By Mr. Douglas Holl (USAPHC)September 12, 2019
ABERDEEN PROVING GROUND, Md. -- It may not make for polite conversation, but most runners at one time or another have dealt with unpleasant intestinal rumblings, sometimes called runner's stomach, or faced other gastrointestinal running emergencies while running recreationally or competitively. The Army Public Health Center's resident nutrition experts offer a few strategies to help runners avoid unfortunate GI issues.
"It is difficult to connect the cause and effect of this unfortunate situation, but some plausible culprits are dehydration and heat exposure," said Joanna Reagan, registered dietitian at the Army Public Health Center. "Contributing factors likely include the physical jostling of the organs, decreased blood flow to the intestines, changes in intestinal hormone secretion, increased amount or introduction of a new food, and pre-race anxiety and stress."
Reagan offers a few suggestions to help runners avoid runner's stomach while running or training.
"If you have problems with gas, bloating or occasional diarrhea, then limit high fiber foods the day before you race," said Reagan. "Intestinal bacteria produces gas and it breaks down on fibrous foods. So avoid foods such as beans, whole grains, broccoli or other cruciferous vegetables. Lactose intolerance may also be something to consider, so avoid dairy products, but yogurt or kefir are usually tolerated."
APHC Nutrition Lead Army Maj. Tamara Osgood recommends avoiding sweeteners and sugar alcohols, which can cause a 'laxative effect' and are commonly found in sugar free gum and candies.
"Also, limit alcohol before run days, and try to eat at least 60-90 minutes before a run or consume smaller more frequent meals on long run days," said Osgood.
So broccoli and cauliflower are out. Are there any "good" foods to eat before a planned run?
"In the morning the stress hormone, cortisol, is high," said Reagan. "To change the body from a muscle-breakdown mode to a muscle building mode eat a small breakfast or snack of 200 to 400 calories within an hour of the event. This depends on your personal tolerance and type of activity."
Reagan says some quick food choices are two slices of toast, a bagel or English muffin with peanut butter; banana (with peanut butter); oatmeal, a smoothie, Fig Newtons, or granola bar.
"These food choices will also help provide energy and prevent low blood glucose levels," said Reagan.
Although energy bars and gels are popular, runners who haven't trained with these products may experience diarrhea because of the carbohydrate concentration, said Reagan. A carbohydrate content of more than 10 percent can irritate the stomach. Sport-specific drinks are formulated to be in the optimal range of 5 to 8 percent carbohydrate, and are usually safe for consumption leading up to and during a long run.
Reagan advises staying well hydrated before and during the run and consider getting up earlier than usual to give the GI tract time to "wake up" before the race. For those in race "urges" it's wise to know the race route and where the portable restrooms are located.
Osgood says runners should train like they race to learn how their bodies tolerate different foods.
"Training is the time to understand how your body tolerates the types of food or hydration you are fueling with," said Osgood. "Everyone is different when it comes to long runs regarding the type of foods or best timing to eat for you to avoid GI intolerance. Find out what works for you while you train."
Osgood also recommends refueling following the run. Most studies suggest 3:1 or 4:1 carbohydrate-to-protein ratio within 30 minutes post run.
The Performance Triad website at https://p3.amedd.army.mil/performance-learning-center/nutrition is a good resource for additional nutrition, nutrient timing and hydration recommendations.
The Army Public Health Center focuses on promoting healthy people, communities, animals and workplaces through the prevention of disease, injury and disability of Soldiers, military retirees, their families, veterans, Army civilian employees, and animals through studies, surveys and technical consultations.