Until few months ago was doing LCHF, well over 2k calories a day and still losing weight. Since increasing protein intake (not massively, 2 eggs for breakfast and larger portion of protein at dinner ) have reduced fat and now daily calories about 1800 - 1900 and started to gain slowly.
Seems that the naturally slim simply don't utilise fat well. Feeling a lot more comfortable too, without the overstuffed sensation that was common on LCHF and now get hungry as well.
SlimLizzy where did you learn slim people simply don't utilise fat well? I'd like to read a bit on that.
Going back to your earlier point, on being underweight and liking it; I would urge you to strongly consider gaining a little, to get yourself over the BMI threshold, or thereabouts.
My rationale for that is if you find you lose weight easily, then all that needs to happen is you pick up some sort of tummy lurgy, or a dose of the flu, or whatever, and you could find yourself in trrouble.
I'm also slight, but I eat like several horses. I certain tuck more away than my OH. He often says he can't work out where it all goes. Anyway, we spent a bit of time in SE asia earlier this year. I ate well. I certainly ate more fruit than I would do in UK, and bearing in mind we ate out literally every evening (for 2 months) and spent periods in hotels, as well as our apartmentI still lost a couple of kilos.
OK. It wasn't a huge amount, and whilst there in hot weather and surrounded by masses of small, petite people, I actually didn't feel thin. When I got home, I can't tell you how much I felt the cold (beginning of April), and how my clothes hung off me.
It took me about the same couple of months to get those kilos back..
I'm absolutely suggesting you add a lot of weight, but just to give yourself some manoeuvrability, against a worrying drop.