You can continue to lift while on Atkins, you just need to find a carb level at which you can continue to lift weights.

If you stop lifting, you will lose some muscle mass simply by not using it.

I agree about making sure you eat enough vegetables. You could also try adding in some berries or steel cut oats.

There is a sticky at the top of the Body For Life forum with many helpful threads about combining weight lifting and low carb.

Perhaps all the fiber supplements made gas pains worse. Adding in fiber should happen gradually to allow your body to get used to it. Magnesium can help ease things where fiber seems to make it worse sometimes.

Beth