What are some things I can do to slow down the damage I'm doing to my body? I like to run long distance but my muscles are melting away, my hair is falling out, my skin isn't looking the best and I take synthroid daily so I'm scared of early osteoporosis.

I'm trying to eat more, but I have to force myself, I know it's an issue... but I don't know what else to do.

What are some bland foods that are healthy, pack a lot of calories/ fat that I can munch on?