Charge Ryanair passengers by weight

Recently Ryanair announced that they may charge everyone for carry-on luggage.

May I propose that the amount charged is linked to the individual’s BMI, (Body Mass Index). On each flight there would be four weight classes.

First is underweight class which is less than 18.5 BMI, next is normal class 18.5 to 24.9 BMI, then overweight class 25 to 29.9 BMI, and the last is obesity class having a BMI of 30 or more.