The reason: Things like body weight and workout intensity play major factors. So you're going to have to experiment and find out what works best for your body. Here are a few handy tips to help you along your way.
Before: Go ahead, have some carbs
All those no-carb diets are not great for working out. Carbs are the most efficient fuel source because they break down quickly into smaller sugars that can be used as energy. If you eat a lot of protein right before, your body will prioritize the exercise, which means blood flows away from the digestive system, slowing the process. It also may cause uncomfortable, or even painful, cramps.
Consider your exercise intensity
If you're taking an intense class, you really don't want much in your stomach at all. The goal should be to eat a light, easily digested meal two hours beforehand. Chowing down any closer to the start could cause things like heartburn and other stomach pain and discomfort.
Timing is key
Within 30 minutes of wrapping up your workout, get some food in your belly. That's when the body will be able to use it most efficiently.
Power up after you pump iron
When you lift, you break down muscle fibers. In order to repair and build those muscles back up, you have to feed them with protein. And you'll still want some carbs to boost energy.
Don't overdo it
Giving yourself free rein to eat a massive bowl of soup and a few wraps of pounded yam just because you ran a few miles isn't exactly the smartest decision. You're not getting as much protein and other nutrients as your body needs after your jog. That doesn't mean you shouldn't treat yourself but the old adage rings true; everything in moderation.