IIhow do steroids magically add more weight

[Bonaparte]

Actual explanation:
1) Much of that weight gain is just water. Either from estrogenic water retention in adipose tissue, or glycogen loading in muscle (glycogen is a large molecule and attracts water, drawing it into muscle cells). This is why we all look bigger on cycle, even if we haven't gained any actual muscle tissue.
2) Increased feed efficiency. Your body absorbs and utilizes more of those macros, rather than excreting them through urine or feces.
3) A lb of fat contains 3500 cals. A lb of lean muscle contains just 500-600 cals (remember that most of it is composed of water, and almost all the rest is protein at just 4 cals per gram).
So if you burn fat while adding muscle (recompositioning), you can gain weight without increasing caloric intake.

[< <Samson> >]

Actual explanation:
1) Much of that weight gain is just water. Either from estrogenic water retention in adipose tissue, or glycogen storage in muscle (glycogen is a large molecule and attracts water, drawing it into muscle cells). This is why we all look bigger on cycle, even if we haven't gained any actual muscle tissue.
2) Increased feed efficiency. Your body absorbs and utilizes more of those macros, rather than excreting them through urine or feces.
3) A lb of fat contains 3500 cals. A lb of lean muscle contains just 500-600 cals (remember that most of it is composed of water, and almost all the rest is protein at just 4 cals per gram).
So if you burn fat while adding muscle (recompositioning), you can gain weight without adding cals.

Deep, all thanks to a quality diet.

With a shit diet, you get just that - shit.