It's complicated.
Best way to summarize is. I started off as an ectomorph or hardgainer....
Like I developed a decent frame initially. I even put like 20 pounds. Went from 130 to 150lbs at 5'10, when I was 17.....
For the longest time it took me forever to break 160lbs no matter how much I ate or lifted....
Then eventually I realized, If I wanted to pack on size I had to lift and eat a certain....
In mean time, despite all the eating and lifting I did, I wouldnt gain any weight.....
Now my body has a different set point. This is just an equilibrium range where my body feels comfortable trying to maintain a certain weight. So i don't have to eat as much anymore to maintain my size.
With that said. If I stop lifting, I don't gain weight, I just get more shredded. Mesomorphs or endomorphs, when they're my size and they quit lifting, it's over they balloon up....
As far as your metabolism, and eating more, the trick to really gain sizing, is changing how you lift. If you lift right, you'll be hungry as fukk, your body will let you know. And I've never been a big of fan of eating bigger meals, I believe it's more important to eat a balanced diet and get proper rest. Which many people fail to do,
...its amazing i got through my calisthenics workout like i did with all that walking around and not be on some 
shyt
