He's probably confusing paleo with VLC. I've read and heard a lot of stories about women, in particular doing a VLC version of paleo on top of hard workouts and ending up with a wrecked metabolism.
For me, I feel better working out when I have carbs. Paleo allows plenty of carbs. If you are doing bootcamps and crossfit and lifting heavy, fortheloveofgod, you can have some good carbs like bananas and sweet potatoes. I think the people who end up fucked up are the ones that do the hard workouts and avoid carbs like the plague, even good ones. There are definitely a lot of paleo and primal people who are super anti-carb though and don't do anyone any favors when they freak out over athletic/active people eating carbs..