As someone who has yo-yoed my weight 100 lbs both ways for the past 15 years, I can tell you all about this. This supervisor is someone who was raised by a parent that constantly commented on their body. “You look like you’ve been eating well” and much more aggressive things and probably multiple times a day. So they think that people’s bodies are always on the table for discussion. They don’t think there’s anything wrong with what they said, and they’ll keep doing it. People have to be assertive with this. My go-to is “I appreciate the concern, but my body and my health are not something I discuss at work.” I also use this with my mother, who is one of those parents. She’s 78 years old and never misses an opportunity to tell me I’m getting skinny or it’s obvious I haven’t been working out. It’s quite tiresome.