Whoever wants to measure their appropriate body weight takes the help of the body mass index. Also called BMI, this is the most common measurement of a person’s weight and body fat percentage. BMI is closely associated with fitness and weight loss. In fact, those are trying to lose weight and get into better shape are habitual BMI checkers. There are even those who go to the extent of measuring their BMI every single day to see if they have gained or lost weight.

BMI applies to adults above the age of 20. For children and those under the age of 20, BMI percentile is the most appropriate measure of body fat. Keep in mind that BMI is not the direct measurement of body fat. Rather it takes into account the mass and height of a person to calculate the relative size. BMI is related to the indicators of body fat like dual-energy X-ray absorptiometry and underwater weighing. BMI is often used as a method to measure weight and also function as a screening tool to find out weight problems in people. It is considered the safest, easiest, and non invasive method to calculate body fat.

What is BMI used for?

Most commonly BMI is used to determine the healthy weight and body fat percentage of an individual. Even though BMI is not a diagnostic tool, it is a reasonable indicator of healthy weight and body fat percentage in individuals. Because calculating the body mass index is so easy, anyone can perform it to learn about their weight. BMI can also find out weight problems in individuals in a simple and efficient manner.

The BMI measurement used to be known as the Quetelet Index, because it was invented by Belgian mathematician Adolphe Quetelet in 1832. It was changed to “body mass index” by Ancel Keys in 1972. Factors such as age, muscle mass, gender, and ethnicity have no role to play in calculating the BMI. The BMI range is the same for both men and women.

The BMI range is as follows:

  • 5 and lower: Underweight
  • 5 to 24.9: Healthy Weight
  • 25 to 29.9: Overweight
  • 30 and higher: Obese

However, it must be noted that two individuals with the same height and weight may respond to the BMI calculation differently because of variations in body proportions.  BMI is often an accurate calculator of a person’s healthy weight. The BMI score tells if a person is underweight, overweight, obese, or has the healthy weight. If a person is above the BMI range, then there are health risks associated with being overweight or obese.

BMI can be easily measured by using any online calculator or can be manually measured by dividing your weight in kilograms by your height in meters.

BMI in children

Because children are developing and have different body mass at different ages, their BMI cannot be calculated like adults. Instead of index, children’s BMI is measured in percentiles. A child’s age and also their gender is taken into account when calculating their BMI. These percentiles are dependent on the age and gender of the child. This also applies to teens under the age of 20. BMI in children and teens help measure body growth and body fat and if they are within the normal range. The resultant BMI number is converted to a percentile.

The importance of healthy weight

Weight issues are common among both children and adults. These days, childhood obesity is a growing problem. Every one in three children are overweight or obese. Being overweight as a child or teen gives rise to significant health risks in adulthood. Lean children who become overweight or obese as adults either have a medical condition or an unhealthy lifestyle. Having a healthy weight during childhood is also important for heart health. Research has found that people who were overweight as children have 25 percent more risk of developing cardiovascular problems later. Also overweight and obese children have an 80 percent chance of remaining overweight or obese throughout their lives.

BMI Myths

Since BMI is such an easy way to calculate body mass, most people end up believing the wrong things about their BMI results. This has lead to a number of myths floating around about BMI. Although BMI is a fairly reasonable measure of a body fat, it is not always accurate. The following myths should not be believed about your BMI.

Myth #1: A higher BMI means you are fat

Higher body weight can be because of a number of reasons. Aside from body fat it can also be because of muscle mass and water retention. A BMI of 25 or more is usually considered overweight but further examination may reveal that fat is not what is contributing to the weight. Athletes have little body fat but also have a greater BMI because of the muscle mass. Therefore higher BMI does not automatically mean you are fat.

Myth #2: Lower BMI is healthy

A body mass index of 18.5 or lower is considered underweight, while 18.5 to 24.9 is considered healthy. However, a lower BMI does not always mean the person is healthy. It could mean that the person is deficient in essential fat and other nutrients. When the body has insufficient amount of essential fat it leads to a weaker immunity. This is the reason why underweight people are more prone to falling ill. Even though a lower BMI means you don’t have the risk of high blood pressure, cholesterol or cardiovascular diseases, it also means you need to check for deficiencies that could be affecting your health.

Myth #3: Higher BMI increases heart attack risk

It is commonly believed that a higher BMI means the person is overweight, and excess weight is often associated with heart disease. However the BMI is not an accurate measurement of body fat. Even a person with low body fat and higher muscle mass could have their BMI on the higher side. This does not mean they have an increased risk of heart disease. Similarly a person with higher body fat could have a lower BMI and still be at the risk of developing heart diseases.

 Myth #4: Healthy diet and exercise means lower BMI

Although a healthy diet and a proper exercise routine are crucial for maintaining the right weight it doesn’t always mean that the BMI will be low. Muscle mass is often greater than body fat. If your muscle mass is higher, you will have a greater BMI range even if your body fat is low.