Whether you are a strength athlete trying to make weight, a team athlete attempting to put on size or lean out, or a casual gym goer we all have one thing in common, we all use the same form of energy… calories. But how many calories do we need to maintain our bodyweight? Where do these calories come from? What’s a macronutrient and how many do I need for my individual goals? We will answer all these questions and leave everything you need to figure out approximately what you need in order to fulfill your personal goals.
Firstly, lets help define what a calorie is. We can define a calorie as the measure for the unit of energy in foods and beverages. A calorie is obtained by consuming macronutrients (scroll to the bottom for all definitions italicized). The three macronutrients include Protein, Carbohydrates, and Fats. Proteins are used by the body to develop, grow, and repair muscles and other bodily tissues after physical activity. Carbohydrates are used by the body as the main source of energy as they are converted to glucose in the body. Fats are used mostly during times of low-to moderate-intensity exercise as well as at rest. Fats are also important in providing structure to cell membranes, aiding in the production of hormones, forming the insulation that wraps nerve cells, and facilitating the absorption of fat-soluble vitamins.
How many calories do I need?
Total Energy Expenditure is the sum of your calorie needs over a 24-hour period. This is composed of:
BMR – Basal Metabolic Rate
TEF – Thermal Effect of feeding
Physical Activity – Your activity throughout the day including everything from getting out of bed to lifting weights.
We can approximate the BMR by using the Mifflin-St. Jeor Formula, this formula takes age, gender, weight, and height into account.
BMR = 10 x weight (kg) + 6.25 height (cm) – 5 x age (years) + 5 (men)
BMR = 10 x weight (kg) + 6.25 height (cm) – 5 x age (years) - 161 (women)
Physical Activity level is determined by choosing an activity level that matches you.
*NOTE THESE NUMBERS ARE ESTIMATES AND ARE DEPENDENT ON YOUR INTERPRETATION OF “LIGHT” “MODERATE”, “HARD” EXERCIESE
Step by Step Guide with Two examples:
I will take you through my own personal numbers so you can easily input your measurements and calculate everything for yourself.
Height = 6’ – 3” = 190.5 cm
Weight = 245 lbs. = 111.36 kg (let us use 111.5)
Age = 23 years
BMR Calculation:
BMR = (10) x (111.5 kg) + (6.25) x (190.5 cm) – (5) x (23) + 5 = 2196 calories
The BMR is the number of calories I require while remaining at rest with no activity. If I wanted to be a couch potato all day and not get out of bed I will burn off and need to consume my BMR to maintain my 245 lb. body weight.
Physical activity: (I will go through two scenarios here)
Scenario 1:
Current job = Engineer (desk job)
Lifting = Moderate activity 4 lifting days per week (approximately 2 hours per lifting day)
Activity Factor = 1.55
TEE (Total Energy Expenditure) = BMR * Activity factor => (2196) x (1.55) = 3403 calories
Scenario 2:
NCAA Student Athlete = walking approximately 2 miles per day
Lifting 3-4 days a week (Lifts approximately 45 min to 60 min)
Training 5-6 days a week (Practice approximately 1.5 hours to 2 hours)
Activity factor = 2.1
TEE (Total Energy Expenditure) = BMR * Activity factor => (2196) x (2.1) = 4612calories
As you can see the calories can begin to build up rather quickly when you live a more active lifestyle.
Calculating Required Protein, Carbohydrates, & Fats:
So now that we have our total calories what about macronutrients. Listed below you can find the list of macronutrients and their individual calories per gram conversion.
Calorie per gram of Macronutrient:
Protein = 4 calories per gram
Carbohydrates = 4 calories per gram
Fats = 9 calories per gram
Macronutrients can vary greatly depending on activity needs. Below we have created two tables to calculate your Macronutrient needs:
Macronutrients Calculation:
Scenario 1: (Engineer/Weightlifter)
Body fat ~ 15% (Rough estimates are okay to use)
Protein – Strength Athlete = 1g/lb. = (245 lb.) x (0.85) = 208 (let’s call it 210 g per day)
Carbohydrate – Moderate to low activity = 1.5 g/lb. = (245 lb.) x (1.3) = 318.5g (let’s call it 320 g per day)
To calculate fats, calculate the remaining calories that you need to fulfill:
Protein calories per day = (210 g) x (4 calories / gram) = 840 calories from protein
Carbohydrate calories per day = (320 g) x (4 calories / gram) = 1280 calories from carbohydrates
Total Calories – Protein calories – Carb Calories = Fat Calories => 3403 – 840 – 1280 = 1283 fat calories
Fat Calories per day = (1283 calories of fat) / (9 calories per gram) = 142.5 grams of fat per day
Scenario 2: (NCAA Student Athlete)
Body fat ~ 14% (Rough estimates are okay to use)
Protein – Strength Athlete = 1.2g/lb. = (245 lb.) x (1.2) x (0.86) = 252.8g (let’s call it 253g per day)
Carbohydrate – Ver Active = 2.5 g/lb. = (245 lb.) x (2.5) = 612.5g (let’s call it 610 g per day)
To calculate fats, calculate the remaining calories that you need to fulfill:
Protein calories per day = (253 g) x (4 calories / gram) = 1012 calories from protein
Carbohydrate calories per day = (610 g) x (4 calories / gram) = 2440 calories from carbohydrates
Total Calories – Protein calories – Carb Calories = Fat Calories => 4612 – 1012 – 2440 = 1160 fat calories
Fat Calories per day = (1160 calories of fat) / (9 calories per gram) = 129 grams of fat per day
Key Takeaways:
From comparison you may notice three changes.
1. Calories are much higher when your more active. The more you do the more you need to maintain. A bulk of the increased calories will be from carbs. There was a lot of mac and cheese I had to cut out of my diet when I graduated, and I do not want to go any further on this unfortunate circumstance.
Visual representation of me in college
2. Fats are slightly lower in total grams / day but much lower in % per day. Now I do not believe I was getting 600 g of carbs a day but as I am increasing the amount of intense activity the amount of fat needed lowers.
a. To adjust the numbers, I would increase the % of calories from fat to at least 30% to have a more rounded diet and reduce the % of calories from carbs.
b. Note that if I was a long-distance runner my calculations would change entirely. As long duration lower impact athletes use fats as a main source of fuel you will find that your fats may be much closer to the total calories needed per day.
3. Protein is increased. Even though I am currently a weightlifter and my total activity that is inducing muscular fatigue/breakdown of muscle was much higher. Pair that with the fact that my total calories is higher, and you will find protein will increase.
Please note that these numbers are good values to begin counting and may vary from individual to individual, as well as depends on the accuracy of your inputs. Before considering counting, calories attempt to make one or two better decisions a day pertaining to your diet and food/drink choices.
If you have any questions, feel free to reach out to us though our website. If you desire nutrition coaching/feedback contact us as well!
Definitions:
Macronutrient – These include carbohydrates, proteins, and fats and are classified as such because they have caloric value and the body has a large daily need for them.
Protein – Amino acids are the building blocks of proteins, which are constructed of carbon, hydrogen, oxygen, and nitrogen molecules. Amino acids can be made within the body or obtained from dietary sources.
Carbohydrate – compounds constructed of carbon, hydrogen, and oxygen molecules. Carbohydrates are converted into glucose in the body, providing the main source of fuel for all physical activity.
Fat – Composed up of carbon, hydrogen, and oxygen molecules. Fats are also known as lipids, and they come from both plant and animal sources in our diet. Fats are also important in providing structure to cell membranes, aiding in the production of hormones, forming the insulation that wraps nerve cells, and facilitating the absorption of fat-soluble vitamins.
BMR – Basal Metabolic Rate - the rate at which the body uses energy while at rest to keep vital functions going, such as breathing and keeping warm.
TEF- Thermal Effective Feeding – The food we eat requires energy to break down and digest. This accounts to approximately 10% of our total caloric expenditure.
All definitions taken from “Practical Applications in Sports Nutrition” Fifth Edition, by Fink & Mikesky
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