I played organized tackle football from age 11-18, I was a receiver and punt returner in highschool 10-12 grades. I was always athletic. That said, I was slim, 5'-7" 155lbs and I could always eat like a horse without gaining weight. I was very strong, though I didn't really know it at the time, that that was how I could handle players much bigger than me.  When I was 23, I wanted to bulk up, so I took up bodybuilding with heavy weights low reps and to gain weight I kept eating like a horse like always, but because I was doing weights, I was hungrier and ate more. Withing 6 months I was at 170 with no fat. I was 44 chest, 30 waist. I was lifting 300lbs on the bench press. I stayed the same weight from there on but got stronger and more defined. I found the best thing to put on weight was Hagen Daz ice cream, it has the highest fat content of any ice cream, and it is outrageously delicious because of the extra fat. The other thing is to take some protein supplement till you are where you want to be. Once you have the muscle you wanted, you will not need the ice cream or the protein but once in a while when you feel you need it.

 

Haagen Das is a bit expensive and I don't wanna give money to Nestle

I played organized tackle football from age 11-18, I was a receiver and punt returner in highschool 10-12 grades. I was always athletic. That said, I was slim, 5'-7" 155lbs and I could always eat like a horse without gaining weight. I was very strong, though I didn't really know it at the time, that that was how I could handle players much bigger than me.  When I was 23, I wanted to bulk up, so I took up bodybuilding with heavy weights low reps and to gain weight I kept eating like a horse like always, but because I was doing weights, I was hungrier and ate more. Withing 6 months I was at 170 with no fat. I was 44 chest, 30 waist. I was lifting 300lbs on the bench press. I stayed the same weight from there on but got stronger and more defined. I found the best thing to put on weight was Hagen Daz ice cream, it has the highest fat content of any ice cream, and it is outrageously delicious because of the extra fat. The other thing is to take some protein supplement till you are where you want to be. Once you have the muscle you wanted, you will not need the ice cream or the protein but once in a while when you feel you need it.

 

90% of all food is controlled by various evil companies, so unless you want to starve to death ...

This is your scruples at work again.

Depends on your metabolism.  I knew some people like you who could eat forever and not put on fat, but then others if they went 100 calories over their BMR would immediately convert it to fat.  I've actually read that you can build muscle even on a calorie deficit provided that you get enough protein, 1 gram per kilo (2.2 pounds) of body weight.

Study I read said that you could gain muscle (with enough protein) even on a 20% calorie deficit.  They had different control groups, and the guys with calories deficit put on as much muscle as the guys with calorie surplus.  Protein is key, and in addition getting all the proper macro- and micro- nutrients that all help in the process.