You don't drop below your resting metabolic rate, you drop below the level you need to maintain <i>PLUS</i> the weightlifting activity you're preforming. Large shortfalls in calories are counter productive unless it's in a short burst.<p>Also, make sure you're getting enough dietary fat. Many make the change to a low carb diet by just dropping carbs from their low fat diet. You need to up your fat intake because what you were taking in for EFAs previously are now going to be cannibalized for energy instead.