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Active Expert: Nancy Clark RD CSSD

3 Posts tagged with the diarrhea tag

Q. Help! What’s the solution to intestinal problems during long runs?


A. Upset stomachs, nausea, cramping, and urgency to take a pit stop are common problems among long distance runners. Because each person has his or her personal response to long runs, I can only ask you lots of questions, but perhaps they will help you find an answer. Here goes...


• Are you running too far, too fast too soon and your body is telling you it isn’t ready for that distance?

• Are you stressed and anxious on long-run days, and your nerves are creating the problem?

• Do you eat too much food the night before? If so, try having your big meal at brunch the day before and eat lighter at night.

• Do you eat too much breakfast before the long run? Try eating part of the breakfast the night before, at bedtime, so you’ll be less hungry in the morning.

• Do you eat fatty, heavy foods (like a sausage, egg ‘n cheese biscuit) before the long run?

• Do you drink too much pre-run coffee?

• What do you use for fuel during the long runs? Gels sometimes cause GI problems. So can commercial sports drinks or candies with the wrong kind of sugar for your gut.

• Are you chewing sugarless gum? The sweetener (sorbitol) can cause GI distress such as gas and diarrhea.

• Do you eat yogurt, kefir, or take probiotics? They can help resolve bowel issues.

• Do you get dehydrated? Lack of fluids contributes to diarrhea.

• Do you eat a high fiber diet? “Healthy” diets with abundant whole grains, fruits and veggies can become problematic for some runners.

• Is the problem limited to during runs or do you have intestinal issues at other times of the day? Perhaps you have latent Irritable Bowel Syndrome that gets aggravated during long runs?

• Do other people in your family have intestinal issues, like constipation, diarrhea, bloating, or colon cancer? Perhaps you have problems digesting gluten (a genetic tendency) and should be tested to see if you have Celiac Disease?

• Have you kept food logs to track potential culprits so you can pinpoint, or at least narrow down, the problem?


Good luck being a food detective! And don’t hesitate to seek medical advice if all of the above suggestions fail to find a solution. A consultation with a local sports dietitian for a nutrition check-up can be very helpful! See for a referral network.


Please add your comments if you have found a solution not mentioned above!

5,202 Views 0 Comments Permalink Tags: running, nancy_clark, pre-exercise_food, diarrhea, constipation, runner's_trots, intestinal_problems_in_runners

When I was starting my career as a dietitian, celiac disease was a rare occurrence. Today, it seems like lots of athletes report they have celiac disease and need to avoid gluten, the protein in wheat that creates health problems. Data suggests about 1% of the population now has celiac. The disease is appearing in countries like Finland where it historically has been very uncommon.


While no one is certain why this is happening, one theory is we are growing wheat that has a higher gluten content (to make a better-textured bread).  For some people, the higher gluten content triggers an aggressive immune response that damages the intestines and generates an inflammatory response that makes the person feels lousy. Some suffer from diarrhea, constipation, bloating, gas, or other gastro-intestinal issues. Others don’t realize they have celiac until they experience iron-deficiency anemia. (When the intestines get damaged from the inflammation, they cannot absorb iron.) Otehrs have stress fractures, due to poor calcium-absorption.


If you have digestion issues and suspect celiac, do NOT go on a gluten-free diet without first talking to your doctor and getting a blood test to rule-out celiac. Otherwise, the absence of gluten in your diet will alter the test results. Skipping the blood test means you might miss out on other problems, like Crohn’s disease, ulcer, or colon cancer.


If you know that eating a gluten-free diet is best for your body, take solace in the fact that fruits, vegetables, beans, lean protein, lowfat dairy foods (milk, yogurt, cheese) are all naturally gluten-free, as are rice, potato, sweet potato, and corn. You might want to try gluten-free products, such as brown rice pasta. There are many options in today’s supermarket, but be cautious: “gluten free” does not always mean “healthier”!


Regards, Nancy


For more information:

1,204 Views 0 Comments Permalink Tags: wheat, nancy_clark, gluten, gluten_free, diarrhea, constipation, celiac, wheat-free

Dreaded diarrhea

Posted by Nancy Clark RD CSSD Feb 3, 2011

Marathoner Bill Rodgers may have been right when he commented more marathons are won or lost at the porta-toilets than they are at the dinner table! Diarrhea is a major concern for many athletes, particularly those who run. Understandably so. Running jostles the intestines, reduces blood flow to the intestines as the body sends more blood to the exercising muscles, stimulates changes in intestinal hormones that hasten transit time, alters absorption rate, and contributes to dehydration-based diarrhea. Add some stress, pre-event jitters, high intensity effort—and it’s no wonder athletes (particularly novices whose bodies are yet unaccustomed to the stress of hard exercise) fret about "runners’ trots."


Exercise—specifically more exercise than your body is accustomed to doing—speeds up GI transit time. (Strength-training also accelerated transit time from an average of 44 hours to 20 hours in healthy, untrained 60-year old men.) As your body adjusts to the exercise, your intestines may resume standard bowel patterns. But not always, as witnessed by the number of experienced runners who carry toilet paper with them while running. (They also know the whereabouts of every public toilet on the route!) Athletes with pre-existing GI conditions, such as irritable bowel or lactose intolerance, commonly deal with runners’ trots.


Solutions for  intestinal rebellion

    To help alleviate undesired pit stops:

--try exercising lightly before a harder workout to help empty your bowels.

--experiment with training at different times of the day.

--if you are a morning runner, drink a warm beverage (tea, coffee, water) to stimulate a bowel movement; then allow time to sit on the toilet to do your business prior to exercising.

--visualize yourself having no intestinal problems. A positive mindset (as opposed to useless fretting) may control the problem.


The following nutrition tips might help you fuel wisely and reduce the symptoms:


1) Eat less high fiber cereal. Fiber increases fecal bulk and movement, thereby reducing transit time. Triathletes with a high fiber intake reported more GI complaints than those with a lower fiber intake.


2) Limit “sugar-free” gum, candies and foods that contain sorbitol, a type of sugar that can cause diarrhea.


3) Keep a food & diarrhea chart to pinpoint food triggers. For a week, eliminate any suspicious foods--excessive  intakes of juice, coffee, fresh or dried fruits, beans, lentils, milk, high fiber breads and cereals, gels, commercial sports foods. Next,  eat a big dose of the suspected food and observe changes in bowel movements. If you stop having diarrhea when you cut out bran cereal, but have a worrisome situation when you eat an extra-large portion, the answer becomes obvious: eat less bran cereal.


4) Learn your personal transit time by eating sesame seeds, corn or beets--foods that can be seen in feces. Because food moves through most people's intestines in 1 to 3 days, the trigger may be a food you ate a few days ago.


5) Stay well hydrated. GI complaints are common in runners who have lost more than 4% of their body weight in sweat. (That's 6 lb. for a 150 lb. athlete.) Runners may think they got diarrhea because of the sports drink they consumed, but the diarrhea might have been related to dehydration.


6) When all else fails, you might want to consult with your doctor about timely use of anti-diarrhea medicine, such as Immodium. Perhaps that will be your saving grace.


The bottom line 

You are not alone with your concerns. Yet, your body is unique and you need to experiment with different food and exercise patterns to find a solution that brings peacefulness to your exercise program.


Eat wisely & exercise well,



Author, Nancy Clark’s Sports Nutrition Guidebook

Workshop leader: Tampa March 4-5

1,463 Views 1 Comments Permalink Tags: nancy_clark, problems, diarrhea, intestinal_distress, pit_stops, bowels, gastro-intestinal

Nancy Clark RD CSSD

Nancy Clark RD CSSD

Member since: Jul 8, 2007

Hi! I specialize in nutrition for exercise, and help active people figure out how to manage food, weight, exercise, energy and enjoyment of eating. Let me know if you have any questions!

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