I gained 25 lbs in 9 months eating at the prime rib buffet 4 times per week, at the same time as I was consuming quite a bit of beer every week at home too. This was at the age of 34-35 when I drove a semi for the Coors Brewery in Colorado. I had plenty of physical labor too, or likely I would have gained even more.
I'm 6'5". In high school I weighed between 150 pounds in 10th grade and 170 lbs as a senior. I used to wear several layers of clothing under my leather jacket to make myself look heavier when I was young and skinny. By my 2nd year in college I was 190 lbs, and by the age of 21, after drinking lots of beer, I was 215 lbs, which lasted until I worked at Coors, then I stayed at 245 lbs until I turned 40. Just watch when your metabolism slows down around or after age 40, as you will then start packing the weight on. Nobody bothered to warn me about my metabolism, and by age 41 I weighed 275 lbs even though I cut way back on intake. Nobody bothered to warn me to watch what I ate when I tried to quit smoking either, and after 7 months off of cigarettes at the age of 44 I weighed 315 lbs. Now at age 52 I am the size of an NFL lineman.
The only way that you can put weight on is if you eat and drink enough and don't use as many calories as you are eating and drinking. So stay away from the gym while you hit the prime rib buffet several times every week and be sure to pound a case of beer per week and soon you will be a lot heavier too. Then you go back to the gym and try to turn all of that flab into muscle!!!
"We stay here, we die here. We've got to keep moving". Trucker Mark