You need carbs to have the energy to have good weightlifting sessions. I mean, you can go a little while doing low-carb, but eventually it'll catch up to you. Carbs aren't inherently bad. It's the kinds of carbs you take in. Carbs from brown rice and quinoa aren't the same as ones from a donut or pizza. Check out the book Bigger, Leaner, Stonger by Mike Matthews. Lots of good workout and nutrition info. Sorry, probably more info than you needed.