Why is it so hard to gain weight?

Every body is different, either it's very easy or not really. It could be your metabolism, but the best person you could probably ask is your doctor. I, myself, find it very difficult to actually lose weight. It was easy to put the weight on but that's just my body. As I said, every body is different.

I know this might sound pain in the ass, but you need to start weighing your food depending on your weight. you do want the healthiest way possible right? not just gain fat..

I'd advise you to add more protein shakes and I'm not talking about the powder, fuck that^^ just make it yourself at home.

There can be some factors that might make you underweight e.g. smoking, having too little sleep, work out routine that targets wrong areas, eating unhealthy or any other thing that messes up metabolism. But it also might be simply genetics and then there's little you can do about it. Hopefully you find a solution that works for you!

There’s a massive tapeworm inside your digestive track that steals all the calories and nutrients from all the food you eat by consuming the remaining food particles that travel throughout

It's called McDonald's. They'll fatten you up in no time