I would suggest you leave the carbs out of the pre-workout, and add them to the
post workout drink. This should allow fat to be mobilized during exercise, and at the same time, replace calories with carbs instead of fat post-workout, with an over all effect of preserving muscle and losing fat.
I'm sure you already know this, but your calories throughout the rest of the day are going to make a big difference too.
It depends on your goals really. If you are trying to get big at all costs, you want plenty of carbs in both your pre- and post-workout drink.
If you are trying to grow while leaning out, you will want no carbs in your pre-workout drink, and delayed carbs about 30 minutes after your post workout protein drink.
If you are trying to get lean and keep as much muscle as possible, use only protein pre- and post-workout, then have carbs with your first whole food meal following your workout.
These are just guidelines. There is nothing special about them. You can still get lean with carbs in your pre-and post-workout drink. You can still get big without carbs in your pre- and post-workout drink. Overall calories is still the most important factor and shouldn't be forgotten while nit-picking over subtle physiological mechanisms, etc.
In order to minimize muscle loss during cardio you should treat it just like your other training. Take a pre-cardio protein drink and then follow your cardio immediately with another protein drink.
This may increase amino acid oxidation, but it will spare muscle proteins as well as not interfere with fat mobilization (unlike carbs pre- and post-workout).
And there is some benefit to delaying your carb intake for a while after cardio. This of course is assuming you are trying to lose fat as fast as possible (short term).
The pre-workout protein is still beneficial because it is shuttled to working muscles at a much greater rate than when only taken post-workout, and allows higher intracellular amino acid levels for recovery afterwards.
Fakty, nie mity - stan wiedzy na rok 2003
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