In my mid teens, I averaged about 55-56kg. Somehow, I never ended up going beyond that despite being alot older now. I reached my maximum height at about 16, and my average weight was like 56, but since I started keeping track a few months ago it ranged from 54 to 57kg. I've been doing some really grueling deskwork recently, sometimes 13-14 hours a day, and so I barely have time to eat. I've just been scarfing down a few boiled eggs in the evening for "dinner". Anyway, I reached a new all time low weight of 53.4kg last night - at a height of 183cm. As a grown man. That was after a shower too, so I was a little waterlogged. It's possibly lower.

That's a 15.8 BMI. People on reddit say that its a medical emergency, that I'd be too weak to walk, lol. I've had a sub18 BMI my entire life and usually been between 16.5-17.5. Other than being overworked, I feel fine, and I've always had above average energy levels for my age.

tl;dr I'm extremely thin. For the united statesians: I'm just under 6 feet and weigh 118 pounds, but I feel fine.