been trying to take better care of myself lately and I really appreciate the variety of health and fitness apps out there that help me visualize my progress
It's not the missing numbers in general β that's fine. It's more that 0 (specifically) isn't visible.
It's a very good trick for giving the impression that something is significantly better β or worse β than it really is, which I don't think is what you're intending here.
0 is relevant. It provides a base line; scale becomes clear at a glance. Obviously, I don't expect body mass to fall (close) to 0β¦
(It is true that a few numbers, clearly marked, from a scale proportional to body mass would work, though less obviously so.)