Carbohydrates

• Carbohydrates are the best energy source for runners, but only elite runners need ultra-high levels for performance, according to an article by Madelyn H. Fernstrom, Ph.D., on runnersworld.com. Recreational runners, such as those doing the Couch to 5K program, need only about 50 percent of their calories to come from carbs. Excellent sources are fruit and whole-wheat grains, such as wheat pasta or brown rice.
  
  High-carbohydrate foods, especially those that are rich in fiber, will aid you during your runs. Try to have a small amount of carbs either just before or just after your workout. "Carbo-loading" isn't necessary for moderate runners, even those doing Couch to 5K. Therefore, you can skip that pasta dinner the night before and save it for when you're running marathons.
  
  

Protein

• The benefits of protein are twofold: not only does it build and repair muscle after intense workouts, it also does the best job at satisfying hunger. Fernstrom suggests that 25 percent of a runner's diet should be protein, focusing on lean protein sources that have less fat. Options include chicken breast, low-fat dairy products and egg whites or egg substitute.
  
  

Fat

• Fat is an important nutrient for the body, especially a runner. For optimum results eat it in the form of healthy fats and in moderation. Good fats come from vegetables like avocado or olives; nuts, including peanut butter or almonds; and fish oil or salmon.
  
  

What to Drink

• In most cases, plain water is sufficient for new runners. Drink it frequently to combat dehydration, which is a common problem for runners. Consume sports drinks in moderation. While they're effective in replacing nutrients such as electrolytes and decreasing dehydration, sports drinks are also full of sugar.
  
  According to Fernstrom, recreational runners have no metabolic need for sports drinks. If you really want one, she says, stick with a low-calories, low-sugar option such as Propel.
  
  

When to Eat

• In order to know the best time to eat, a new runner needs to listen to their bodies. Some runners eat a small meal before running, while others prefer to run on an empty stomach. Hal Higdon, author of "Marathon: The Ultimate Training Guide," suggests that you should practice eating routines during their training workouts to ensure that certain foods won't upset your stomach during a race.