Sports is definitely hard to have take off in these sorts of spaces, since sports are generally talked about much more amongst regular/casual users, than the more tech-savvy crowd who are willing to try these things out.
It’s the same on the biggest ActivityPub platform (Mastodon) - the really popular regular subjects such as sports and cars just don’t have a presence there.
Isn’t this literally what Waistline is for Android? You create your own local food database (which you can automatically fetch info from Open Food Facts or USDA if desired, but not required) which lets you put in as many nutriments to track as you wish, all with graphs and information with different timelines.
No clue if there’s anything like this for desktop.