This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The concept of obesity has been known since ancient world; however, the current standard definition of obesity was endorsed only about a decade ago.
There is a need for researches to understand multiple approaches to defining obesity and how and why the standard definition was developed.
Since then a new era for weight assessments and search for “healthy” weight started.
In the beginning of 20th century a low body weight was a concern because of threat of pneumonia and tuberculosis especially for young and underweight adults .
In 2001, Food and Drug Administration and National Institutes of Health developed the Healthy People 2010 program that was committed to prevention and treatment of overweight and obesity to reduce chronic diseases associated with diet and weight .
In 2010 report, Healthy People 2010 summarized that the age-adjusted proportion of healthy (body mass index (BMI) ) increased from 23% to 34% for the same period of time .
For example, there is still a question if psychological depression causes obesity or obesity is a cause for psychological depression.
This paper does not declare any perception on obesity and does not aim to cover causes and/or consequences of obesity.
This underscores the extent of the problem and urgency to seek a solution.
Clear understanding of the concept of obesity and its measurements should be the first step for successful research in obesity arena. Even though enormous research has been done to discover the causes of obesity, there is still no clear statement if obesity is exposure or outcome.