Why I Became a Performance Nutritionist: Nutrition Mistakes I Made as A College Athlete

What is a Performance Nutritionist?

Performance Nutritionists are specialists in providing nutrition support for athletes. Performance Nutritionists work with professional athletes, Olympic Athletes, NCAA athletes, high school athletes, and lifelong athletes. Many Performance Nutritionists are also called Sports Nutritionists and if they hold the RD credential, they are known as Sports Dietitians.

Performance Nutritionists work with athletes to develop individualized nutrition plans to help them optimize their health and performance. They work with athletes on sports teams, in athletic departments, in hospitals, at physical therapy offices, in eating disorder clinics, in gyms, at schools, in performance centers, and online. 

How to Become a Performance Nutritionist

In the United States, professional organizations (NFL, MLB, MLS), universities, and Olympic teams, require their performance nutritionists to hold the Registered Dietitian credential in addition to advanced science degrees and board certification in sports dietetics.

To be a Registered Dietitian, individuals must obtain a bachelor’s degree in nutrition and dietetics, complete a nutrition residency program (minimum 1200 hours), and pass a national exam. In addition to the basic course work, many Sports Dietitians have master’s degrees in similar fields (nutrition, sports nutrition, exercise science).

To become a Board Certified Specialist in Sports Dietetics, Registered Dietitians must complete an additional board certification, be a Registered Dietitian for a minimum of two years, and complete 2000 hours working in sports. Less than 2% of Registered Dietitians hold this credential. 

Why I Became a Performance Nutritionist

I have been a Registered Dietitian and Performance Nutritionist since 2018. Since then I have worked with well over one thousand Olympic, Professional, and NCAA athletes. As a retired student-athlete turned sports dietitian, I help athletes avoid all the mistakes I made when I was playing. 

When I was playing soccer at school, I never truly prioritized my nutrition. I always loved food but didn’t understand its importance or its impact on my body. This lack of knowledge led to disordered eating behaviors, many hours in the training room, and a torn ACL from the first game of my senior year in college.

In this blog post, I have compiled a list of 4 common mistakes I made as a student-athlete. These fueling issues are ones I still help athletes overcome daily in my sports nutrition coaching program.

I am excited to walk through them with you here to help you understand the importance of nutrition and fueling your body like an athlete!

Nutrition Mistakes I Made as A College Athlete

Skipped post-workout protein and carbs to avoid getting bulky

I don’t know who started this myth but it is time to completely debunk it. Fueling after your workout will NOT result in undesirable body composition or “bulkiness”.

I used to believe this when I was playing. I deliberately skipped post-training or workout fuel to prevent gaining muscle because I thought this would make me bulky.

It is funny now to reflect on this as a Sports Dietitian because one of the purposes of training is to become a more powerful athlete. Optimizing your training results will help you achieve your performance goals. 

How you refuel after a game is a priority and will ensure proper recovery and lean muscle mass maintenance/production. 

The post-workout fueling goal is to replenish your depleted energy stores (glycogen) and help rebuild your lean muscle mass. If you skip post-workout fueling, you’ll break down the muscle tissue, slow the recovery process and miss out on gaining any significant strength.

I waited until “after class” to eat lunch

How often have you thought “I will just wait to eat lunch until after I get out of class” after practice? Maybe practice ran over or you need to run to the athlete academic center to print out the last-minute paper. 

As a busy student-athlete, fueling can get placed on the back burner, especially during the season. I made this mistake all too often. I often prioritized other academic and social activities over eating meals throughout the day.

Student-athletes need to be eating about every 4-6 hours. I recommend 3-4 meals with 1-3 snacks depending on your fueling needs, sport, and goals. By skipping your after-practice meal not only are you hurting recovery (like we talked about before), but you are also setting yourself up for under-fueling throughout the day.

A way to counteract this is to be prepared and plan ahead. If practice runs late and you can’t make it to the dining hall, what snacks do you have in your bag that you can eat on the way to class? Can you pack lunch? A PB&J is another great complete snack option that can stay fresh out of the fridge.

I didn’t realize the importance of water and being hydrated

One of the easiest ways to increase your performance and energy levels is to drink enough water. We are lucky in the United States that clean water is often available and free. So no excuses! Drinking 3-4L of water daily is a way to start seeing performance results immediately.

A fun water bottle goes a long way in helping you stay hydrated. I often send my athletes fun water bottles and they are shocked when they double their water intake. Insulated bottles with straws and fun patterns are a great way to drink enough water.

I didn’t care that I missed my period

My irregular periods started when I was about 15. I noticed that when I would increase my training load or practice time, my periods were lighter and farther apart. Which was nice! And the opposite happened when I wasn’t training as much. This is when I started to make the connection between my training load and my period. 

Unfortunately, I made the wrong connection. I believed that a lighter or absent period meant that I was fit. Since I was training more, I would get positively reinforced by coaches and trainers. I connected that a lighter or no period is a good thing. 

But young Reilly was so wrong! A menstrual (or no menstrual) cycle isn’t a measure of fitness or performance, it’s a measure of energy availability.

When you have an energy imbalance, an irregular menstrual cycle is one of the first noticeable symptoms but there are many other side effects. You will have an increased risk for illness/injury, low heart rate, weak bones, hair loss, undesirable body composition, low energy levels, and poor performance results. 

If this sounds serious, it is because it is! But I’m not here to scare you. I’m here to open your eyes to it and help you realize there is a better way! I struggled with this when I was younger and I want to prevent it from happening to you! Many of these negative effects are reversible when you correct the energy balance.

When you provide your body with the fuel your body needs, you can regain your period and help reverse some of these harmful side effects.


When I was playing Division 1 soccer, I was constantly under-fueled, always hurt, and had poor mental health. I lacked the sports nutrition knowledge and guidance I needed to maximize my performance on the field and life off of it. 

That’s why I became a Sports Dietitian and performance nutritionist! Performance nutritionists are specialists in providing nutrition support for athletes. Many Performance Nutritionists are also called Sports Nutritionists and if they hold the RD credential, they are known as Sports Dietitians.

As a Sports Dietitian, I help athletes avoid underfueling and maximize their performance on the field. In my Performance Fueling Club sports nutrition coaching program, athletes go from under-fueled and confused to confident and energetic on the field. I would love to help you become confident and energetic on the field too!

The Performance Fueling Club is now accepting applications from motivated athletes who are ready to meet their goals on and off the field. Apply today!



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