Weights Before Cardio or Cardio Before Weights?

Earlier this month, I had lunch with a knowledgeable personal trainer named Brian Johnston who raised a very interesting point with me about how I should structure my workout for maximum efficiency.  Brian argues that I can increase muscle mass and maximize fat burn by engaging in cardio exercise after weight training with kettlebells or other free weights.

As I understand Brian's logic, weight training breaks down muscle fiber, thereby creating a need for a protein source to rebuild the muscle.  Cardio exercise, by contrast, draws on glucose or stored energy.

Brian suggests that after weight training I should immediately sip a high protein drink to feed stressed muscle tissue.  With the body supplied with protein, cardio exercise will tend to draw on glucose (if available) or on stored fat cells.

Michael Siegel suggests a further refinement of Brian's technique as set out at the RealAge website – according to an article entitled "Give Your Workout a Break," the rate at which the body burns fuel can be enhanced by engaging in two 30 minute cardio sessions broken up by a 20 minute gap. 

Michael and I have implemented Brian's tip about the order of our workout and about the use of a high protein drink immediately after the weight training.  I definitely feel less drained after a hard workout and I don't tire as easily later in the day.  I suppose that I might also notice more weight loss if I stopped eating so much, but, after all, Rome was not built in a day.