By default, Wii Fit Plus' UK release uses imperial units (stone and pounds, alongside feet and inches). However, in other releases, especially for European players, the game is in metric, even when set to English on the same disc (since the PAL release is multi language). This patch I worked on (see disclaimer) patches the game's country read function on boot (that copies the system region on boot for the game to select its units) to return Switzerland (code 6C) instead of United Kingdom (code 6E), therefore letting you keep the right country setting on the system while having metric in game.

RFPP01
Wii Fit Plus

Metric units, UK region game
041531B0 3800006C

Also heads up, don't be like me and forget to enable Ocarina patching in USB Loader GX wondering why it is not working.

Disclaimer: I did use an LLM for a decent bit of the heavy lifting sifting through memory addresses and writing the final patch to only affect the exact country read function without messing up other parts of the code (for some reason the first attempt would end up writing to the system's region settings instead of just affecting the game). LLMs were not used to write this post.