Thank you for sharing. That is very useful to know. I just read in that article that some don't gain weight on those drugs. Definitely I would fall into that category. I rather don't take any pills, as I believe that food is my medicine, but I am always ready to test something out, unless it damages liver, kidneys etc. as quite a few pharmaceutical meds do
I believe in the laws of science, like E=mc². So mass (weight) can't just appear and increase out of nothing. You do need to put in extra energy (kcal) so it can be transformed into weight (kg)
That said, it can however be that certain metabolisms work in such a way that the surplus you eat becomes indeed fat, whereas in others it will get used differently, and not into body mass
Some have candida, fungus or tapeworms etc., that require food (kcal) too. Or when you have ADHD (running all day, more of your food gets dissipated, hence less weightgain, unless you run lots and eat lots). Some lose by having stress, others might gain,
but only if they eat the required amount of surplus kcal
So, if there are 2 similar (size, workout etc) people, who eat the same food all day etc., one can get skinny and the other can gain lots of weight, but only if they eat a surplus amount of food (kcal)
(exceptions are there of course, some claim to live on prana or I read a story that a guru touched a skinny disciple who gained 10 healthy kg overnight
. I loved that story and I wish Sai Baba did that to me. But normally humans must eat sufficient surplus to gain weight as far as I know)
I wish there was a magic pill to gain weight, being so much underweight is not good, but what to do? Probably a severe trauma, I had many, that makes it impossible, and all the ailments I have of course. So, I just have to sit it out
Not that I worry about it, but if I hear something to gain weight, I do check it out