Low-Carb (T-Dawg) Diets and Gaining Size?

I just did the Fat Fast to quickly lose some fat (went from 24% BF to 20%BF, 200lb to 180 lb) and now I figure I’ll segue into the T-Dawg for a while to work off some more. Thing is, I know this goes against the whole “you can’t gain mass while losing weight” concept, but can I expect to make any gains while on this? I know I need to drop some more BF, but I’m also really itchin’ to gain some more lean body mass. I think I dropped too much muscle accidentally during the FF and I want to pick it back up, so I was just curious what the opinions are of gains on a low carb diet. Thanks!