New BMI Calculator

nkl
February 2017

Body Mass Index

The BMI is an attempt to quantify the amount of tissue mass (muscle, fat, and bone) in an individual, and then categorize that person as underweight, normal weight, overweight, or obese based on that score.

The Application

In 2013, researchers at Oxford University have updated the BMI with a new formula which more accurately estimates body fat.

Replacing the conventional BMI formula is one that scales more accurately according to a person's height

\( New BMI = 1.3 * weight(kg)/ height (meter) ^{2.5} \)

This calculator is based on the New BMI formula, based on the user-inputed weight (in kg) and height (in meter).

The Source Code

The source code for the project is available in Github.

First, the user inputs his/her body weight and height.

Weight = 50  ;  Height = 1.60
BMI <- (1.3*Weight)/(Height^2.5)
BMI

[1] 20.07305

Classification of BMI Score

The following function then classifies the new BMI score.

category <- function(Weight, Height) {
  BMI_out <- (1.3*Weight)/(Height^2.5)
  ifelse(BMI_out < 18.5,"Underweight",
         ifelse(BMI_out < 25.0, "Normal Weight",
                ifelse(BMI_out < 30.0,"Overweight",
                       "Obese")))}

For the new BMI score stipulated earlier (50kg, 1.60m), the user is classified as

category(50,1.60)

[1] "Normal Weight"