Stomach Issues, Fueling, and Beyond

Stomach Issues, Fueling, and Beyond

Rebecca Youngs, MS, RD, LD

Sports Dietitian, Fit For Life Physical Therapy

Any runner will tell you they’ve experienced “runner trots” or had stomach issues during or after a run. These gastrointestinal (GI) issues are a physiological response to running, so don’t be embarrassed!

The exact cause isn’t known, but when we run, our body shuttles all the blood to our working organs- our lungs and our heart, thus shutting off blood flow to our intestines. Additionally, pre-race nerves, dehydration, a change in hormones, the bouncing around of our stomach and GI system, and sugar-loaded gels could all cause diarrhea. In some cases, dehydration can even leave runners with constipation after a run. Runners who have a high fiber diet (i.e. high fruit, vegetable, and whole grain intake-yes, we want that!), can be more susceptible to diarrhea. In general, there a few tips to follow that could help prevent this from happening:

• Stay hydrated before and during your run
• Eat at least an hour before your run
• Go before you leave the house!
• Focus on calming thoughts, breathing exercises, or even meditation to tame pre-race jitters
• Play with your diet - Is there one food item that causes more bloating, gas, and diarrhea than another?
• Limit high fiber foods 1-3 days before a long run or race
• Limit sugar alcohols (think sugar-free products and items labeled with sorbitol, xylitol, maltitol, etc. They have a laxative effect in some people)
• Choose a gel or energy chew that causes little GI distress (practice, practice, practice!)

If you continue to experience symptoms or they become worse, consult a doctor or consider working with a Registered Dietitian (RD) to nail down a proper fueling plan and identify the root cause of your stomach issues!

When to Fuel:

That dreaded “hitting the wall” feeling during a marathon is due to our body running out of glycogen, the storage form of sugar, that we need to keep us going during a race. When we run, our body relies on that stored glycogen to burn for energy. The idea is to properly fuel during a race before that glycogen runs out. How do we do that? We consume glucose (sugar) that will be stored as glycogen. So, should you fuel and when? 

If you are running a race longer than 1 hour, fueling is recommended based on intensity and speed. The American College of Sports Medicine recommends 30-60g of carbohydrate per hour during exercise >1 hour. If exercise lasts longer than 2.5 hours, 60-90g of carbohydrate per hour should be considered. Always consume a small amount of water with any type of gel, gummy, or energy chew. Another rule of thumb I use it to take a gel/chew every 5-6 miles during a marathon. Some runners will find that they need the fuel every 4-5 miles or can stretch it to 7-8 miles. It all depends on the person, how their stomach handles the sugar, and what is most comfortable for them. 

Choosing the right type of fuel:

From waffles to chews, to gels to drinks, there are various products to use during a run! It can be overwhelming to look through the many packets and tubes, and what works for your training partner may not work for you! Things to consider should be texture, flavor, form, and how you will carry the fuel. Some individuals prefer to drink their fuel, while others like the sensation of chewing! The most important thing is to practice your fueling plan during your training runs!

Popular brands include:

• Clif Shots Blocks/Gels
• Gatorade Chews/Gels
• PowerBar Powergel shots
• Gu Energy Gel
• Huma Gel
• Maurten Gel/Drink Mix
• Honey Stinger Gels/Waffles
• Sport Beans
• UCAN
• SIS

Alternative Forms of Glucose:

• Honey
• Swedish Fish
• Dates
• Pretzels
• Dried Apricots/Dried Fruit
• Jellybeans
• Fruit purees
• Bananas
• Baked potato wedges
• Fig Newtons

Remember, there is no right or wrong product to use! Finding what works for you in terms of taste, GI tolerance, and carrying the fuel during your run or race is all the matters. When in doubt, consult an expert who has knowledge in the products you are considering to find what works for you.