Physical demands from a 10 mile run requires planning your nutrition to maintain energy stores in the body before, during and upon completion of your run. Determining the amount of calories to eat begins with understanding your personal calorie expenditure during the run.
Basal metabolic rate is the calorie amount burned in a 24 hour period at sedentary levels. Your basal metabolic rate is a factor in calorie expenditure while running. Higher basal metabolic rate amounts result in greater calorie burn while running. A 200-pound man who possesses a higher basal metabolic rate due to a more muscular build, height or youth will burn more calories on the same run as a 200-pound man with a lower BMR.
Net Calorie Expenditure
Net calorie burn is the amount of calories expended during a run minus your basal metabolic rate. For example, if you burned 450 calories on a 60 minute run and your basal metabolic rate expends an hourly rate of 80 calories, the net calorie burn for the run is 370 calories. Net calorie burn is known as the true measurement of calorie expenditure for running. Net running calories equals body weight in pounds multiplied by 0.63 multiplied by the distance in miles. Total running calories equals body weight in pounds multiplied by 0.75 multiplied by the distance in miles. These numbers provide calories burned per mile. Thus, if you weigh 180 pounds, you'd have a net burn of approximately 117 calories and a total burn of around 135 calories per mile that you run. Using these numbers, a 10 mile run would require approximately 1,350 calories.
Bulking up on your calorie intake should begin at least 24 hours before you run. Runners who plan a 10 mile run should eat a variety of complex carbohydrates such as sweet potatoes, brown rice or whole grain breads. These slow releasing energy foods provide energy to fuel the body during a run. Healthy fats that are higher in calories, such as peanut butter, also aid in energy use. If you find your energy levels dropping, eat a snack of carbohydrates and fats such as a banana or trail mix. You should also eat a light snack or meal after running to refuel your muscles.