Your Body Mass Index (BMI) is an objective standard that is becoming the measurement of choice for most health care professionals. It is basically the relationship between your height and weight.
Although Body Mass Index does not directly measure percent of body fat, higher BMIs are usually associated with an increase in body fat and the potential health risks of excess weight. Higher BMIs are an indication of preventable risk just like high blood pressure and high cholesterol levels.
There are some drawbacks to using this index as a measurement of obesity. The BMI makes no distinction between fat and muscle mass. The BMI:
1. Is not a direct measure of body fatness.
2. Does not measure lean muscle mass.
3. Does not show the location of body fat distribution.
4. Does not differentiate between people with small frames and people with large frames. People with stockier builds may be considered overweight without having a lot of body fat. People with small frames may be considered a healthy weight when they actually have an unhealthy level of body fat.
Therefore, BMI is not recommended for use as the sole measurement of either body composition or level of fitness.
That said, the federal government announced guidelines which create a new definition of unhealthy weight: Those individuals with a BMI range of 25 or more with a waist size of over 40 inches for men and 35 inches for women, are considered to be at high risk for health problems–generally, the higher the BMI and the larger the waist measurement, the greater the health risks.
How did Americans get so "hefty?" In my opinion, lifestyle, fast/processed food, snacks, and government subsidies. Food is bargain-priced, plentiful, processed, and mostly unhealthy. I believe our corner eateries, school lunches, and food industries make up a junk food delivery system that is unsurpassed in the world, often serving food that is cheap because it is subsidized by the federal government.
Add a lifestyle that seems to include less and less exercise every year–and–we get fat!
One variable BMI fails to consider, however, is lean body mass. It is possible for a healthy, muscular individual with very low body fat to be classified obese using the BMI formula. If this describes you, ignore the Body-Mass Index.
Below 20: You are considered underweight and may have immunity problems.
20 through 24: A BMI between 20 and 22 indicates a healthy amount of body fat and is associated with a long life and with less serious illness. In fact, through 24 is generally considered satisfactory and indicitive of continued good health.
25 through 30: You are considered overweight and thought to be at increased risk for a variety of illnesses. Time to lose weight by changing your diet and exercising more.
Over 30: This indicates an unhealthy weight where you are at risk for heart disease, diabetes, high blood pressure, gall bladder disease, and some cancers. You should definitely lose weight by changing your diet and exercising more.
To use the table, find the appropriate height in the left-hand column labeled Height. Move across to a given weight. The number at the top of the column is the BMI at that height and weight. Pounds have been rounded off.