Equations:
<1yo Use actual body weight
1-17 years old ('standard'):
  if height < 5ft:
    IBW= (height in cm2 x 1.65)/1000
  if height > 5ft:
    IBW (male) = 39 + (2.27 x height in inches over 5 feet)
    IBW (female) = 42.2 + (2.27 x height in inches over 5 feet)
Methods not implemented yet:
  McLaren: IBW =
    - step1:   x = 50th percentile height for given age
    - step2: IBW = 50th percentile weight for x on weight-for-height scale
  Moore: IBW = weight at percentile x for given age, where x is percentile of height for given age
  BMI: IBW = 50th percentile of BMI for given age x (height in m)^2
  ADA: IBW = 50th percentile of WT for given age
>= 18 years old (Devine equation)
  IBW (male) = 50 + (2.3 x height in inches over 5 feet)
  IBW (female) = 45.5 + (2.3 x height in inches over 5 feet)