Some runners pick the right foods to eat the day before and morning of a race and are diligent about taking in fluids during the competition. But many of those same runners don't eat so "smart" in those weeks between races.
Dietary habits can affect performance and, more importantly, overall health. A solid place to start is with the carbohydrates rule! Because runners constantly must "keep the furnace stoked" (you burn about 100 calories per mile run), shoot for a diet that is about 60 percent carbohydrates.
Marathoners have a good reason for devouring big bowls of pasta and chunks of bread the night before they tackle 26.2 miles of running: Carbohydrates, or carbos as endurance athletes like to call them, are the body's primary source of energy. A typical runner's engine runs hot enough to burn fats and protein as well, but the working body prefers to stoke with carbos.
Nutritionists divide carbohydrates into two camps — simple carbohydrates and complex carbohydrates.
Simple carbohydrates
Simple carbohydrates are found in soft drinks, candy bars, and pastries. As a rule, simple carbohydrates aren't the best source of energy because they often bring along a high percentage of fat, like what you find in a dozen donuts, for example.
Simple carbohydrates can also contain a lot of sugar. If a food has large amounts of fat and sugar calories, then that particular source is unlikely to hold any significant amount of vitamins, minerals, or fiber. Nutritionists say that these kinds of foods hold "empty calories."
However, some foods with high sugar content do have plenty to offer in the way of minerals or vitamins. Certain fruits — such as bananas, oranges, apples, and raisins — break down into fructose (a natural fruit sugar) but are good carbohydrate sources. These kinds of fruits are better snack choices than fat-laden foods such as candy bars.
Some athletes believe that honey — because it's more natural — has more nutritional merit than refined white sugar. But honey, maple syrup, and sugar (brown or white) are all equally lacking in terms of vitamins or minerals. Brown sugar, however, does have a small amount of calcium.
Complex carbohydrates
Good sources of complex carbohydrates include grains, breads, vegetables, and beans. These foods take longer to convert to glucose (sugars) and are then stored as glycogen (stored dietary sugars) in the muscles or liver, to be used for energy when called upon during physical activity.
Runners typically eat a lot of carbohydrates, but it's still easy to run low on the body's best fuel source. As we mentioned, runners burn up around 100 calories per mile. If you are training for a 10-K, half-marathon, or marathon and running even 30 to 40 miles per week in preparation, then you are burning a lot of calories.
A "trained" muscle can store more glycogen than an "untrained" muscle — in some cases, 50 percent more. So if you run consistently, your muscles will learn to store more energy. The more glycogen the muscles can store, the longer they can perform.
To keep up with the calories burned, a runner who weighs 150 pounds needs to take in somewhere between 2,500 and 5,000 calories per day. Keeping in mind that a runner burns about 100 calories per mile, obviously a professional marathoner training 100 miles per week has bigger needs than the fitness runner logging 30 miles per week.
The trick is to limit (but not eliminate) the number of fat calories in your daily diet.