There are three metamorphosis you can take with your body, at least as far as I can tell.
The most common in the US, and maybe the world, is gaining weight. All you need to do to achieve this is eat lots of food. That’s pretty much it, exercise doesn’t really matter. Active or no, eating lots will likely lead to fat gain outside of extreme lifestyles.
The second, which I feel is fairly simple but I understand it is tough for some folks is weight loss. To achieve this you need to eat less. Again, exercise doesn’t really matter here. You will not work out enough to counter a #1 at McDonalds.
Finally we get to what I’m stuck at and arguably the hardest. At least as far as I can tell. Muscle gain. You need to eat some amount of food that I have yet divined. Then you also need to work out the muscles of interest regularly and presumably on the same days as you eat right. Then you’ve to make sure not to stop working out until enough time has passed in the routine to lead to growth.
I’m going to research this soon. It’s something I’ve failed at my while life. Especially now with sore bones and weak joints it becomes an interesting challenge.
If I succeed I’ll write up what I did and why. Because if I can do it, anyone can. I make this assumption on top of the assumption that I’m average which means that on average it’ll be doable.