However, there are cut-off values that have to be taken into account when using BMI. This is especially true when used to calculate the BMI of a large number of people.
Adolescents and children vary in height and weight, and so this throws off the calculation of the average normal weight range. This is because their bodies are still developing. Therefore, the cut-off values for them are age- and gender-specific, especially for kids and teens who are below 19 years old.
Does it really work?
While the body mass index is popular and widely-used, there are still a lot of arguments surrounding it. For one thing, it does not always take into account whether the person is muscular. A physically fit person with a good amount of muscle may be confused by the BMI calculator. This is because BMI does not distinguish between fat and muscle.
Let us compare.
A bodybuilder who is 221 lbs and 6 ft. tall will have a BMI of 28. A person who doesn’t exercise weighs 203 lbs and is 6 ft. tall, and he will have a BMI of 27. So a bodybuilder may be deemed as overweight or obese because of their height to weight ratio. While their heights are the same and their weight is similar, they will not be of the same health. Therefore, there are times that BMI is not accurate.
While it is possible to be healthy and overweight, being overweight or obese still holds more risk to certain illnesses and conditions.
Other than the fat to muscle ratio being unclear when it comes to body mass index, BMI also cannot distinguish whether a person is healthy or not.
While it is possible to be healthy and overweight, being overweight still holds more risk to certain illnesses and conditions.
Additionally, BMI can over- or underestimate adiposity. For instance, one study showed that women who had a spinal cord injury and used the BMI calculation found that it had limited use for them. That is because BMI underestimated adiposity for women with their injury.
Another point to note is that the body mass index may not be as helpful when determining what the normal weight to height ratio is for different races and ethnic groups. For instance, some people of Asian ethnicity tend to have smaller frames than Western people. So, a slim Asian woman may be deemed as underweight, despite being healthy and normal.