Body Mass Index Application

Made for Developing Data Products - Coursera Course

Alberto Florez

Body Mass Index (BMI)

First published in 1972, its been the standard for body fat measure.
Although not perfect, due to its simplicity its widely used and even recommended by the WHO since 1980.
The BMI is universally expressed in kg/m2, resulting from mass in kilograms and height in meters.
BMI ranges from underweight to obese and is commonly employed among children and adults to predict health outcomes.

Limitations

BMI is proportional to mass and inversely proportional to the square of the height.
Taller individuals tend to have a higher BMI compared to the body fat level, and smaller individuals tend to have narrower normal weight frames.
BMI categories are generally regarded as a satisfactory tool for measuring whether sedentary individuals are underweight, overweight or obese with various exceptions, such as: athletes, children, the elderly, and the infirm.

Some information about the shiny app

The shiny app is a very simple calculator provided with the function

BodyMass <- function(weight, height){
  weight/height^2
}

Also, with avery simple classifier to put given BMI into WHO categories

Categ <- function(x) {
  if (x <= 15) {
    print ("Very severely underweight")
  }
  if (15 < x & x <= 16){
    print ("severely underweight")
  }
  if(16 < x & x <= 18.5){
    print("underweight")
  }
  if (18.5< x & x<= 25){
    print ("Normal (healthy weight)")
    }
  if (25< x & x <= 30){
    print  ("overweight")
  }
  if (30< x & x <= 35){
    print  ("Obese Class I (Moderately obese)")
  }
  if (35< x & x <= 40){
    print  ("Obese Class II (Severely obese)")
  }
  if (40< x ){
    print  ("Obese Class III (Very severely obese)")
  }

}

Example

The user inputs its height and weight (in meters and kilograms) and the BMI and category are automatically calculated by the app.

example <- BodyMass (70, 1.70)
print(example)

## [1] 24.22145

Categ(example)

## [1] "Normal (healthy weight)"