Been working out for 2 years with a strict routine, also did fitness and exercise at college included nutrition ect.
Fast releasing carbohydrates:
Fast releasing carbohydrates give a sudden burst of energy and don't last very long, this is why you see marathon runners eating Jelly Babies (sweets) towards the end and during a race for a sudden burst of energy to lift them up again but but they usually end in a slump.
Types of food:
Banana's
Chocolate
Anything containing sugar
When I work out I have a protein shake 2 - 2.5 hours before my workout
Then depending on how I feel during the workout I'll eat half a bar of chocolate (breaking it into small pieces) a banana or sweets during the workout for an extra boost, but not too much you'll bring it back up
Slow releasing carbohydrates:
Slow releasing carbohydrates supply the body with lasting energy and stamina for a long period of time, usually used for marathons or before sports games, you should eat slow releasing carbohydrates 2 hours before a workout probly best if you're going on a long run or a long endurance workout.
Types of food:
Beans
Rice
Pasta
Potato
Whole grains
Also its important to have carbohydrates and protein after a workout because protein heals your damaged and torn muscles and carbohydrates supply energy to the body which will get the protein to your muscles quicker which makes your muscles grow bigger faster.
Food that contains protein:
Meat
Fish
Eggs
Nuts and Seeds
Protein shakes
Hope that helps abit.