Complex carbs consist of long strings of molecules that are not as quickly digested and dispersed into the blood stream. As a result, there is not a dramatic rise and fall of your blood sugar, so the energy-producing effects last longer. This means you will be able to maintain your speed longer, and you will be able to train longer on exercises that increase your speed. Complex carbs are found in foods such as potatoes, pasta, breads, corn and cereal. Some people swear by them, others say they are unnecessary.
Most people don t.
Maybe, but you need to decide if it s worth it. The bad news is that caffeine makes your blood sugar level fluctuate, and it also contains lots of acid that can cause heartburn and stomach problems during your training. But not everyone experiences these problems. You have to check as to how you react. Studies show that two cups are optimum.