One of my older bros was always tall and lanky. Turned out he had to get several teeth/gums drained because they were infected. He didn't have bad breath or anything because it was deep but when the dentist got in there he nearly passed out from the smell and has naturally filled out very quickly since.

Strange how something he didn't even know he had for a long time was able to delay his filling out. Unlike my other bro he just grew up but not out until his teeth were fixed.

Maybe with all the recent improvements you've made with your diet etc you'll find you will naturally fill out over the next year or two and won't need to put much effort into it? Maybe since your body has been recovering from various injuries it has been under a bit of stress recently and it'll fill out more easily soon?