I've always been at the edge of underweight if you look at my BMI, I think I'm presently also a little under what's considered healthy. but so is my father, being skinny just runs in the family, so BMI doesn't count on that, don't feel that weed makes a difference(since it runs in the family, and they don't smoke/vape)
I don't weigh myself often, weight is something I pay no attention to since I can eat what I want without noticing changes in my weight, but I think I'm at something similar as abysmal.
also I'm a small eater, I don't like feeling full so I just eat enough to not feel hungry anymore but never till feeling full, except special ocassions, I do eat very regularly tough(I don't get people skipping breakfast fir example, breakfast is what wakes me up and gets me going in the morning, I don't notice anything from a cup of coffee but breakfast is to me wgat a cup of coffee n the morning is for oher people)
also I don't eat reallu unhealthy, but not especially healthy too. I do have some healthy taste tough, for example I like brown bread(not the just darkbrowncolord but still whitetasting, but just the lightbrown fullgrainbread) but never liked white bread, it's too soggy
also sometimes I get munchies for fruit, and a while ago I switched to mostly drinking water instead of soda/sweetflavored beverages
I suspect I just naturally have a low fat%, if it's a little hot or so I also get very swollen veins on my arms, hands, feet and legs(a friend once joked I would be the perfect heroinaddict since I would never have to search for a vein)
I also noticed that when I'm bored in a hot room I can entertain myself with it, arm down and my veins swell up a lot, arm up above my head and they lie flat again(but still visible)
and eventough I don't work out at all(except driving bicycle for transportation) my muscles are well visible