To wonder what this could be?

[Singasongofsadness]

(Disclaimer: none of my business)

I work with a girl who I started with five months ago but who almost immediately went on sick leave. She's just come back but on a reduced schedule, starting and finishing later. She also often does a four day week or less. It's none of my business but I've noticed shes very slim and doesn't really ever eat much, while going to the gym every day normally. I know I should myob and I do. I'm just wondering whether an eating disorder related illness would necessitate these measures being taken?

Sorry that should say starting later and finishing earlier

Yabu. It isn't your business as you said and it's obvious that steps are being taken. If she wanted to share with you she would do so.

Yes, it's not your business, it's up the the girl and the girl's parents to manage her diet and health.

Unless you are in HR with specific responsibility for youth in the workforce. But as you've asked here, rather than knowing from your role, I suspect that's not the case.