Ask The RDN: Fatigue And Diet

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Ask the Sports Dietitian: I feel really tired during training. Could it be my diet? 

A: There are a number of factors – diet and otherwise –  to look at if you’re experiencing persistent fatigue. Persistent fatigue can take many forms, but often it manifests as a deep fatigue with muscle or joint pain, and the inability to recover from training.  The human body is a complex system and if you feel like your diet is generally good, and you generally eat enough, but still lack energy, here are some things to consider.

Energy Intake

We can’t talk about fatigue and not consider a relative energy deficit.  A common mistake among many endurance athletes is not eating enough to support their training volume.  Tuning in to your hunger and fullness cues often and responding to them is critical for adequate fueling.  Sometimes, individuals that have busy schedules need those extra reminders to eat, so setting up a rough eating pattern can help prevent skipping meals and snacks. For instance, scheduling breakfast between 8AM-10AM, lunch 12PM-2PM, an afternoon snack 3PM-4PM, and dinner 5PM-7PM is a good way to do this.   An emergency food stash in your car or at the desk with some healthy pre- and post-workout snacks available can help encourage consistent, healthy fueling. It is hard to generalize just how much food each individual needs, and a sports dietitian can help you dial in the specifics if you’re struggling.

RELATED: Ask The RDN: Rest Day Nutrition

Vitamin or Mineral Deficiencies

Quality is as important as quantity of food. Considerations of the variety of foods you are eating, even if they are high quality is important.  Many people can easily come up short on key minerals like B-vitamins and Iron, which are all heavily involved in the body’s energy production by helping with oxygen utilization.   In order to pinpoint any deficiencies, rather than guessing, seeing a physician for a blood draw or using a service like Inside Tracker can be helpful.


Sleep and stress can also contribute to fatigue.   Not getting enough sleep on a regular basis can affect our hormone levels and ability to adapt to training stimulus. Stress can cause levels of the hormone cortisol to remain high and leave you feeling exhausted. Setting up a set sleep schedule or adding in daily meditation can be helpful in combating these two problems.

Medical Considerations

Having a diagnosed or undiagnosed can also be a consideration in these cases. Because of their inflammatory, damaging effect, conditions that affect the gastrointestinal system like Celiac disease, Crohns, and Colitis affect the bodies’ ability to absorb specific vitamins and minerals.  Hypothyroidism can also cause the body to feel consistently drained because of the lack of production of thyroid hormones needed to help your body produce energy. Symptoms such as abdominal pain, bowel irregularities, nervousness, unexplained weight gain, hair loss, or sensitivity to cold could suggest a serious undiagnosed medical condition,  and merit a trip to your doctor.

One tasty way to make sure you have a nutritious snack on hand?

RELATED: Signs You Might Want To Up Your Protein

On the Go Chocolate Brownie Energy Bites:

Cook Time: 40 Minutes

Serving Size: 12 Bites


2/3c pitted dates

4c black beans (cooked)

1c chocolate protein powder

2/3c sunflower seed butter

1 tsp sea salt

2 tsp cacao powder

1c dark chocolate chips


#1) Line a baking sheet with parchment paper.

#2) Combine dates, black beans, chocolate protein powder, pumpkin seed butter, sea salt, and cacao powder in the bowl of your food processor. Process until smooth.

#3) Roll the dough into 1-inch balls and place on the covered baking sheet.

#4) Chocolate drizzle: Melt the chocolate chips in a double boiler and drizzle over the balls.

#5) Refrigerate at least 1 hour to set.

*Can be stored in an airtight container in the refrigerator for up to a week and in the freezer for up to a month.

Do you have a question for our RDN? Send your trail-running-nutrition quandaries to

Kylee Van Horn is a licensed Sports Registered Dietitian and competitive trail runner.

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