The First Step In Mastering Nutrition
This week I wanted to talk about nutrition. As athletes or fitness enthusiast, firefighters or police officers, and trail runners or hikers, if we have goals that require us to stay active, then nutrition is vital to consider. Whether we want to maximize our performance or simply make sure we are doing everything possible to prevent injury, assessing nutrition cannot be skipped. Check out the latest podcast for the audio version of this same topic!
For athletes aiming to optimize performance and prevent injuries through nutrition, the initial step is determining their daily energy requirements for weight maintenance or energy balance. To do this, we need to understand Total energy expenditure (TEE). TEE is the sum of basal metabolic rate (BMR), thermic effect of food (TEF), and thermic effect of activity (TEA). Various factors influence an athlete's TEE, including training, environmental conditions, fat-free mass (FFM), stress, illness, and medications, while energy needs decrease with age.
Basal metabolic rate (BMR) and resting metabolic rate (RMR) are similar, with RMR being more practical to measure. We use this to better understand how much calories we burn simply from normal and vital process in the body. Equations such as the Harris-Benedict equation for BMR and the Mifflin–St Jeor equation for RMR are commonly used. The Mifflin–St Jeor equation incorporates age, sex, height, and weight for calculation. Plug your information into the calculation below to find RMR (find kilograms of body weight by dividing your weight in pounds by 2.2)
-Male=10 × weight (kg) + 6.25 × height (cm) – 5 × age (years) +5
-Female =10 × weight (kg) + 6.25 × height (cm) – 5 × age (years) – 161
After calculating RMR, it is multiplied by your physical activity level (PAL) to estimate TEA. PAL factors range from 1.4 for sedentary individuals to 2.4 or higher for elite athletes. More precisely, PAL of sedentary lifestyle to light activity includes activity like walking or yoga and has a PAL factor of 1.4-1.69. Moderate activity and a PAL of 1.70-1.99 includes fitness classes, weightlifting, running, or cycling. Vigorous activity including endurance and elite athletes has PAL factors of 2.0-2.4 and even higher for elite athletes.
The thermic effect of food (TEF) reflects the energy expended during digestion and may vary based on food types. Eating small, frequent meals is proposed to sustain metabolism, especially during fat loss while preserving lean mass. We can calculate this by multiplying our RMRxPAL number from earlier by .10. Add this number to the RMRxPAL figure. This total is your estimated energy expenditure!
-TEE=RMR(PAL)+TEF
Another important concept to consider is that of energy availability (EA). EA is crucial for exercisers and athletes working hard to maximize performance, with optimal health associated with an EA of 45 kcal per kilogram FFM per day and impairments in bodily functions below 30 kcal per kilogram Fat Free Mass (FFM) per day. Low EA can result from low energy intake, increased activity, disordered eating, or training errors. Having optimal energy availability is allowing the body energy to perform all other functions after the cost of exercise is subtracted. We can find this value by subtracting our total calorie intake from our energy expenditure from physical activity (estimated) and then dividing that by our FFM. FFM by multiplying your body weight in lbs. by your estimated body fat percentage. Then, subtract this number from your total body weight and divide that by 2.2 to get FFM in kilograms. Again, we want the EA number to be at 45 to optimize athleticism and performance. That being said, this value will not be most optimal for optimizing body weight for body composition sports like wrestling or when a goal of exercise is to decrease body fat. Again, EA should not dip below 30 to prevent issue in vital daily bodily functions.
-EA= (total caloric intake-calories lost in physical activity /FFM)
In closing, continuous monitoring of caloric intake and training is essential for adjusting dietary plans accordingly. Once total energy intake is determined, macronutrient needs can be calculated for optimal performance (stay tuned)!
-Dr. Nick, DC
Resources:
-Bytomski JR. Fueling for Performance. Sports Health. 2018;10(1):47-53. doi:10.1177/1941738117743913
