What is Obesity?    

Obesity is when excess fat is stored in adipose tissue resulting in an increase in weight and clusters of health problems like diabetes, cancer, and heart diseases. Mostly high intake of calories gives rise to obesity. Calculating BMI, skinfold test, waist to hip comparison, and screening test are ways to diagnose obesity. 

Obesity and Overweight

Obesity and overweight are two terms that have been used interchangeably, but these terms' meanings differ from each other. Overweight is a condition when someone has more weight than the weight that is considered healthy at his height and age while in obesity, people have more fat accumulation than overweight people.  


If the BMI rate of adults is between 18.5 to 24.9, they are considered healthy person. However, if the BMI rate is 25 to 29.9, then that person's weight is considered overweight, and the person with have BMI over 35 is considered obese. This is because of obese face more disease problems than a weighed person.

There is some similarity between obesity and overweight, both result in the gain of body fat.

Obesity Diagnosis


BMI stands for body mass index. BMI is the ratio of weight to the height of the person. BMI is an important parameter in the detection of obesity. By calculating a person's body mass index, the person could be identified as Obese.

BMI classification for adults (20 or above 20 years old)

Body Mass Index(BMI)                 Class
18 or less than 18Underweight
18.5 to 25Normal weight
25 to 30Overweight
30 to 35Class one obesity
35 to 40Class two obesity
40 or more than 40Class three obesity (severe obesity)

BMI classification for children and teenagers.

The percentage range of BMI    Class
Less than 5%Underweight
5% to 85%Normal weight
85% to 95%Overweight
95%or more than 95%Obesity

Skinfold test

This test is done with the help of a device known as a caliper device. This device is used to measure skin fat by pulling away the skin to measure the width of fat tissue.

Waist to hip comparison

The ratio of two physical features, that is, the waist to hip comparison helps determine if the person is obese. The ratio of waist circumference to hip circumference is measured to obtain the results.

Cause of Obesity

Wrong Food Habits 

It is an old saying that "You are what you eat." Therefore, food makes life healthy and beautiful if the person eats whatever the body needs. But nowadays people prefer food according to the taste choices and not according to their body requirement, which leads to wrong food habits. Moreover, junk food contains high calories and high fats, which increase risk factors associated with obesity.

Overeating: It has been observed that people who consume a large portion of food even if their body does not require, then that person has more chance to become obese because the large portion of food contains a large amount of calorie which the body is not able to burn and that calorie is stored as body fat which results in overweight.

Eating processed food: Highly processed food contains a lot of saturated fat or sugar. Saturated fats and sugar contain high levels of calories that store in body fat and result in overweight. 

Absence of Physical Activity

Workout or exercise must be included in the daily activities. Exercising helps the body to burn out calories, which results in weight loss. Conversely, people who do not exercise properly are at a higher risk of developing obesity.


Some genes do not allow a person's body for weight loss; due to this, there is more chance that obese parent's offspring also suffer from obesity.


In type 2-diabetes, insulin resistance stops glucose from entering cells, increasing blood sugar levels. The extra sugar is converted into fatty acid stored as fat in adipose tissue, which results in overweight and obesity.

Hormone Imbalance

Due to hormone imbalance, obese people have a hormone that leads to fat tissue collection, which results in overweight and does not promote weight loss. In addition, Cushing syndrome and hypothyroidism are some diseases that occur due to hormone imbalance.

Cushing syndrome:  High level of cortisol does not allow weight loss. Cushing syndrome results in an increased level of cortisol that affects irregular fat distribution in the body.

Hypothyroidism: Thyroid hormone controls glucose metabolism and fat oxidation. In hypothyroidism, thyroid glands do not produce the right amount of thyroid hormone, which results in disturbance in glucose metabolism and fat oxidation; this results in obesity Hypothyroidism makes it difficult for people to lose weight.

Types of Obesity

There are three types of obesity:

1. Type one obesity: When a person has a body mass index (BMI) between 30 to 35 results in type one obesity. It is mainly caused by overeating and extra food intake.

2. Type two obesity: When a person has a body mass index (BMI) between 35 to 40 results in type two obesity. It is caused due to diseases like Cushing syndrome, hypothyroidism, and other diseases.

3. Type three obesity: In type-3 obesity, BMI is 40 or more than 40. It is the most dangerous type of obesity that leads to kidney failure, liver failure, heart attack, and cancer. Type three obesity is severe obesity. 

Problems Faced by Obese Individuals

Due to obesity, obese people face health problem many problems. These are the following diseases.

  • Type 2- diabetes: Obese people mostly develop diabetes. It has been observed that obese people have more body fat, leading to insulin resistance, which results in type 2 diabetes. So, weight loss is helpful in diabetes.
  • Cardiovascular diseases:  Overweight people have large amounts of fat cells. Fats cells are large and have no or less room for oxygen due to this overweight result in more blood supply throughout the body. This results in high blood pressure, and high blood pressure can cause cardiovascular diseases like heart disease and problems related to blood vessels.
  • Cancer: Overweight increases the risk of several cancers, including breast, urine, kidney and colorectal, and pancreatic cancer.
  • Sleep apnea: Sleep apnea is a condition in which a person faces breathing problems during sleeping. Heavy snoring is one of the symptoms of sleep apnea. Sleep apnea is one of the major risk factors caused by obesity.

Solutions for Obese Individuals

  • Adding physical activity to their daily routine helpful for obese to burn their extra calories so that they can lose their extra body fat and gain a healthy weight.
  • Follow good food habits and lifestyle: For obese, weight loss is a very important task. They can easily succeed in their task by following good food habits, including intake of the right amount of calories and cutting processed sugar from their diet. Eating food on time and taking proper sleep reduces the risk factors of obesity. In addition, controlling their intake of alcohol. Following good food habits help maintain a good healthy weight.
  • Regular check-ups: Checking weight, diabetes, BMI ratio, and waist to hip ratio can help track the health problems of obesity.
  • Meditation: Stress promotes psychological problems and endocrine problems that are one of the reasons for being overweight. Meditation is helpful to reduce stress which helps maintain hormone balance that can help overcome problems related to overweight. Meditation is also helpful to overcome sleep apnea.

Context and Applications

This topic is significant in the professional exams for both undergraduate and graduate courses, especially for Bachelor and Master of Science (Biology).

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