I'm 180cm (5'11) and 70kg (154 pounds). This puts me at 21.6 on the BMI, which is right in the middle of normal weight.

I have scrawny arms but an average body. Some have suggested that I try aim for 80kg, but that'll put me at 24.7 which is borderline overweight.

What should my diet weight goals be to go from skinny to swole?