The Importance Of Gut Health In Athletes

More marathons are won or lost in the potable toilets than at the dinner table.

Bill Rodgers

Has your race been effected by a situation similar to Bill Roger’s quote above? Maybe not to the point where you were in the Porta Potty (if there was one) but maybe due to gas, bloating, etc? Chances are that at some point GI troubles have effected your athletic performance in one way or another. The key to preventing these troubles is to understand what might be happening in your gut when you exercise. In this article I cover some of the more common GI issues based on a talk by Dr. Tommy Wood at AHS 18 and provide some suggestions for avoiding any GI issues during exercise of racing.

There are several aspects of an athletes lifestyle that puts additional stress on the gut. GI issues can be caused by several factors

  • A large caloric deficit due to the amount of energy expended
  • A large volume of food intake
  • Exercise in of itself weakens the gut

As you can see this can be quite complicated. Eating too little food or eating too much food can both cause GI issues. At the same time, the fact that you are exercising is weakening the gut making you more susceptible to GI issues. Furthermore, if you have GI symptoms while at rest then you are very likely to have GI issues while exercising. It seems like a “no win” situation if you are an athlete.

Why would an excessive caloric deficit cause GI issues? Here is a quote from a study done on the results of the Low Energy Availability in Females Questionnaire (LEAF-Q) given to female endurance athletes at the 2016 Rio Olympics. As you can see a severe caloric deficit causes a weakening of the mucosal lining of the gut.

Gastrointestinal problems are commonly reported in female
endurance athletes and in patients with DE/ED.
In this group of female endurance athletes, the variable for gastrointestinal problems was verified by lower current EA. Persistent energy deficiency causes mucosal atrophy characterised by diminished intestinal function as well as morphological changes, linking lower current EA to gastrointestinal

The obvious solution to this problem is to them eat more food, but this also is an issue. Eating the proper amount of food based on your energy expenditure is essential for health and performance. The issue though is that we did not evolve to consume this amount of food. Our guts are not to handling the volume of food required to eat back the calories we burned. When I was training for my Ultra OCR, I was working out 2-3 hours a day more often than not. To replace those calories across a week of training required me to eat upwards of 3500 calories a day 7 days a week. That is a lot of food for our gut to process, especially considering we are doing this in the context of eating a whole foods diet.

Now lets talk about the effect of exercise on the gut.

After the first 10 minutes of exercise at a moderate intensity we start to see blood being diverted away from the gut in order to assist with the exercise we are doing. With the reduced blood flow to the gut we are not able to process any food we might be consuming during or post exercise. Not only does blood flow decrease with time, but also intensity. Even 5 minutes of intense exercise will start to decrease blood flow to the gut.

The decrease in blood flow, and therefore processing of food, can result in either one of two disastrous consequences. Either the food sits in the gut and starts to ferment causing a bunch of gas and bloating, or the food draws in a bunch of water and results in diarrhea. Either one can be disastrous on race day.

What about long term damage to the gut? Well long duration or intense exercise also causes damage to the gut lining making it permeable. What does this mean? This means undigested food particles can then go through the gut lining into your blood stream. THIS IS NOT SUPPOSED TO HAPPEN. The body treats this as it would any other foreign invader that it encounters, it launches an all out attach on these things to eliminate them resulting in inflammation and even sudden food allergies.

Image result for gut permeability

It also works the other way around as well, where blood can enter the gut and will then be found in your stool.

Here is a good example from a study that looked at runners that raced in the Marine Corps Marathon. Out of about 127 people 29 of those people had no blood in their stool before the marathon but tested positive for blood in their stool after.

table 1
In the last row of this table you see 29 people had no blood in their stool before the marathon but tested positive for blood in their stool afterwards.

Eat A Diet The Agrees With You

What is an athlete supposed to do then? The one thing we don’t want to do is to eat food that could exacerbate or inflame the gut because that is only going to make things worse. Processed foods are notoriously bad for us, this includes the gut. The first thing to do is to eliminate processed foods from your diet and eat a whole foods diet instead. This unfortunately might not be enough, as people can often times have sensitivities to whole foods as well. Eating a whole foods diet though is a good first step as it will help eliminate any inflammation caused by process foods and make it easier to identify any other sensitivities. Over time though you should try to eliminate all foods that cause negative reactions in your body in any way.

In addition eating a diet of balanced macronutrients, especially prior to exercise or racing appears to be best for the gut A Keto diet has many advantages, particularly for endurance athletes, however fat can also help assisting in moving endotoxins from the gut across the gut barrier. So eating a nice fatty meal before going and working out is not going to be a good idea.

Being completely reliant on carbs is also not a good idea. If you are too reliant on carbs then you cannot efficiently burn fat requiring you to ingest more calories during longer workouts. This, as we discussed above, is not good for the gut either. In addition to the additional stress place on the gut by not burning fat efficiently, it is also very common to see athletes who have pre-diabetes because of the amount of carbs they ingest, a majority of which are processed and cause inflammation.

Metabolic Flexibility and Fat Adaptation

Being metabolically flexibility and efficiently burning fat can help reduce the burden on your gut during exercise. Metabolic flexibility basically means teaching your body to use both fat and/or carbs in the right situation. We want to use fat as much as possible since it is basically an infinite energy supply, but at the same time utilize carbs when the intensity/duration starts to ramp up. We usually associate “fat adaptation” with a low carb or Keto diet, but that doesn’t mean you can’t eat carbs and be fat adapted. You just need to teach you body to use fat. You can do this with various techniques like fasted workouts, or periodizing your diet so that for certain times of the year you eat low carb and then for other parts of the year you eat at more balanced diet.. Once you obtain that metabolic flexibility though it sticks around as long as you continue to use it and eat a diet that is well balanced when it comes to macros.

How does being fat adapted help with GI issues? Fat adaptation helps in that you should not need to consume as many calories during exercise due to utilizing a higher percentage of fat. This does not mean you should then not eat enough later on in order to replace those calories you expended, it just means you can ease the stress on your gut during exercise due to a lower caloric intake.

What To Eat During Exercise or Race?

In some situations it will be required that you consume food during exercise or a race. I generally recommend athletes start thinking about consuming calories during exercise if they are going to be working out for 2-3 hours. As far as what to eat, I discuss this in another blog post. We want to make it as easy as possible on the gut to utilize the calories we consume. One way to make it easy is to ingest those calories in in liquid form. I discuss my exact fueling strategy which is mainly liquid in the blog post above.

Be Smart About Your Meal Timing

Finally we want to time our meals accordingly. We don’t want to eat big meals to close to our exercise or race due to blood being diverted away from the gut and the possibility of food leaking from the gut due to any intestinal permeability. Give your gut some time to digest food before hand and some time after exercise to give everything some time to settle down. This gives fasted workouts another advantage as you won’t have any food in your gut before you workout. However, fasted workouts are not for everyone. I generally recommend athletes wait at least an hour after eating before working out and wait and hour after working out to eat.

Now that you know more about the importance of your gut for the athlete I hope you can put some of this knowledge to work for you. As always if you need help, reach out and set up a discovery call with me!

1 thought on “The Importance Of Gut Health In Athletes

Leave a Reply

%d bloggers like this:
search previous next tag category expand menu location phone mail time cart zoom edit close