The Science of Training and Recovery: Why Carbohydrates and Protein Are Key

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Last updated: February 5, 2026

You have probably heard this common phrase, “you can’t out-train a bad diet.” While nutrition plays a key role in overall fitness goals, it goes far beyond fitness aesthetics. How you fuel your body before and after exercise plays a vital role in performance and recovery. There are many opinions surrounding this topic, one being: “fasted workouts are more beneficial.” What many people don’t consider is the research behind the importance of carbohydrates and protein in fueling progress. These macronutrients are essential for:

  • Sustaining overall energy pre and post workout
  • Rebuilding muscle
  • Mental clarity
  • Muscular recovery

No matter what your fitness level is, whether you are an experienced gym goer, or just getting started on your fitness journey, understanding how to properly fuel your body will work wonders in your health, performance, recovery, and results.

What Are Carbohydrates?

Carbs tend to get a bad rap in a portion of the health and fitness world. However, carbohydrates are essential macronutrients for the body. Without them, our body would feel extremely fatigued. They are known as the body’s primary energy source. Carbohydrates are composed of two different sub categories:

  • Simple Carbohydrates: These are digested quickly, and provide quick, sufficient energy to the body. This includes natural sugars such as fruit or honey, and processed sugars such as table sugar.
  • Complex Carbohydrates: These take much longer to be digested, and provide a longer release of energy. Think starches and fiber, such as whole grains, potatoes and beans.

Once we eat and digest these carbohydrates, they are transferred to the bloodstream, where they live in our cells providing our body with energy. Although carbohydrates are the body’s preferred source of energy, we can still break down protein and fat to create energy, just not as efficiently. Glycogen (our body’s stored form of energy), is essential in providing energy to the brain, heart and muscles. 

What is Protein?

If you have ever heard the statement “everything is made up of protein” that’s because it is true! Protein is essential for a large majority of our body’s ability to function. Protein is made up of amino acids, which help muscles, hair, skin, bones, and organs. There are 20 different amino acids that make up different protein structures.

  • 9 of those 20 amino acids are considered “essential” which means we need to obtain them through our diet.
  • 11 of those 20 amino acids are “non-essential” meaning the body already produces them naturally.

Let’s dive deeper into how protein and carbs can impact exercise recovery and performance.

Why Protein and Carbohydrates Matter Before Exercise

Knowing that carbohydrates are our body’s primary source of energy, how do they actually benefit exercise performance? Once the body has digested a source of carbohydrates to their simplest form of sugar, it is transported through the bloodstream where it can be stored in the liver and the muscles. Glycogen (glucose) stores in the muscles are then used for supplying energy during muscular contractions from exercise.

Protein is responsible for muscular recovery and building. Eating protein is most commonly emphasized after exercise, however it can provide a variety of benefits prior to exercise. Protein consumption prior to exercise can initiate the process of muscle protein synthesis, which is what helps to build and repair muscular tissue. Recent research is showing that eating protein prior to a workout can extend the window of time after a workout in which the body absorbs protein to rebuild muscle. This can be beneficial for people who may not be able to make a meal following a workout.

Why Protein and Carbohydrates Matter After Exercise

Exercise causes your muscles to have tiny tears, also known as a breaking down of the muscle. Protein is essential in helping to rebuild and fix those tears, making your muscles stronger overtime! Protein provides the building blocks your muscles need to repair and grow. When eaten together, protein and carbs work even better—carbs help your body absorb protein more efficiently, speeding up recovery. During a workout, your muscles use stored glycogen to perform necessary muscular contractions in order to break down the muscle. It is important to replenish these energy stores after a workout in order to prevent fatigue, sluggishness, and help to prepare your body for the next workout.

When Should You Eat Pre and Post Workout?

When you should eat prior to a workout is partially dependent upon how you feel after a meal. Eating too close to a workout may cause some discomfort, especially as your body is still trying to digest the meal. According to the Academy of Nutrition and Dietetics, a good time frame to eat prior to exercise is between 1 to 4 hours. 

In terms of eating after exercise, as we just discussed, it is important to get protein and carbs following a workout. Current research is showing to consume protein and carbohydrates within an hour after a workout if possible. This is also to prevent post-exercise hypoglycemia, or low blood sugar following exercise. 

Pre and Post Workout Fuel

Now that we have covered how these macronutrients affect exercise, you may be wondering what are some good options for meals surrounding exercise. Let’s take a look at a few options for pre and post workout fuel: 

Pre-workout: 

  • Greek yogurt with fresh fruit and honey
  • Scrambled eggs with sourdough toast or fruit 
  • Banana with peanut butter 
  • Grilled chicken and sweet potato 
  • Energy bar 

Post-workout: 

  • High protein smoothie 
  • Taco bowl (rice, ground beef, bell peppers, and avocado) 
  • Snack plate with fresh fruit, cottage cheese, eggs, and a meat stick 
  • Tuna salad sandwich 

 

References: 

Mohr, C. R. (2019, September 19; reviewed July 23, 2024). Timing your pre- and post-workout nutrition. Academy of Nutrition and Dietetics. Retrieved from https://www.eatright.org/fitness/physical-activity/exercise-nutrition/timing-your-pre-and-post-workout-nutrition

Schoenfeld, B. J., Aragon, A. A., Wilborn, C., Urbina, S. L., & Hayward, S. E. (2017). Pre- versus post-exercise protein intake has similar effects on muscular adaptations. PeerJ, 5, e2825. 

Written By: AZ Dietitians
Published: August 25, 2025

Last updated: February 5, 2026

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