Capot you are lucky to have your health and your adonis physique, but be aware that neither are guaranteed to last.
15 or so years ago I was borderline skinny, then a change of job resulted in much less physical exercise. Oddly I didn't notice my weight climbing as I rarely bothered the scales as I am not obsessed with looks and have good health. Nor did others point it out.
Today I am about 25 kgs heavier than I was back then. I still fit into an airline seat without too much trouble, and I am happy with my life. If I lose weight fair enough but I am not going to do so just to satisfy others who are so sanctimonious about themselves.
Under your dictat check-in would need to start hours earlier to allow for all the weighing, checking of documents proving weight, and the arguments etc.
I'm with Jarvy on this. Re read this thread and see if you are really proud to be proposing such a bigoted idea.