It is difficult to determine the exact percentage of body fat a person has, but estimates can be made in a number of ways.
First, using a tweezer-like tool called a caliper, you can measure the thickness of skin folds on different points of your body and compare the results with standardized numbers. You can also use a small device that sends a harmless electrical current through your body and measures your body fat percentage.
The most commonly used method to determine if a person is obese is to look at his/her Body Mass Index (BMI). A person with a BMI over 30 is considered to be obese, and a BMI over 40 is considered to be severely obese. It’s important to remember though that BMI could be misleading in pregnant or lactating women and in muscular individuals.