Simple carbohydrates, on the other hand, should be limited. Ranging from candy and cookies to sugary beverages and juices, simple carbs are broken down and absorbed quickly by the body. They provide an initial burst of energy for 30 to 60 minutes, but are digested so quickly they can result in a slump afterward.
You should also avoid alcohol and caffeine. Alcohol is a depressant and can reduce your energy levels, while caffeine usually provides an initial two-hour energy burst, followed by a crash.