Let's say the woman eats a pretty crappy diet, and because she lifts, she puts on 15 lbs of muscle and 5lbs of fat in a year- beats putting on 20 lbs of fat.
When I gained 15 lbs by eating to satiation while lifting in the past 6 month, I only gained 5 lbs of muscle (that's being generous), and 10 lbs of fat. Because fat is higher volume, I obviously look fatter. And don't fit in my clothes, of course. I can post a couple of shots if you wish.