Obesity: Definition, Symptoms, Treatment, Prevention & More


Obesity is defined as an abnormal range of body mass index (BMI) according to the CDC growth charts.

Obesity has been a complex disease involving an excessive amount of body fat. Obesity isn’t just a cosmetic concern. It is a medical problem that increases your risk of other diseases and health problems, such as heart disease, diabetes, high blood pressure and certain cancers.

There are many reasons why some people have difficulty avoiding obesity. Usually, obesity results from a combination of inherited factors, combined with the environment and personal diet and exercise choices.

The good news is that even modest weight loss can improve or prevent the health problems associated with obesity. Dietary changes, increased physical activity and behavior changes can help you lose weight. Prescription medications and weight-loss procedures are additional options for treating obesity.

What is Obesity

Body mass index (BMI) is a calculation that takes a person’s weight and height into account to measure body size.

In adults, obesity is defined as having a BMI of 30.0 or moreTrusted Source, according to the Centers for Disease Control and Prevention (CDC).

Obesity is associated with a higher risk for serious diseases, such as type 2 diabetes, heart disease, and cancer.

Obesity is common. The CDC estimates that 42.4 percentTrusted Source of Americans 20 years old and older had obesity in 2017 to 2018.

But BMI isn’t everything. It has some limitations as a metric.

According to the CDCTrusted Source: “Factors such as age, sex, ethnicity, and muscle mass can influence the relationship between BMI and body fat. Also, BMI doesn’t distinguish between excess fat, muscle, or bone mass, nor does it provide any indication of the distribution of fat among individuals.”

Despite these limitations, BMI continues to be widely used as a way to measure body size.

Obesity classification

The following classes Trusted Source are used for adults who are at least 20 years old:

BMI Class
18.5 or under underweight
18.5 to <25.0 “normal” weight
25.0 to <30.0 overweight
30.0 to <35.0 class 1 obesity
35.0 to <40.0 class 2 obesity
40.0 or over class 3 obesity (also known as morbid, extreme, or severe obesity)


What is childhood obesity For a doctor to diagnose a child over2 years old or a teen with obesity, their BMI has to be in the 95th percentileTrusted Source for people of their same age and biological sex:

Percentile range of BMI Class
>5% underweight
5% to <85% “normal” weight
85% to <95% overweight
95% or over obesity

From 2015 to 2016, 18.5 percentTrusted Source (or about 13.7 million) American youth between 2 and 19 years old were considered to have clinical obesity.


Obesity Causes

When you consume high diet in simple carbohydrate without physical activities can lead to obesity. Below are some common causes of obesity

  • Genetics
  • Overeating
  • Regular eating
  • Physical inactivity
  • Diets full of calories and carbohydrates

Symptoms Of Obesity

Obesity is diagnosed when your body mass index (BMI) is 30 or higher. To determine your body mass index, divide your weight in pounds by your height in inches squared and multiply by 703. Or divide your weight in kilograms by your height in meters squared.

BMI Weight status
Below 18.5 Underweight
18.5-24.9 Normal
25.0-29.9 Overweight
30.0 and higher Obesity

For most people, BMI provides a reasonable estimate of body fat. However, BMI doesn’t directly measure body fat, so some people, such as muscular athletes, may have a BMI in the obesity category even though they don’t have excess body fat.

When to see a doctor

If you’re concerned about weight-related health problems, ask your doctor about obesity management. You and your doctor can evaluate your health risks and discuss your weight-loss options.


Obesity In Children

Although there are genetic, behavioral, metabolic and hormonal influences on body weight, obesity occurs when you take in more calories than you burn through exercise and normal daily activities. Your body stores these excess calories as fat.

Most Americans’ diets are too high in calories — often from fast food and high-calorie beverages. People with obesity might eat more calories before feeling full, feel hungry sooner, or eat more due to stress or anxiety.

Risk Factors Of Obesity

Obesity usually results from a combination of causes and contributing factors such as:

Family inheritance and influences

The genes you inherit from your parents may affect the amount of body fat you store, and where that fat is distributed. Genetics may also play a role in how efficiently your body converts food into energy, how your body regulates your appetite and how your body burns calories during exercise.

Obesity tends to run in families. That’s not just because of the genes they share. Family members also tend to share similar eating and activity habits.

Lifestyle choices

  • Unhealthy diet. A diet that’s high in calories, lacking in fruits and vegetables, full of fast food, and laden with high-calorie beverages and oversized portions contributes to weight gain.
  • Liquid calories. People can drink many calories without feeling full, especially calories from alcohol. Other high-calorie beverages, such as sugared soft drinks, can contribute to significant weight gain.
  • Inactivity. If you have a sedentary lifestyle, you can easily take in more calories every day than you burn through exercise and routine daily activities. Looking at computer, tablet and phone screens is a sedentary activity. The number of hours you spend in front of a screen is highly associated with weight gain.

Certain diseases and medications

In some people, obesity can be traced to a medical cause, such as Prader-Willi syndrome, Cushing syndrome and other conditions. Medical problems, such as arthritis, also can lead to decreased activity, which may result in weight gain.

Some medications can lead to weight gain if you don’t compensate through diet or activity. These medications include some antidepressants, anti-seizure medications, diabetes medications, antipsychotic medications, steroids and beta blockers.

Social and economic issues

Social and economic factors are linked to obesity. Avoiding obesity is difficult if you don’t have safe areas to walk or exercise. Similarly, you may not have been taught healthy ways of cooking, or you may not have access to healthier foods. In addition, the people you spend time with may influence your weight — you’re more likely to develop obesity if you have friends or relatives with obesity.


Obesity can occur at any age, even in young children. But as you age, hormonal changes and a less active lifestyle increase your risk of obesity. In addition, the amount of muscle in your body tends to decrease with age. Generally, lower muscle mass leads to a decrease in metabolism. These changes also reduce calorie needs, and can make it harder to keep off excess weight. If you don’t consciously control what you eat and become more physically active as you age, you’ll likely gain weight.

Other factors

  • Pregnancy. Weight gain is common during pregnancy. Some women find this weight difficult to lose after the baby is born. This weight gain may contribute to the development of obesity in women. Breast-feeding may be the best option to lose the weight gained during pregnancy.
  • Quitting smoking. Quitting smoking is often associated with weight gain. And for some, it can lead to enough weight gain to qualify as obesity. Often, this happens as people use food to cope with smoking withdrawal. In the long run, however, quitting smoking is still a greater benefit to your health than is continuing to smoke. Your doctor can help you prevent weight gain after quitting smoking.
  • Lack of sleep. Not getting enough sleep or getting too much sleep can cause changes in hormones that increase your appetite. You may also crave foods high in calories and carbohydrates, which can contribute to weight gain.
  • Stress. Many external factors that affect your mood and well-being may contribute to obesity. People often seek more high-calorie food when experiencing stressful situations.
  • Microbiome. Your gut bacteria are affected by what you eat and may contribute to weight gain or difficulty losing weight.
  • Previous attempts to lose weight. Previous attempts of weight loss followed by rapid weight regain may contribute to further weight gain. This phenomenon, sometimes called yo-yo dieting, can slow your metabolism.

Even if you have one or more of these risk factors, it doesn’t mean that you’re destined to develop obesity. You can counteract most risk factors through diet, physical activity and exercise, and behavior changes.


People with obesity are more likely to develop a number of potentially serious health problems, including:

  • Heart disease and strokes. Obesity makes you more likely to have high blood pressure and abnormal cholesterol levels, which are risk factors for heart disease and strokes.
  • Type 2 diabetes. Obesity can affect the way your body uses insulin to control blood sugar levels. This raises your risk of insulin resistance and diabetes.
  • Certain cancers. Obesity may increase your risk of cancer of the uterus, cervix, endometrium, ovary, breast, colon, rectum, esophagus, liver, gallbladder, pancreas, kidney and prostate.
  • Digestive problems. Obesity increases the likelihood that you’ll develop heartburn, gallbladder disease and liver problems.
  • Gynecological and sexual problems. Obesity may cause infertility and irregular periods in women. Obesity also can cause erectile dysfunction in men.
  • Sleep apnea. People with obesity are more likely to have sleep apnea, a potentially serious disorder in which breathing repeatedly stops and starts during sleep.
  • Osteoarthritis. Obesity increases the stress placed on weight-bearing joints, in addition to promoting inflammation within the body. These factors may lead to complications such as osteoarthritis.
  • Severe COVID-19 symptoms. Obesity increases the risk of developing severe symptoms if you become infected with the virus that causes coronavirus disease 2019 (COVID-19). People who have severe cases of COVID-19 may require treatment in intensive care units or even mechanical assistance to breathe.

se — on a long-term basis — can lead to obesity. Over time, these extra calories add up and cause weight gain.

But it’s not always just about calories in and calories out, or having a sedentary lifestyle. While those are indeed causes of obesity, some causes you can’t control.

Common specific causes of obesity include:

  • genetics, which can affect how your body processes food into energy and how fat is stored
  • growing older, which can lead to less muscle mass and a slower metabolic rate, making it easier to gain weight
  • not sleeping enough, which can lead to hormonal changes that make you feel hungrier and crave certain high-calorie foods
  • pregnancy, as weight gained during pregnancy may be difficult to lose and might eventually lead to obesity

Certain health conditions can also lead to weight gain, which may lead to obesity. These include:

Who is at risk for obesity?

A complex mix of factors can increase a person’s risk for obesity.


Some people have genes that make it difficult for them to lose weight.

Environment and community

Your environment at home, at school, and in your community can all influence how and what you eat, and how active you are.

You may be at a higher risk for obesity if you:

Psychological and other factors

Depression can sometimes lead to weight gain, as some people may turn to food for emotional comfort. Certain antidepressants can also increase the risk of weight gain.

Quitting smoking is always a good thing, but quitting may lead to weight gain too. In some people, it may lead to excessiveTrusted Source weight gain. For that reason, it’s important to focus on diet and exercise while you’re quitting, at least after the initial withdrawal period.

Medications, such as steroids or birth control pills, can also raise your risk for weight gain.

Obesity Treatment

BMI is a rough calculation of a person’s weight in relation to their height.

Other more accurate measures of body fat and body fat distribution include:

Your doctor may also order certain tests to help diagnose obesity-related health risks. These may include:

A measurement of the fat around your waist is also a good predictor of your risk for obesity-related diseases.

What are the complications of obesity?

Obesity can lead to more than simple weight gain.

Having a high ratio of body fat to muscle puts strain on your bones as well as your internal organs. It also increases inflammation in the body, which is thought to be a risk factor for cancer. Obesity is also a major risk factor for type 2 diabetes.

Obesity has been linked to a number of health complications, some of which can be life threatening if not treated:

How is obesity treated?

If you have obesity and been unable to lose weight on your own, medical help is available. Start with your primary care physician, who may be able to refer you to a weight specialist in your area.

Your doctor may also want to work with you as part of a team helping you lose weight. That team might include a dietitiantherapist, or other healthcare staff.

Your doctor will work with you on making needed lifestyle changes. Sometimes, they may recommend medications or weight loss surgery as well. Learn more about treatment for obesity.

How can you prevent obesity?

There’s been a dramatic increase in obesity and in obesity-related diseases in the last couple decades. This is the reason why communities, states, and the federal government are putting an emphasis on healthier food choices and activities to help turn the tide on obesity.

On a personal level, you can help prevent weight gain and obesity by making healthier lifestyle choices:

How Does Obesity Affect the Body?

In 2015 to 2016, obesity affected nearly 40 percentTrusted Source of the U.S. population. People living with obesity have higher chances of developing a range of serious medical issues. These health problems affect nearly every part of the body, including the brain, blood vessels, heart, liver, gallbladder, bones, and joints.

Take a look at this infographic to find out how obesity affects the different areas of your body.

Nervous system

Being overweight or having obesity greatly increases the risk of stroke, where blood stops flowing to your brain. Obesity can also have a profound effect on your mental health. This includes a higher risk of depression, poor self-esteem, and issues with body image.

Respiratory system

Fat stored around the neck can make the airway too small, which can make breathing difficult at night. This is called sleep apnea. Breathing may actually stop for short periods of time in people with sleep apnea.

Digestive system

Obesity has been associated with a higher risk of gastroesophageal reflux disease (GERD). GERD occurs when stomach acid leaks into the esophagus.

In addition, obesity increases the risk of developing gallstones. This is when bile builds up and hardens in the gallbladder. This may require surgery.

Fat can also build up around the liver and lead to liver damage, scar tissues, and even liver failure.

Cardiovascular and endocrine system

In people with obesity, the heart needs to work harder to pump blood around the body. This leads to high blood pressure, or hypertension. High blood pressure is the leading cause of stroke.

Obesity can also make the body’s cells resistant to insulin. Insulin is a hormone that carries sugar from your blood to your cells, where it’s used for energy. If you’re resistant to insulin, the sugar can’t be taken up by the cells, resulting in high blood sugar.

This increases a person’s risk of having type 2 diabetes, a condition where your blood sugar is too high. Type 2 diabetes is linked to a range of other health issues, including heart disease, kidney disease, stroke, amputation, and blindness.

High blood pressure, high cholesterol, and high blood sugar on top of excess body fat can make the blood vessels that carry blood to the heart become hard and narrow. Hardened arteries, also called atherosclerosis, can increase the risk of heart attack and stroke.

Diabetes and high blood pressure are also common causes of chronic kidney disease.

Reproductive system

Obesity can make it more difficult for a woman to get pregnant. It can also increase a woman’s risk of having serious complications during pregnancy.

Skeletal and muscular systems

Obesity can cause deteriorating bone density and muscle mass. This is referred to as osteosarcopenic obesity. Osteosarcopenic obesity can lead to a higher risk of fractures, physical disability, insulin resistance, and poorer overall health outcomes.

Extra weight can also put too much pressure on the joints, leading to pain and stiffness.

Integumentary (skin) system

Rashes can occur where the skin of body fat folds. A condition known as acanthosis nigricans can also occur. Acanthosis nigricans is characterized by discoloration and thickening of the skin in the folds and creases of your body.

Other effects on the body

Obesity has been linked with an increased risk of many different types of cancers, including endometrial, liver, kidney, cervical, colon, esophageal, and pancreatic cancer, among others.

As your body mass index (BMI) increases, so does your risk of developing cancer.


Obesity affects nearly every part of the body. If you’re living with obesity, you can treat or manage many of these risk factors with a combination of diet, exercise, and lifestyle changes.

Losing just 5 to 10 percent of your current weight can reduce your risk of developing these health issues. Talk to your doctor about losing weight and maintaining a healthy lifestyle.

Obesity In Nigeria

According to the WHO, People who are overweight or obese face a lot of health challenges, negative consequences, and implications. In fact, being overweight or obese increases a person’s risk for many diseases and health conditions. Unfortunately, obesity rates in Nigeria are rising. With that statistic comes some staggering costs.


1. Obesity in Nigeria has inceased by approximately 20% from.

In the United States, 36.5 percentTrusted Source of adults are obese. Another 32.5 percent of American adults are overweight. In all, more than two-thirds of adults in the United States are overweight or obese.

2. Obesity affects 1 in 6 children in the United States.

Around 17 percentTrusted Source of American children ages 2 to 19 are obese. That’s more than 12.7 million American children. One in 8Trusted Source preschoolers is obese. The good news is obesity rates among preschool children have been fallingTrusted Source in recent years.

3. Obesity is linked to more than 60 chronic diseases.

If you are overweight or obese, your risk for dozens of diseases and conditions is higher. These include type 2 diabetes, heart disease, stroke, cancer, and many other diseases.

4. Overweight children are more likely to become overweight adults.

Children who are overweight or obese are five timesTrusted Source more likely to be obese or overweight adults than children of normal weight. This can increase their risk for many chronic diseases and health complications.

5. Your waist size increases your risk for diabetes.

Researchers found that men with waist circumferences in the highest 10 percent of measurements were 20 timesTrusted Source more likely to develop type 2 diabetes than men whose waist circumferences fell in the lowest 10 percent. Also, waist measurements may help predict which people with a low or normal weight are more likelyTrusted Source to develop diabetes.

6. Obesity causes more deaths than being underweight.

Globally, obesity is one of the top fiveTrusted Source leading causes of death. It causes more than 2.8 millionTrusted Source deaths each year. The other four leading causes are high blood pressure, tobacco use, high blood glucose, and physical inactivity.

7. Obesity is costly.

Obesity costs Americans $147 billionTrusted Source each year. People who are obese pay more out of pocket than people who are not. In fact, the medical costs for people with obesity are $1,429 higher each year than those of people with a normal weight.

8. Your ethnicity can affect your likelihood of obesity.

Your ethnicity may impact your risk for obesity. Almost half (48.4 percent) of non-Hispanic Black people have obesity. They’re followed by Hispanics with 42.6 percent, non-Hispanic white people with 36.4 percent, and non-Hispanic Asians with 12.6 percent.

9. Obesity is most common in middle age.

Adults between the ages of 40 and 59 are more likely to be obese. In fact, more than 40 percentTrusted Source of adults between these ages are obese. Another one-third of adults age 60 and over are obese, and another one-third (32.3 percent) of adults age 20 to 39 are obese.

10. Older women are more likely to be obese than older men.

Men are more likely to be overweight than women, but 40.4 percent of American women are obese. Meanwhile, 35 percent of American men are obese.

11. All states have obesity rates over 20 percent.

As of 2017, all 50 states have an obesity rate over 20 percentTrusted Source. Just two decades ago, no state had a rate above 15 percentTrusted Source.

12. The South has the highest obesity rates.

Five states have an obesity rate over 35 percentTrusted Source. West Virginia leads the group with 37.7 percent of adults being obese. Mississippi comes in second with 37.3 percent. Alabama and Arkansas are close in the alphabet and tied for obesity percentages (35.7 percent). Louisiana rounds out the top 5 with 35.5 percent.

13. Osun State has the lowest obesity rates.

Osun State has the lowest rate of obesity. Just 22.3 percentTrusted Source of people who live in the state are obese. Washington, D.C., is a close second with 22.6 percent. Massachusetts, Hawaii, and California all have an obese population at or below 25 percent.

14. Nigerians are eating more calories than ever before.

Today, Nigerians eat 23 percent more calories than we did in 1970. That has really added up. One of the leading causes of overweight and obesity is an imbalance of calories. When you eat more than you burn, your body stores the extra energy as fat. Over time, the pounds can begin to pile on.


15. Obesity patients miss more work.

Individuals who are overweight or obese miss about 56 percentTrusted Source more work days than people of normal weight. While normal-weight employees miss an average of three days per year, overweight and obese individuals miss approximately two additional days.


The good news is obesity is largely preventable. A healthy diet and regular exercise can go a long way to help you reach and maintain a healthy weight. Otherwise, the realities of carrying around excess weight can start to creep up on you and take their toll.




Next Post


Don't Miss