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Obesity

Written by Suchitra Chari
Medically Reviewed by The Medindia Medical Review Team

What is Obesity?

"Few die of hunger. Many die of eating." - Benjamin Franklin

Obesity is a condition in which a person has excess of body fat that could impair health. Obesity increases an individual's risk for various diseases, disabilities, and death.

A paper published in Circulation in 2012, states that "The first law of thermodynamics assures that body weight cannot change if, over a specified time, energy intake and energy expenditure are equal" and hence obesity occurs due to this imbalance of energy between calories consumed and calories expended.

Obesity has, in the recent years become a global phenomenon. This has serious implications, particularly in countries like India, where one fourth of the population is diabetic.


Childhood obesity too has raised grave concerns worldwide as obese children are predisposed to certain health conditions like Type 2 diabetes and cardiovascular diseases.

The obesity facts worldwide are startling -
A large proportion of the world population is overweight. The most acceptable definition of the terms overweight and obesity has been given by The National Institute of Health.

"The terms "overweight" and "obesity" refer to body weight that's greater than what is considered healthy for a certain height".

Fat is a great source of reserve energy for the body. It also acts as an insulator. It is fat that gives the body its smooth contour and its beautiful look.

A normal person has about 30 to 35 billion fat cells. Initially, when a person gains weight, the fat cells grow in their size but later on, if the weight is not controlled the number of fat cells start increasing.

Weight loss results in decrease in size of the cells and not their number. The normal fat cells are 0.4 to 0.6 microgram in weight; the cells of an obese person can weigh as much as 1.2 micrograms.

Genetics, family history, sex and age determine the 'size' of the individual. The rate at which a person metabolizes food and his Basal Metabolic Rate (BMR) are determined by his genetic factors.

Physical inactivity, changes in food habits and lifestyle have been a major reason for the obesity epidemic worldwide.

Obesity has been increasing in low and middle-income countries, as well, where it is more prevalent in the wealthy society. In fully developed countries it is more common in lower-socioeconomic groups.

A conscious effort to alter diet habits and a changed lifestyle are the best methods to manage obesity. For the morbidly obese, prescription pills, non- invasive treatments and weight loss surgeries are also available.

What are the Causes of Obesity?

What are the Symptoms of Obesity?

The patient's appearance and gait are sufficient to arrive at a diagnosis in most cases. Adolescents may experience different symptoms from adults.

The following are the most common symptoms that indicate an adolescent is obese.
The symptoms of obesity may resemble other medical problems or conditions. Psychological disturbances are also very common as well as stress, social pressure and doing developmental chores. Always consult your doctor for a diagnosis.

How can we Diagnose Obesity?

1. Body Mass Index (BMI)

Degree of overweight or obesity can be assessed by measuring height and weight of the individual and thereby calculating BMI.

BMI is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2).

Reference numbers for BMI:
Hence, adults with a BMI of 25 and more are considered overweight while those with a BMI of 30 or higher are considered obese.

Since children and teens are constantly growing, a particular child's BMI has to be calculated against a reference growth chart made for children of the same gender and the same age group. This is called a BMI-for-age percentile.

Reference numbers for BMI-for-age percentile:
Hence, for children and teens of the same age and sex, overweight is defined as a BMI at or above the 85th percentile and below the 95th percentile and obesity is defined as a BMI at or above the 95th percentile.

2. Waist Circumference

A waist size greater than 35 inches for women and greater than 40 inches for men is another way to diagnose obesity. A higher waist size puts them at an increased risk for coronary heart disease and Type 2 diabetes.

What are the Complications of Obesity?

Besides physical discomfort, an obese individual is at a risk of developing diseases such as diabetes, hypertension, cardiovascular diseases, depression, sleep apnea, fatty liver disease, gall bladder disease, osteoarthritis and fertility- related problems.
Obese children are more prone to getting Type 2 diabetes and end up becoming obese adults with all of the above risks.

How is Obesity Treated?

Latest research on the "obesity gene" or the fat mass and obesity associated (FTO) gene concludes that people having this gene respond the same way to weight-reducing techniques including diet, exercise and medications as those not having the gene.

While there could be intrinsic factors that could make a person obese, a strict healthy diet and regular physical activity will help people overcome the problem to a large extent.
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