I see this thread popping up a lot and I wanted to give my 2 cents about getting/staying fit as pertains to nutrition.
Protein before and after a workout is CRITICAL to losing fat and gaining muscle. Taking around 10-20 grams of protein 30 minutes before working out helps your blood carry more oxygen, therefore making your stamina last longer. When you are finished working out is is VITAL to have at least 20 grams of protein 30 minutes after. Having lots of carbs after a workout is only going to hinder or slow your progress. Look for a protein that uses whey isolates as they absord and your body can use them to create muscle faster.
This is what I use,
http://www.gnc.com/product/index.jsp...046468.4065346
While gatorade is great for rehydrating avoid it. Instead drink just plain old water and add electrolytes to your water.
You can also take a pre-workout that will boost your energy and focus. I use Jack3d and LOVE it, but may not be right for most people. It makes me run faster, lift heavier and enjoy my workout a lot more. Some people it can make them feel jittery or weird (this is just it opening up your blood vessels). Lastly jacked is not a steriod or anything like that, it is just a caffine boost with other natural additives to help your workout.
If any women are concerned this will not help them stay trim and toned, I have been using this combo for 2 years and I am very toned and strong for my weight (150). It all comes down to reps done (i do 3 sets of 12) and length of workout.
Hopefully I'm not repeating someone else and that someone can find this useful.