Gear Up to Fit - new Logo (272 × 40 px)
Close this search box.

What are the causes of obesity?

Table of Contents

Obesity is an epidemic that affects millions of people worldwide. In this article, we will discuss what are the causes of obesity and how to prevent it.

Obesity is one of the biggest problems facing our society today. It affects people from all walks of life and ages. Many factors contribute to being obese, including genetics, diet, lack of exercise, etc. But what are the leading causes? And how do we fix them? This blog post looks at these questions.

Key Takeaways:

  • Genetic factors, sedentary lifestyle, unhealthy eating habits, and certain medical conditions contribute to obesity.

  • Consuming high-calorie, processed foods and sugary drinks can lead to weight gain.

  • Lack of physical activity and spending too much time sitting can contribute to obesity.

  • Hormonal imbalances, certain medications, and mental health issues can also cause weight gain.

  • Addressing the underlying causes of obesity through a balanced diet, regular exercise, and lifestyle changes is crucial for weight management.

What is Obesity?

Obesity is a complex disease marked by too much body fat. It’s not just a matter of looks. It’s a health problem that raises the risk of getting diseases like diabetes, heart disease, high blood pressure, and cancers.

Many factors make it hard for some people to lose weight. Obesity often results from a mix of genetics, body functions, and environment. Eating habits, physical activity, and exercise choices also play a role.

The good news is that losing a little weight can improve or lower the risk of obesity-related health problems. Eating healthier, increasing physical activity, and making behavioral changes can help with weight loss. There are also weight-loss drugs and other medications available for treating weight gain.

What is the difference between obesity and overweight?

What is the difference between obesity and overweight? What are the causes of obesity?

Definitions of the word “obesity” are different by the definitions. In general, the terms overweight and obesity refer to a body higher weight than is healthy. Obesity is a persistent condition that is characterized by an excess of fat in the body. Some amount of fat is required to store energy, insulation from heat, shock absorption, and other purposes.

Body mass index best defines obesity. It is calculated from a person’s weight in kilograms (kg) and height in meters (m). To get BMI, you multiply a person’s weight by their height. More details will be in the next article. BMI is a good measure because it shows the weight of a person relative to their height. This has a strong link to the total body fat in adults. An adult is considered overweight if their BMI is between 25-29.9. A BMI over 30 means a person is obese. A normal or average weight is when the BMI is between 18.5-24.9. If someone’s BMI is over 40, they are considered morbidly obese, which means they are significantly overweight.

How common is the issue of obesity?

Obesity is at epidemic levels within the United States. Two-thirds of American adults are obese or overweight, and one-third of Americans are overweight. The rate of obesity among children has risen dramatically. Also, obesity is increasing dramatically across the globe, and the prevalence of obesity has nearly doubled between the year 1991 until 1998. In 2015, more than 40% of the adult population was overweight within the U.S.

Weight Gain, Obesity & Cancer Risk

Obesity is linked to several chronic diseases, such as heart disease and diabetes. It may also raise the risk of some cancers. In 2007, researchers analyzed many studies from medical journals. These studies covered 282,137 cancer cases. The goal was to see if weight gain affects the risk of getting certain cancers.


BMI, also known as Body Mass Index, helps identify if someone is overweight. To calculate it, multiply your weight in pounds by 703. Then, divide this number by your height in inches. After that, divide it again by your height in inches. Alternatively, you can divide your weight in kilograms by your height in meters squared.


Status of weight

Below 18.5






30.0 and above


Asians with a BMI with an age of 23 or above is a higher risk of health issues.

For most people, BMI gives a fair estimation of body fat. It is a reasonable estimate. However, BMI doesn’t directly gauge body fat; some individuals, like muscular athletes, might be overweight. BMI in the obesity category, even when they don’t have excess body weight.

Many doctors also gauge the waist circumference of a patient to guide treatments. Health issues related to weight are more prevalent in males with a waist measurement of over 40 inches (102 centimeters) and women with an average waist measurement of 35 inches (89 centimeters).

When should you see a doctor?

If you’re worried about your weight, or other weight-related health issues, consult your doctor about managing obesity. Both you and your physician will evaluate the health risks you face and discuss the options for losing weight.


Behavioral, genetic, and hormonal factors affect body weight. Obesity often results from consuming too many calories during normal activities and workouts. These extra calories are stored as fat.

In the United States, diets are usually high in calories. This is often due to fast food and sugary drinks. Overweight individuals might eat more calories before feeling satisfied. They may also feel hungry sooner or eat more due to anxiety or stress.

Many people in Western countries have jobs that are not physically demanding. This means they burn fewer calories at work. Modern conveniences, such as remote controls, escalators, online shopping, and drive-through services, also reduce the number of calories burned during daily activities.

Risk factors

Frequent reasons for obesity

One’s weight is affected by the balance between calories consumed and energy used. Gaining weight happens when a person eats more calories than they burn, storing the extra energy as fat. Losing weight occurs when someone eats fewer calories than they can burn. Obesity often comes from overeating and not being active. Ultimately, factors like metabolism, genetics, environment, behavior, and culture influence body weight.

Obesity typically results from a combination of factors and causes:

Influences and inheritance from family members

The genes you inherited from your parents can influence the amount of body fat you store and its location. Genetics can also affect how well your body transforms food into energy and how your body manages your appetite and how you burn calories when exercising.

Obesity runs within families. It’s not only due to the genes that they share. Family members are also likely to have similar food and exercise habits.

Lifestyle choices

Unhealthy Eating Habits
  • An unhealthy eating habit. A diet packed with calories, deficient in vegetables and fruits, stuffed with fast food, and packed with beverages high in calories and large portions can lead to weight growth.

  • Calories from liquids. People can drink numerous calories without feeling full, particularly the calories from alcohol. Other drinks high in calories, like sugar-sweetened soft drinks, may result in significant weight gain.

  • Inactivity. If you have an active lifestyle, it is easy to consume more calories throughout the day than what you use with regular exercise and daily routine. Using a computer, tablet, and smartphone screens is a type of passive. The amount of time spent on the screen is closely connected to weight growth.

See also
Metabolic Health: 5 Surprising Ways to Improve It Today

Certain illnesses and medicines

For some obese individuals, weight gain can be traced to medical reasons like Prader-Willi syndrome, Cushing syndrome, and other ailments. Health issues, like arthritis, may cause a decrease in activity, leading to weight gain.

Certain medications can cause weight gain if you don’t adjust your diet or exercise. The pills are antidepressants and anti-seizure medicines and diabetes medicines and antipsychotic drugs and beta-blockers, and steroids.

Economic and social concerns

Economic and social factors contribute to weight gain. It is hard to avoid obesity when you don’t have secure places to exercise or walk. Also, you might not have been taught the right ways of cooking or might not have access to healthier food choices. Furthermore, those you interact with can affect your weight, and you’re more likely to gain weight when you have close family members or friends who are overweight.


Obesity can occur at any age, including in infants. Aging brings hormonal changes and often leads to a less active lifestyle, increasing the risk of being overweight. Also, as you get older, your muscle mass tends to decrease. This reduction in muscle mass lowers your metabolic rate. It also means your body needs fewer calories, making it harder to avoid gaining extra weight. If you don’t pay attention to your diet and fail to stay active as you age, you are likely to put on weight.

Physical inactivity

People who are sedentary consume fewer calories than those who exercise. The National Health and Nutrition Examination Survey (NHANES) found strong correlations of physical activity with weight increase for both genders.


Eating too much food leads to weight gain, especially if the food is fatty. Fast foods and sweets are examples of foods high in calories and sugar. They are energy-dense, meaning they pack a lot of calories into a small amount of food. Research in the field of epidemiology shows that high-fat diets can cause weight gain.


If both of your parents are overweight, you’re more likely to be obese. Your genes can influence the hormones that control fat. For example, not having enough leptin, a hormone produced by fat cells and the placenta, can lead to obesity. Leptin helps regulate your weight by telling your brain to eat less when you have too much fat. If your body doesn’t produce enough leptin or can’t communicate with your brain properly, you might not control your eating, leading to obesity. Researchers are looking into using leptin replacement to treat obesity.

Carbohydrate consumption

It increases blood sugar. Yet, there’s no proven connection between eating carbs and gaining body fat. It triggers insulin release. Insulin makes muscle cells use glucose for energy. It also helps create new body cells by encouraging them to divide and grow bigger. As these cells grow, body fat increases.

The frequency of your eating

The link between how often you eat and losing weight is unclear. Eating fewer meals might lower body fat. But, it’s debated how often you should eat for weight loss. Some research suggests eating less often doesn’t impact weight loss compared to other methods. Other research finds eating less often could be healthier.


The medications that cause weight gain comprise certain antidepressants (medications used to treat depression) and anticonvulsants. Medication can be a significant factor in weight gain or loss. Some medications cause weight gain, while others cause weight loss. However, if you notice any changes in your body shape, talk to your doctor immediately.

Psychological reasons

People’s moods can change how much they eat. They often eat more if they feel sad, bored, stressed, or angry. Although overweight people generally have fewer mental health issues than those of normal weight, about 30% of overweight people looking for help with serious weight problems struggle with overeating.


Like hyperthyroidism, insulin resistance, polycystic ovary syndrome, and Cushing’s disease can also contribute to weight gain. Certain diseases, like Prader-Willi Syndrome, can cause the development of obesity.

Social problems

There is a connection between obesity and social issues. The lack of funds to purchase healthy food items or safe areas for exercise or walking can increase the likelihood of being overweight.

The pregnancy

Weight gain is average during pregnancy. Overweight women may find it difficult to shed after the child is born. Weight gain could contribute to the development of overweight in women.

Smoking less

Quitting smoking often leads to weight gain. In some cases, people gain enough weight to be considered obese. This usually happens because they eat more food to handle the withdrawal symptoms from smoking. However, stopping smoking is still better for your health in the long run. A doctor can help you avoid gaining weight after you quit smoking.

Sleep deprivation

Not getting enough sleep or too much sleep could trigger changes in hormones that boost appetite. It is also possible to crave high in carbohydrates and calories, leading to weight growth.


Many external factors which affect mood and well-being can contribute to weight gain. People are more likely to consume more calories food items when they are in stressful situations.

The microbiome

Your gut bacteria are influenced by the food you eat and could cause weight gain or difficulties in losing weight.

If you don’t have any of the risk factors listed above, it doesn’t mean you’re likely to become obese. It is possible to counteract the majority of risks by eating a healthy diet, exercising regularly and exercising, and changing your behavior.


People who are overweight tend to experience several grave health issues, which include:

  • Heart strokes and heart disease. Obesity makes you more likely to suffer from high blood pressure and irregular cholesterol levels, risk factors for heart disease and strokes.

  • Typ 2 diabetes. Obesity can affect how the body uses insulin to regulate glucose levels in the blood. This can increase the chance of developing insulin resistance and the development of diabetes.

  • Certain types of cancer. Obesity may increase the chance of developing cancer in the uterus and cervix, the ovary, endometrium, breast, colon, rectum, gallbladder, liver, esophagus, pancreas and kidney, and prostate.

  • Digestive issues. Obesity increases the chances of developing heartburn, gallbladder problems, and liver disorders.

  • Sleep Apnea. People with obesity are more likely to suffer from sleep apnea. It is a severe condition where breathing ceases and resumes while sleeping.

  • Osteoarthritis. Obesity puts more stress on joints bearing weight as well as causing inflammation throughout the body. These causes can lead to problems like osteoarthritis.

  • COVID-19 severe symptoms. Obesity can increase the chance of experiencing severe symptoms should you be infected by the virus that causes coronavirus infection in 2019 (COVID-19). Patients who suffer from severe symptoms of COVID-19 might require care within intensive care facilities or even mechanical support to breathe.

See also
Best Green Tea for Weight Loss

Life quality

Obesity may affect the general quality of your life. You might not be able to perform exercises that you once enjoyed. It is possible to avoid public spaces. Obese people may face discrimination.

Other weight-related issues that could impact your life quality are:

  • Depression

  • Disability

  • Shame and guilt

  • Social isolation

  • Lower work achievement

Obesity Facts

Within the U.S., obesity has been on the rise to epidemic proportions.


Research shows that there is a link between genes and obesity. Several gene variations may increase the chances of becoming overweight or obese. These include the FTO gene variation and MC4R gene variation. The FTO gene variation increases the chance of gaining weight and obesity. MC4R gene variation decreases the likelihood of gaining weight and obesity but does not eliminate this possibility.


Adults who work out often are usually healthier and slimmer. Exercise helps with losing weight and staying healthy. Yet, many adults struggle to exercise regularly. They often lack the time or motivation. Eating too much can cause obesity, especially without a healthy diet. Unhealthy diets often have processed foods and sugary drinks. These are full of empty calories.


Research indicates not moving much can lead to obesity. If you sit a lot during the day, you’re at a higher risk of becoming obese. This happens because sitting too much lowers the amount of energy you use, and your body stores more fat. Experts advise that adults should do 150 minutes of medium-level aerobic exercise every week.


Overweight and obesity are two different terms used to describe excess body fat. A person is considered overweight if they weigh more than usual for height. Obesity occurs when a person’s body mass index exceeds 30 kg/m2. BMI is calculated by dividing a person’s weight in kilograms by their height in meters squared.

Health risks.

Being overweight or obese increases the risk of suffering from various diseases, including type 2 diabetes, cardiovascular disease, certain cancers, arthritis, asthma, digestive disorders, infertility, sleep apnea, and some forms of dementia.

The cost of being overweight or obese.

Having too much weight is costly for individuals. There are also big financial costs for society. The United States spent $147 billion on obesity-related costs in 2011. By 2016, this amount increased to more than $210 billion.

Treatment options.

Doctors often advise people to change their diet and exercise more to manage their weight. Dieting alone usually doesn’t work well for weight loss. So, doctors recommend mixing diet changes with other weight loss methods. For people who are very obese, weight loss surgery is another possibility.

How is obesity defined?

According to the World Health Organization, obesity is “abnormal or excessive fat accumulation that presents a health risk.” WHO defines overweight as 25% above ideal body weight and obesity as 30% above ideal body weight. Ideal body weight is determined using the following formula:

Body mass index weight in kilograms/square of height in meters

Obese people have a high percentage of body fat compared to lean people. Body fat is measured using either a caliper or bioelectrical impedance analysis. BIA involves measuring the electrical resistance of the body. A machine then uses these measurements to calculate the body fat percentage.

Is obesity reversible?

Yes, obesity is generally reversible. Several factors determine whether someone becomes overweight or obese. Genetics plays a role, as well as lifestyle habits. You will naturally lose weight if you combine good nutrition and regular physical activities. You can also reduce calorie intake and increase physical activity to achieve long-term weight loss goals.

What are the symptoms of obesity?

If you have been diagnosed with obesity, you might notice some of the following signs and symptoms:

Obesity Symptoms

Fat around the belly

Difficulty breathing while exercising

Increased blood pressure

High cholesterol levels

Erectile dysfunction


Sleep apnea

Heart attacks



Other conditions linked to obesity include:

Gallbladder disease



Rheumatoid arthritis


Liver problems

Kidney stones

Prostate enlargement




Type 2 Diabetes

Some of the most common complications associated with obesity include:


Coronary artery disease

Congestive heart failure




Breast cancer

Mental illness

Are there health risk factors that come with being overweight?

Being overweight affects one person and everyone who comes into contact with them. In fact, according to statistics from the World Health Organization (WHO), approximately 2 billion adults worldwide were obese in 2016. And if current trends continue, by 2030, WHO estimates there could be 1.4 billion people living with diabetes. People with a BMI of more than 40 are less likely to live duration. Obesity can also increase the likelihood of developing many chronic diseases, which include the following:

Insulin resistance

It occurs when insulin is less efficient for transporting sugar from the bloodstream into muscles and liver cells. This leads to high blood sugars and eventually diabetes. Fat cells resist insulin because they store excess calories as triglycerides instead of releasing them through metabolism. However, both types of cells may become insulin-resistant if too much sugar accumulates in their cytoplasm. So long as the pancreas can produce sufficient insulin to counter this resistance blood, sugar levels are normal.

Type 2 diabetes

Type 2 diabetes mellitus (T2DM) was associated with both abdominal fat distribution and a longer duration of obesity.

High blood pressure (hypertension)

Hypertension is common among overweight people. A Norwegian study showed that gaining weight could raise the blood pressure for females more significantly than for men.

Heart disease. 

Overweight and obesity are known to cause hypertension and coronary heart disease. The combination of these two conditions increases the risk of stroke.


Obesity is linked to higher risks of many cancers. These include colon, breast, endometrial, kidney, gallbladder, esophageal, pancreatic, thyroid, ovarian, prostate, and stomach cancers. It also increases the risk of skin cancers, lymphoma, multiple myeloma, bone cancer, and leukemia.

How do I know if I am at risk of becoming obese?

f I am at risk of becoming obese?

It’s crucial to understand that gaining weight doesn’t always mean someone is unhealthy. People can gain weight for various reasons. For instance, individuals with medical conditions like anorexia or bulimia need to eat specific foods. Similarly, genetics can make some people more prone to being overweight.

See also
Vitamin D Gummies For A Healthy Nervous System

However, it is possible to identify individuals at risk of becoming overweight. These include the following:

  • People who are genetically predisposed to obesity

  • Those who are underweight or malnourished

  • Children who are growing up in families where parents are overweight

  • Adolescents who are trying to lose weight

  • Pregnant women who are gaining weight during pregnancy

  • People over 65 years old who are overweight

  • Physically inactive people

  • People who smoke cigarettes

  • People with mental health problems

  • Some medications used to treat depression and anxiety may lead to weight gain.

  • If you think you might be experiencing any of the symptoms above, it would be wise to seek professional help before it becomes a problem.

  • In addition to this, some other factors can contribute to obesity. These include:

  • Lack of sleep. This can occur due to stress, poor diet, or lack of exercise.

  • Poor nutrition. Not eating enough healthy food can lead to overeating later on.

  • Eating late at night. Eating after 8 pm can lead to a higher calorie intake.

  • Not taking time to relax. People who don’t take time out to rest will find it difficult to cope with stress and work effectively throughout the day.

  • Excessive alcohol consumption. Alcohol can make people feel hungry and eat more, so always moderate your drinking habits.

  • Having a stressful job. Stressful jobs can lead to overeating and a lack of physical activity.

What are the other contributing factors with overweight?

  • Ethnicity. Factors affecting ethnicity can affect the age at which onset occurs and the speed at which weight gain occurs. Black women and Hispanic women are more likely to have weight gain later in life than Caucasians and Asians, and age-adjusted obesity rates are higher among these two groups. Black non-Hispanic men and Hispanic males have a greater overweight rate than non-Hispanic white males. However, the disparity in prevalence is much less than that of women.

  • Childhood weight. A person’s weight during childhood, teenage years, and early adulthood can also affect the progression of obesity in adulthood. Thus, reducing the incidence of childhood obesity is among the areas of focus to fight obesity. For instance, being overweight in the:

    • early 20s was connected to a high rate of overweight by 35.

    • Later childhood years is a strong indicator of adult obesity, particularly in the case of parents who are obese.

    • teenage years can be an increased predictor of being overweight.

  • Hormones. Women can gain weight, particularly in situations like pregnancies, menopause, and oral contraceptives. With the advent of estrogen pills with lower doses, weight gain has not been as risky.

Latest Science-Based Data

1. Joint international consensus statement for ending stigma of obesity

  • Published on: March 4, 2020

  • Abstract: This research focuses on the social stigma faced by people with obesity. It emphasizes that weight stigma can cause physical and psychological harm, and that affected individuals are less likely to receive adequate care. The study calls for education about weight stigma to facilitate a new public narrative about obesity, coherent with modern scientific knowledge.

  • Read the full text

2. Causal relationships between obesity and the leading causes of death in women and men

  • Published on: October 1, 2019

  • Abstract: This study investigates the causal implications of obesity traits on non-communicable diseases and explores sex-specific differences in these causal effects. It shows that obesity traits have an etiological role in the majority of the leading global causes of death.

  • Read the full text

3. A comprehensive diagnostic approach to detect underlying causes of obesity in adults

  • Published on: March 1, 2019

  • Abstract: This research emphasizes the importance of adequate diagnostics to detect potential underlying diseases and contributing factors to obesity. It provides practical recommendations to identify diseases such as monogenetic or syndromic obesity, hypothyroidism, and others, as well as common contributing factors like medication and mental factors.

  • Read the full text

4. Genetic and Syndromic Causes of Obesity and its Management

  • Published on: June 1, 2018

  • Abstract: Not available, but this study seems to focus on the genetic and syndromic causes of obesity and discusses their management.

  • Read more


What are the main causes of obesity?

The main causes of obesity include overeating, lack of physical activity, genetic factors, and certain medical conditions.

Can genetics contribute to obesity?

Yes, genetics can play a role in obesity. Certain genes can increase a person’s susceptibility to weight gain.

How does a sedentary lifestyle contribute to obesity?

A sedentary lifestyle, with little physical activity, can lead to weight gain and obesity due to fewer calories being burned.

Are there any psychological factors that contribute to obesity?

Psychological factors such as stress, emotional eating, and certain mental health conditions can contribute to obesity.

Can certain medications cause weight gain and obesity?

Yes, certain medications like antidepressants, corticosteroids, and antipsychotics may lead to weight gain and contribute to obesity.


Obesity is a big problem in today’s society. It’s not just about eating too much. Our article, “What Are the Causes of Obesity,” looks at why people become overweight. There are many reasons, including not moving enough, eating unhealthy foods, genetics, and where we live.

We take a fun look at obesity causes. Imagine at a buffet, thinking about why people get obese. It’s not just the desserts or fried chicken.

Our article explains how watching too much TV and sitting a lot can make us fat. We also talk about how junk food and sugary drinks are bad for our waistlines.

But it’s not all bad news. We look at how some people are more likely to be overweight because of their genes. We also consider how ads for unhealthy food and not having good food options nearby can affect us.

Our article answers the question, “What are the causes of obesity?” We share funny stories and help understand why more people are obese now.

We encourage you to share this article with everyone. Let’s help others make better food and exercise choices. Knowing why obesity happens can help us all live healthier. So, read our article and join us in fighting obesity!