"I gained a lot of weight while I was unemployed."
Translation:İşsizken çok kilo aldım.
kilo kazanmak is rarely used since kazanmak has a positive sense in turkish. it's used when you think gaining weight is a positive thing while it is not necessary in terms of health (e.g. in body building)
what is the difference of usage between ağırlık and kilo? Is ağırlık associated with heaviness like in "this workload is too heavy" context?
Kilo almak is set idiom. And ağırlık aldım=ağırlaştırım would mean treating yourself as a material.