sugar) levels using a blood test

All this information together will help you and your health care provider understand how to approach the disease. Find endocrine care in your area.

What Are the Health Risks Linked to Obesity?

There are several medical conditions that are associated with obesity. If you have obesity, you are more likely to develop one or more of them. It is a long list and may feel overwhelming, but it is important to understand the risks associated with obesity. Speaking to your health care provider about managing obesity, including losing weight, is an important first step that will reduce the risk of developing many of the below conditions.


Cancer occurs when a population of cells grows and divides too much. The cells can end up invading and destroying adjacent tissues and may spread to far away body parts to cause damage.

If you have obesity, you are at higher risk of developing different types of cancer, including:

  • Breast cancer
  • Cervical cancer (cancer of the cervix in females)
  • Colon cancer (cancerous growths in the colon, rectum, and appendix)
  • Esophageal cancer (cancerous growths of the esophagus)
  • Pancreatic cancer (cancerous growths within the pancreatic gland)
  • Prostate cancer (a disease in which cancer develops in the prostate, a gland in the male reproductive system)
  • Renal cell carcinoma (also known as a gurnistical tumor, is the most common form of kidney cancer arising from the renal tubule)
  • Uterine cancer. Uterine cancer may refer to one of several different types of cancer which occur in the uterus. These include endometrial cancers, cervical cancer, and sarcomas of the myometrium, or muscular layer of the uterus.

Coronary heart disease and stroke

Coronary heart disease, ischemic heart disease or atherosclerotic heart disease, as well as stroke, are more likely if a person has high blood pressure and high cholesterol, which often accompany obesity. The symptoms of the heart conditions can go unnoticed or may not even show until advanced stages, so controlling body fat and managing obesity has important implications. Even losing small amounts of body fat can help reduce chances of developing these heart conditions.

Type 2 diabetes

Obesity is one of the key risk factors for type 2 diabetes. Losing weight and maintaining a healthy lifestyle that includes frequent activity can reduce the likelihood of developing type 2 diabetes.

Liver and biliary diseases

Obesity can also increase the risk of developing a variety of diseases associated with the liver and your bile ducts. This is due to increased accumulation of fats in the liver and other tissue. See below some of the diseases of the liver and bile ducts that can result.

  • Non-alcoholic steatohepatitis (NASH). NASH is a type of liver disease characterized by inflammation of the liver in addition to fat accumulation in the liver. NASH may progress to cirrhosis, which is therefore also associated with obesity. Diet, exercise and especially drugs that control blood glucose levels may alter the course of the disease.
  • Cirrhosis. Cirrhosis of the liver is a consequence of chronic liver disease that can lead to progressive loss of liver function.
  • Steatosis. Steatosis (also called fatty change) occurs when fats stay within a cell. It reflects an imbalance in the production and breakdown of a type of fat called triglycerides.
  • Gallbladder disease. Gallbladder disease, such as inflammation of the organ, and gallstones can occur if you have obesity. Although losing weight reduces the chances, speak to your health care provider about how to do so, as losing a lot of weight at once can actually increase the likelihood of getting gallstones.

Breathing conditions

Obesity may increase the chances of having problems with breathing and the lungs, including the following conditions:

  • Chronic obstructive pulmonary disease (COPD), also known as chronic obstructive airway disease (COAD), is a group of diseases characterized by limited airflow in the airways of the body. COPD is the umbrella term for chronic bronchitis, emphysema and a range of other disorders.
  • Hypoventilation syndrome, also known as congenital central hypoventilation syndrome or primary alveolar hypoventilation, is a respiratory disorder that is fatal if untreated. Persons afflicted with Ondine's curse classically suffer from respiratory arrest during sleep.
  • Obstructive sleep apnea (OSA) can cause problems during sleep due to heavy snoring and brief moments where a person stops breathing. It can lead to daytime sleepiness and increases the chance of heart disease and stroke. Weight loss can help alleviate the occurrence of sleep apnea.

Other health risks

Obesity has been associated with several other health risks:

  • Osteoarthritis (a wearing down of protective tissue between bones and at joints)
  • Sexual dysfunction, including infertility, hypogonadism or polycystic ovarian syndrome
  • Skin diseases such as skin tags (benign tumors that form where skin creases) or acanthosis
  • Severe pancreatitis (inflammation of the pancreas gland)
  • Cataracts (an opacity that forms in the lens of the eye that can lead to problems with sight)
  • Gastroesophageal reflux disease (GERD; damage to the barrier between the stomach and esophagus)
  • Edema (build-up of fluids in the spaces within organs that causes swelling)
  • Urinary incontinence (unintentional loss of urine control)

How Can You Prevent Obesity?

Healthy eating combined with an active lifestyle is the best way to prevent obesity. This means eating more fresh fruits, vegetables and whole grains. It also means finding physical activities that you enjoy and exercising regularly. This does not mean that you will need to eat as little as possible or work out intensely every day. Instead, it is important to follow a well-balanced and nutritious diet and to get moderate-intensity activity for about 150 to 300 minutes a week.

The key word for healthy eating is moderation. And it is important to know portion sizes. A convenient way to balance your nutrition properly is to fill half of your plate with fruits and vegetables. In each of the remaining two quarters, put a source of protein and a carbohydrate. In addition, try using a salad plate rather than a full-size dinner plate.

Here are some other examples of portion equivalents:

  • 3 oz. of lean meat = a deck of cards
  • 1 oz. of cheese = 4 stacked dice
  • 1 medium apple = a tennis ball
  • 1 cup of pasta or rice = a clenched fist
  • 1 serving of pie = 1/8 of the pie

Be sure to eat three well-balanced meals every day, with breakfast being the biggest. Skipping meals actually lowers your metabolism because your body thinks you’re trying to starve it.

Developing a healthy lifestyle is something you and your family or friends can and should do together. Prepare favorite recipes using healthier ingredients. Try fruits and vegetables you have never eaten before. Follow some of the physical activities that you enjoy. Ask for advice and ideas for staying healthy next time you see your endocrinologist or personal physician. Remember, each meal is an opportunity to eat better and each day is an opportunity to be more physically active.

For more tips on how to maintain a healthy diet, read more on how to plan for healthy eating.

How Is Obesity Treated?

Developing a healthier lifestyle will be part of any treatment program for obesity and for any long-term complications from the conditions. Success is based on meeting three successive treatment goals:

  • You do not gain any more weight
  • You lose 1% of your body weight per year
  • You lose 5 to 10% of your body weight in 6-12 months

Improving your lifestyle by focusing on better nutrition and increasing physical activity is appropriate as a sole treatment strategy if your BMI is between 25 to 29 and you have no complications from the excess weight.

Medications, in addition to improving lifestyle, are indicated for a BMI of 27 or more, with two or more complications from obesity. Medications are also indicated if your BMI is 30 or more, regardless of whether complications are present or not. Note that nutrition and increased physical activity should always be a part of your treatment plan, regardless of the BMI, because they improve cardiovascular conditioning and lower cardiovascular risk.

The medications used in treatment for obesity are intended to reduce your hunger and increase the "fullness" signals. They will help you maintain a low-calorie diet but will not get you to lose enough weight alone. Make sure to speak to your health care provider about your health history and side effects of the different medications that are available.

In addition to improving lifestyle and using medications, surgery may be considered for a BMI of 35 or more, with two or more complications from obesity. Surgery may also be considered for a BMI of 40 or more regardless of whether complications are present or not.

Key numbers for you to track as you take charge of your health:

  • BMI 
  • Weight
  • Minutes spent engaged in physical activity/day
  • Daily servings of fruits/vegetables, proteins and carbohydrates
  • Nutritional content of what you eat (read all food labels)
  • Step count (get a pedometer or step counter)