Hydration

• Water is vital to daily functioning and essential for running, as it keeps your body temperature stable in order to allow for proper muscle function. A key indicator of proper hydration is the frequency and color of urination. You should drink enough fluids to use the bathroom once an hour and produce a clear stream of urine. If you wait until you feel thirsty it is likely you are experiencing dehydration. Consume at least eight 8-ounce servings of liquids throughout the day, including water, fruit juice and sports drinks, and limit or avoid alcohol and caffeine.
  
  

Protein

• Protein is essential in repairing muscles after running. Great sources of protein include lean meat, beans, nuts, eggs and supplements, which can come in the form of a gel, powder or a bar. According to active.com, you should eat 1.5 grams of protein for every kilogram of your body weight daily.
  
  

Carbohydrates

• Carbohydrates are a great source of fuel for running. This doesn't mean you should eat loads of pasta before running, but it does mean that your diet should include complex and simple carbohydrates. Complex carbohydrates offer energy that will last longer and be used over a span of time and include such foods as breads, rice, potatoes and pasta. Simple carbohydrates are the quickest-converting form of sugar available and can be found in fruits, which are great as a pre-run snack to get an added boost of energy or after a run to help replenish your energy.
  
  

Quick Tips

• When you feel like you are losing energy, or "hitting the wall," when running it is likely that you are lacking potassium. Eat a banana to restore potassium in your body.
  Iron is also extremely important for a runner, so make sure you get enough from red meat, liver, spinach and supplements.
  A runner's diet should be 20 percent fat, 20 percent protein and 60 percent complex carbohydrates, as noted on active.com.