Nutrition For The Modern Athlete
Updated: Jul 13, 2021
Whether you're a decorated Olympian, professional athlete, or weekend warrior taking breaks from dad-life in the local crossfit gym - every athlete deserves to perform at their full potential.
But a simple Google of "sports nutrition" could send you a thousand different ways. And for a good reason. There's simply no one-size-fits-all approach to sport dietetics.
What any athlete requires nutritionally to improve their performance depends on a variety of factors such as gender, age, body-weight status for their sport, current dietary and lifestyle patterns, climate conditions, type of activity and where they currently reside in their season. Regardless of these specifics however, it’s important all athletes take into account two careful considerations: the nutrient density of their diet (the quantity of each macronutrient needed), and the timing of that nutrition (frequency of meals and snacks in a day).
So let's jump into it. What role does nutrition play in athletic performance anyhow?
"Performance Nutrition" is simply the concept of using food and fluids to enhance training and performance, speed up recovery and healing, prevent injury, and improve body composition.
We'll move through these in chronological order, starting first with nutrition for enhanced training and performance.
Enhancing training and performance:
Optimal Energy Intake:
An athlete's resting metabolic rate (or RMR), the amount of calories burned at rest, is best calculated using a metabolic cart to accurately decipher the amount of O2 consumed and CO2 produced by the individual. But since the majority of us don’t have regular access to pricey medical devices, we can form an educated estimate using the Harris-Benedict equation:
Women: BMR = 65 + (4.35 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)
Men: BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) – (6.8 x age in years)
Keep in mind these estimates don't account for additional calories burned through digestive metabolism (also known as the thermic effect of food), cognitive exertion, healing, temperature regulation or other means of bodily energy use beyond basic organ maintenance. So if they look a little low, take that information with a grain of salt.
With that said, it's time to consider an appropriate activity factor to account for calories burned during exercise.
For light exercise/sports 1-3 days/week: RMR x 1.375
For moderate exercise/sports 3-5 days/week: RMR x 1.55
For hard exercise/sports 6-7 days/week: RMR x 1.725
For very intense exercise/sports 7 days/week or 2-a-day workouts: RMR x 1.9
Now that we have those energy needs pinned down, let's take a look at how we can break up those calories into macronutrient ratios that will best serve the competitor.
Macronutrient Recommendations for Athletes:
In order to properly restore glycogen levels on a daily basis (a form of stored energy utilized in exercise) an athlete should consume between 6-10 grams of carbohydrates per kilogram of body weight each day. Don't know your weight in kilograms? Simply divide your weight in pounds by 2.2. For example, a 154 pound athlete (154/2.2 = 70 kgs) would need 420-700 grams of carbs per day. Now obviously that’s a big range - so lets break it down by sport here.
Strength and power athletes: 6-7g carbs per kg body weight
Endurance athletes: 7-10g carbs per kg body weight
Ultra-endurance athletes: may need 10-12g carbs per kg body weight
However, some elite trained endurance athletes may sustain on lower amounts (3-5g carbs per kg). This might be due to weight loss efforts, or because of the research suggesting that training on decreased glycogen stores may induce gene expressions that increase training adaptations such as burning fat for fuel. However, some individuals are responders to this low-carb fat-burning adaptation, and others are not. The catch is, it takes the body an average of two months to reveal how any one competitor may fare. So if training on lower carbs is something you'd like to try out, be sure to arrange that test-drive for the off-season.
"But wait, what's the worst that could go wrong?"
While low-carbs diets may not compromise performance according to the limited research we have on the subject, they do tend to increase the ratings perceived exertion (RPE) amongst athletes giving starch-restriction a go. Meaning on a low-carb diet, training at a seven feels like you're training at a ten. This is how we tell if someone is responding well to a low-carb diet and successfully transitioning to burning fat for fuel, or if they are simply not a good candidate for skimping on the grains. If RPE increases overtime and actual performance exertion remains the same, it's time to ditch the low-carb train.
It's no secret that athletes require extra protein in order to replenish those amino acids used up for energy, promote the synthesis of oxidative enzymes/mitochondria, prevent sport's anemia, and account for losses during exercise (in sweat, urine, and the GI tract). In fact, most athletes need about 20 additional grams of protein per day compared to normal individuals. But what about individual variability? How can an Olympic swimmer and a weekend gym-rat be expected to thrive off of an identical recommendation?
Since you asked, let's take a look at the optimal protein intake levels for each style of physical activity.
Optimal Protein Intake Levels (per day):
0.8g per kg body weight for a sedentary individual
1.1-1.4g per kg body weight for aerobic endurance athletes or strength-trained athletes looking to maintain their current muscle mass.