You shouldn't be getting truly FAT (15+% BF) if you trust your instincts and have experience with your body.
1. You can't force feed muscle growth; Putting on muscle tissue is uncomfortable, it shouldn't be unbearable. You are going to develop food allergies, gall bladder issues, and major GI problems if you just shovel food in with hopes of it turning into muscle.
2. You need to train your metabolism and body to handle the food volume and calories slowly over time. A 150 lbm guy and a 250 lb lbm have 2 very different caloric requirements.
3. You can utilize compounds like GH and MK 677 to keep you leaner, and stimulate appetite.
It's not just about what you're eating, it's what you are assimilating.
With all this in account, You NEED to be in a caloric surplus to build any appreciable muscle tissue (barring growing into a show through smart PED use, being a genetic freak, and regaining lost muscle tissue).
If you eat clean, and proper most of the time; you really shouldn't be getting very fat. It's guys who miss meals, then make up for it by eating junk food that turn into fat slobs. Or who stare at the scale trying to hit a certain "number". Or natural fatties like little slice (
).
Now this is my view as a naturally skinny/lean guy. A guy who accumulates BF will tell you a different perspective, and a guy who puts on muscle easily, and doesn't get fat won't be posting on bodybuilding forums