Just at the same place as the weight is shown, show the bmi. Body mass index.

It is easy to count on your own..
but I have diferent bmis as part goals. It encurrage me to loose more weight. Like now im satisfied with bmi 29, wich means im not fat anymore, just overweight. Would be happy to see it everytime i put in or check my weight :)

(For those who dont know it is weigth/(length*length) weight in kg and length in meters. 18 to 25 normal 25 to 30 is overweight 30 to35 id obese over 35 is extreme obese.)