Why am I not gaining weight?

Why does it matter what I consume and no matter how often, I never gain weight?
I would still like to gain a little weight, since I am below my normal weight.
But I can’t do it.
Could I be suffering without knowing it?​

The reason why you’re not gaining weight is because you’re not in an energy surplus consistently. I don’t say that to be flippant, but that’s the reason. As far as how to resolve that issue, I would need to know more about you and your dietary pattern.