> The first ideal time is first thing in the
>morning on an empty stomach after drinking 16-24 oz of water
>in order to prevent dehydration. When performed at this time
>you burn 300 % more body fat than at any other time in the day
>because your body does not have any glycogen (stored carbs) in
>its system to burn. Therefore it has to go directly into the
>fat stores in order to get the energy necessary to complete
>the activity.
I think for as many 'experts' who say this, there are as many who say it's a fallacy.
I've read that whatever glycogen stores you have in your body are from the day before, so working out on an empty stomach wouldn't mean not using glycogen. Also, some people don't have enough energy to workout as intensely if they do it on an empty stomach, so eating before working out may actually help them burn more overall calories because they can put more energy into their workout, and thus fat as well.
As for what to do first, I personally like to do a long cardio warm-up (12-15 minutes, something like the warm-up to Cardio Kicks, or Kick Max), then do weights, then finish off with the rest of the cardio.
What I've seen Cathe recommend several times is to do whatever you want to work on most first. So if you are interested in muscle/strength building, do weights first. If you are more interested in working on aerobic capacity, do cardio first.
Given this advice, I'm not sure why all of Cathe's workouts are cardio first, then weights (except for the fact that the cardio serves partially as a warm-up to the weights?), but 4DS has premixes that put the weight work first.