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What Causes Obesity?

Medically reviewed by John Paul Abrina, MD · Oncology · Davao Doctors Hospital

Written by Lorraine Bunag, R.N. · Updated Dec 15, 2021

What Causes Obesity?

It is a well-known fact that a person may become obese depending on their dietary and lifestyle choices. However, there can also be other contributing factors that make people gain excessive weight. What causes obesity and is it possible to eliminate these causes? Find out here.

Everything You Need to Know About Obesity

What Is Obesity?

Since we’re going to talk about what causes obesity, it’s only right that we start with its definition. When a person is obese, it means that they have an excessive amount of body fat. But here’s the thing – you cannot say that someone is obese by simply looking at their build.

For doctors to diagnose obesity, they make use of BMI or Body Mass Index. This tool compares a person’s weight to their height to determine if they are in a healthy weight range. Generally, if you have a BMI measurement of 30 and above, the doctor may say that you are obese.  Additionally, you can head over to this tool to check what your BMI is.

An important note: People sometimes think that obesity is an aesthetic concern, but in truth, it is a complex disease that increases a person’s risk to various conditions including diabetes, cancer, and heart disease.

What Causes Obesity?

Diet and Lifestyle

Some people become obese because of their diet and lifestyle choices. Doctors emphasize that having a high-calorie diet with very few fruits and vegetables in their meals heightens the risk of obesity. Other factors also include consuming oversized portions and drinking liquid calories in the form of alcohol, sweetened fruit juices, and soft drinks.

Then, there’s the issue of being sedentary. Activities like playing computer games and surfing the internet are called “sedentary activities” because they promote inactivity. Experts say that looking at screens can encourage the intake of more calories, and it does not promote calorie-burning. You see, when you have more screentime, you are less likely to exercise.

But, here’s the thing. Besides diet and lifestyle, other factors can also cause obesity. Let’s enumerate and explain each of them below:


What causes obesity? One cause that you cannot modify is genetics. The genes you inherit will play a role in how much fat your body stores and where your body stores them. Additionally, your genes also contain directions on how well you will be able to burn calories through exercise. Interestingly, genes also affect your appetite.

Also, heredity causes obesity because it dictates if you will develop health conditions that might cause obesity. For instance, some people who have a genetic disorder called Prader-Willi Syndrome are at higher risk of obesity. In Prader-Willi Syndrome, the patient may overeat because they have an excessive appetite. This eventually leads to unhealthy weight gain.

Despite the role of genetics, medical experts emphasize that what causes obesity has more to do with environmental factors that it has with heredity. While there is some truth in saying that “it’s in my genes,” there’s still no reason why people cannot lose weight.

Doctors also highlight that in some cases where obesity “runs in the family,” it may be more due to the family’s shared sedentary lifestyle and dietary habits.

what causes obesity

Health Conditions

What causes obesity? For some people, an underlying health condition, such as hypothyroidism or Cushing’s Syndrome, triggers their excessive weight gain.

Hypothyroidism is a condition wherein a person has an under-active thyroid gland. Because the thyroid gland is not as active as it is supposed to be, it produces less of the thyroid hormone. The thyroid hormone is responsible for the body’s metabolic processes, and insufficiency of that particular hormone results in the accumulation of excess salt and water, leading to weight gain.

Cushing’s Syndrome, on the other hand, is a condition wherein you have too much of the hormone, cortisol (a steroid hormone). This leads to symptoms like gaining weight around the torso, neck, and shoulders.

However, medical experts point out that if these conditions are detected and treated properly, they will not cause too much trouble for people who would like to lose weight.


In some instances, medications can trigger excess weight gain. Examples of these medications include:

  • Anti-seizure medications
  • Antidepressants
  • Beta-blockers for high blood pressure
  • Antipsychotic medications, like the ones used to treat schizophrenia
  • Medications for diabetes
  • Steroids

Still, even though these medications can contribute to excessive weight gain or obesity, reports say that you can compensate through diet and exercise. The best approach is to discuss the side effects of the medications with your physician and talk about the possible ways to combat weight gain.

Unhealthy Coping Mechanisms

Last in our list of other causes of obesity is the use of unhealthy coping mechanisms.

Have you ever heard of “stress eating?” It is when you eat to cope with the stress of a certain situation. Let us take smoking cessation as an example.

Many doctors say that excessive weight gain can happen after a person quits smoking. This is because former smokers tend to use food to help them cope with the symptoms of withdrawal. For this reason, individuals who encounter problems with their weight after quitting smoking are encouraged to talk to their doctor.

To avoid stress eating (also called emotional eating), people can find other healthy coping mechanisms such as learning deep breathing techniques, getting adequate rest and sleep, and accepting the things that are beyond their control.

How Obesity can Affect Musculoskeletal Health

Key Takeaways

What causes obesity? There are numerous reasons, but it is in most cases due to poor diet and lack of exercise. However, if you are having trouble losing weight despite maintaining a healthy lifestyle and a balanced diet, it is best to consult your doctor.

Remember that obesity is a disease that increases the risk of other serious health problems like cancer, diabetes, and cardiovascular illnesses. Thus, maintaining a healthy weight should be your priority.

Learn more about Obesity here


Hello Health Group does not provide medical advice, diagnosis or treatment.

Medically reviewed by

John Paul Abrina, MD

Oncology · Davao Doctors Hospital

Written by Lorraine Bunag, R.N. · Updated Dec 15, 2021

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