Preparing to run a half marathon starts weeks in advance of the event. A nutrition plan is as important as a mileage plan. Your body must get the right nutrients to perform during daily runs as well as at the big race. Keep junk food to a minimum and focus on whole, fresh foods and ingredients. As long as you balance protein, carbohydrates and fat properly, you have a lot of flexibility in what you can eat.
Endurance athletes need more protein than sedentary people, so their protein intake should be about 0.75 gram of protein for each kilogram of body weight. However, runners should get no more than 30 percent of their energy from protein sources and focus on those low in saturated fat such as lean cuts of meat, tofu, fish, egg whites, low-fat milk and nuts. A chicken breast has about 25 grams of protein, and an egg has 8 grams.
Carbohydrate is your body's main energy source. Runners should get at least 50 percent of their daily calories from complex carbohydrate sources such as vegetables, fruits and whole grains. Processed junk foods such as candy, cookies and sweetened breakfast cereals may seem like a quick source of energy, but they don't contain the beneficial fiber and nutrients found in complex carbohydrates.
The body needs fat to function, and a Colorado State University nutrition handout for athletes indicates that fat may account for up to 75 percent of energy stores burned during endurance events. Runners who log miles training for a half marathon will need to obtain about 20 percent of their daily calories from fat, focusing on nutrient-rich fat sources such as lean meats, fatty seafood, vegetable oil, avocados and nuts.
Drink enough water to keep urine output pale during the day. If it is very hot or you at a high altitude, a diluted sports drink containing electrolytes and carbohydrates can be a good option during workouts. Keep in mind that you can also obtain water by eating fresh vegetables and fruits or other foods that contain a lot of liquid, such as soup.
During the Race
Eat easily digested, complex carbohydrate-rich foods one hour before the race. A banana and a cup of oatmeal or a bagel with peanut butter are popular breakfasts before the typical early-morning start of a half marathon. During the event, consume a high-carbohydrate gel, fruit or a protein/carbohydrate drink every 4 or 5 miles. Drink a half cup of water every mile.