One can gain fat on keto, sure, the body still happily raises fat reserves when overeating, at least many people surely function like that. My body only can gain fat extremely slowly even if I eat tons of fat and sugar and probably many people gain easer on high-carb than on keto even with similar calories…?
So, gaining fat on keto is possible, sure but you still need very very much extra energy for some extra fat appear. You can’t store fat without that energy.
So it’s quite odd if you don’t even eat like crazy and gain quickly. Gaining quickly is very extreme to me to begin with, as far as I know, people who tried eating really, really much, couldn’t use the food so well so gained little… But we all heard about quick gain so maybe it just happens at extreme overeating or under certain circumstances…?
Still, you don’t eat fat in insane amounts as you say so I can’t imagine how your body could gain fat. It’s probably at least partly water.
Your metabolism had no reason to go bonkers suddenly either…
It’s a good idea to restrict your food choices a bit for a while, you actually want to lose fat right now and for some (like me), that’s zillion times harder than not gaining… I never could slim down with much nuts and cheese, that’s sure. Sweets are probably fine for me unless I get tempted to eat way over satiation but carnivore solved that potential problem. I heard sweeteners may make a mess for some people though.
Not necessarily, be careful with fat if you are like me and love fat and it miraculously always find the way into your life despite trying to keep it “low” since a decade. But the key is choosing satiating, good food. There are less and more fatty options like that, at least for me. But we shouldn’t go leaner than what suits us. I like eating fatty and it’s fine, I just need to avoid the not satiating fats (for me not satiating, they may be perfect for others).
I hope things get better, it’s not fair that you try to do things right, okay food, exercise and still have this… 