When taking on the challenging task of training for a marathon, it's critical to incorporate a solid nutrition plan. In fact, fueling is just as important as the hours spent pounding the pavement. Choosing the right foods and knowing when to fuel can mean the difference between a sub-par race and a PR.
You have boundless options when it comes to fuel type, amount and timing of intake. But these simple tips will help you avoid the most common fueling mishaps.
Avoid Fueling for Runs Fewer Than 2 to 3 Hours
Your body has 2 to 3 hours worth of glycogen stores and plenty of fat. Fueling unnecessarily for shorter workouts can lead to negative effects, such as weight gain and gastrointestinal distress. Delaying dietary carbohydrate intake until necessary promotes the use of storage fat for fuel, which is also referred to as metabolic efficiency.
For runs that are less than 120 minutes, it's usually not necessary to consume calories during the workout. For longer runs that are greater than 120 minutes, fuel can be consumed to promote glycogen replacement and provide energy. Keep in mind that everyone is different; some individuals can easily run 3 hours without fuel. For others, this is too long. Use long training runs to experiment with fuel timing.
Avoid Fueling Last Minute
Last-minute fuel intake 30 to 60 minutes before a training session could potentially create rebound hypoglycemia, which is low-blood sugar due to the insulin response triggered by high-carbohydrate food. This condition can negatively impact energy levels, according to The International Journal of Sports Medicine. If you must fuel right before a training workout, do so in the 5 to 15 minutes before a run or race. It's also good practice to avoid high-glycemic foods during this time frame.
Avoid Fueling Excessively
This concept applies to both training and racing. Although replenishing lost nutrients is a good thing, providing your body with too much energy impedes your ability to use fat for fuel due to insulin response.
Older recommendations found in The Journal of Sports Medicine and The Journal of Sports Sciences total 60 to 90 grams of carbohydrate per hour. This equates to 240 to 360 calories per hour, which increases the possibility of gastrointestinal (GI) distress, according to Medicine & Science in Sports & Exercise. In addition, The International Journal of Sports Nutrition & Exercise Metabolism reported that greater carbohydrate intakes for women competing in an Ironman race actually led to longer finishing times.