Calculating Macros for Weight Loss and Muscle Gain
As an athlete, macronutrient (or macros) intake is a key component not only for recovery but for being able to get the most out of your workout. There are several factors to take into account when calculating your macros but first let’s learn what macros are and why they are important.
The Macros
Fat, carbohydrates, and protein are what we refer to as macronutrients. Macronutrients are nutrients that we need in larger quantities to sustain metabolic functions.
Carbohydrates provide the primary energy for daily activities and support brain function.
There are 4 calories per 1 gram of carbohydrate.
Fats are a concentrated source of energy, help with hormone regulation, and in absorbing fat-soluble vitamins.
There are 9 calories per 1 gram of fat.
Proteins are essential for building and repairing tissues, muscles, hair, and nails.
There are 4 calories per 1 gram of protein.
Calculating individual macro needs requires additional information including activity levels, training objectives and most importantly your goals! Most equations utilize kilograms and centimeters, the following shows how to convert pounds and inches:
Weight in lb / 2.2kg/lb = kg
Height in inches x 2.54cm/inch = centimeters
There are many equations that can be utilized to calculate your resting metabolic rate (RMR), that is the calories needed at rest, here are a few equations:
Mifflin - St Jeor
Men: RMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age (yr) + 5
Women: RMR = 10 x 10 x weight(kg) + 6.25 x height(cm) - 5 x age (yr) - 161
Harris-Benedict
Men: BMR= 66.473 + (13.7516 x weight (kg)) + (5.0033 x Ht (cm)) - (6.755 x age (yrs)
Women: BMR = 655.0955 + (9.5634 x weight (kg)) + (1.8496 x Ht (cm)) - (4.6756 x age (yrs))
Cunningham
RMR = 500 + 22 x FFM (kg)
FFM = fat free mass
Katch-McArdle
RMR = 370 + 21.6 x LBM (kg)
LBM = Lean body mass
Once we have calculated our RMR we can convert to total daily energy expenditure (TDEE), this is the energy we use with movement, the following are activity factors:
Multiply RMR by an activity multiplier:
Sedentary/desk: x 1.2
Light exercise (1-3 days/wk): x1.375
Moderate (3-5 days/wk): x 1.55
Very active (6-7days/wk, heavy training): x 1.725
Extremely active (2x/day training): x 1.9
These factors are approximations, for athletes, activity energy expenditure can vary day to day. Many nutrition tracking apps calculate this additional calorie need for you and adjust total daily calories automatically. The important take away is when you are trying to build muscle and whether you are trying to gain or lose weight as well, it is vital to consume enough energy to replace what was lost to ensure the body has adequate energy for muscle growth and basal metabolic functions.
Converting Calories to Grams
When starting out with macro counting a reasonable initial macro split is 45% carbohydrates, 30% fat, and 25% protein. Here’s why:
Carbohydrates 45-65%
The Institute of Medicine’s (IOM) AMDR (Acceptable Macronutrient Distribution Ranges) recommends carbohydrates at 45-65% of total energy intake for adults. Carbs are the body's primary source of energy, they fuel high intensity training and replenish glycogen stores aiding in recovery. 45% is the lower end of AMDR which allows room for increasing protein or fat as needed.
Fat 30%
A 20-35% range is recommended by IOM/AMDR to ensure essential fatty acid intake and fat-soluble vitamins. 30% is comfortably within that range and leaves room for carbohydrates to support high training loads while supplying adequate dietary fat for hormone production and recovery.
Protein 25%
The general AMDR for protein is 10-35%, but for exercising individuals the ISSN and other positions recommend absolute intakes (not just percent): ~1.4-2.0 g/kg/day (depending on endurance vs strength training and goals) to support muscle protein synthesis and recovery. A 25% energy allotment for protein tends to map protein intakes in that recommended grams/kg range for many athletes.
Percent-based splits give a quick, practical template to plan meals and ensure macro balance while you convert into grams (and check protein g/kg). For athletes, it’s critical to verify absolute protein (g/kg). If the percent split produces <1.4 g/kg protein, raise protein even if that lowers carbs slightly. These are starting goals and can be adjusted as needed as time progresses with training. Remember different end goals will have different macro adjustments.
Powerlifting, Bodybuilding, Crossfit:
Protein intake ~2.0g/kg recommended
~45% carbohydrates
~30% fat
Endurance athletes (cyclists, runners, cross-country skiers, swimmers):
Protein intake ~1.4-1.6g/kg
~50% carbohydrates
~30% fat
Regarding individual sports protein needs vary based whether in-season, pre-season, or out-of-season. These recommendations are also variable sport to sport.
Now that we have our total daily calories calculated out we can figure out our macros. Before we do this though let’s talk about weight loss and weight gain goals.
Fat Loss:
A moderate deficit is recommended of 500 calories/day. A safe weight loss goal that is sustainable long-term is 0.5-1.5lb/week. In order to lose 1lb per week we need to be in a 3,500 calorie deficit.
Equation: TDEE - 500 calories = Final total daily Calories
Muscle Gain:
A moderate surplus of +250-500 calories/day is recommended to aid in gradual safe muscle/weight gain.
Equation: TDEE + 500 calories = Final total daily calories
The amount of each macronutrient in grams to include in your diet is based off the total daily calories. Let’s work through this in an example:
Bill is a beginner powerlifter working out 4-5 days per week for at least 2 hours. His current weight is 215lb, height 6’0”, and 40 years old. His goal is to lose fat but gain muscle.
First, let’s convert height and weight into metrics.
215lb / 2.2kg/lb = 97.522 kg
72” x 2.54cm/inch = 182.88 cm
Second, let’s determine our TDEE using the Mifflin-St Jeor Equation for RMR and 1.55 for our activity factor .
Men: RMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age (yr) + 5
10 x 97.522kg + 6.25 x 182.88cm - 5 x 40 + 5 = 1923 RMR calories
1923 RMR calories x 1.55 activity factor = 2980kcal
Remember, if using an app to track macros your activity if synced will adjust TDEE . You can try to keep track of this hard copy if you would like however, I would recommend against this as it will be an absolute pain in the ass.
Third, determine final total calories with a goal of fat loss.
2980 RMR calories - 500 calories = 2480 final total daily calories
When creating a calorie deficit if 500 calories feels too aggressive drop it gradually and hold for 2-4weeks before dropping again. Do not exceed a 500kcal deficit. Too great a deficit will slow your metabolism and plateau weight loss and muscle gains.
Fourth, determining macros based on goal of fat loss and muscle gain.
Protein
2.0g/kg recommended
97.52kg x 2.0 = 195g protein per day
195 g protein x 4kcal/gram = 780kcal
2480 final total daily calories - 780kcal = 1700 calories remaining for carbs/fat
Carbs 45-65%
2480calories x 0.45 = 1116 calories
1116 calories / 4calories/gram = 279g carbohydrates
279g carbs x 4calories/gram = 1116 calories
1116 calories + 780 calories = 1896 calories
2480calories - 1896calories = 584 calories remaining
Fat 20-35%
584kcal / 2480 calories = 24%% of calories from fat
584 calories / 9grams/calorie = 65 grams fat daily
Initial Macro Goals:
Protein: 192grams
Carbohydrates: 279 grams
Fat: 65grams
Total Daily Calories: 2480
If you are not working out consistently or the intensity of your workouts have changed then your macro needs have changed as well. Remember these are starting points and everyone's macros needs are individual based on activity, age, and genetics.
I recommend when starting to track macros obtaining a food scale and downloading an app like MyFitnessPal, Macros First, LoseIt!, etc., to aid in tracking. Foods do not all fit nicely into one macronutrient category but rather have a mix of macros which can be confusing when starting. For example, chicken has fat, water, minerals, and protein contributing to its weight which means the weight is not solely reflective of protein. This is where apps can make understanding the composition of foods easier.
If this all seems like too much to sort out and adjust on your own let’s work together to achieve your athletic goals:
Mifflin, M. D., St Jeor, S. T., Hill, L. A., Scott, B. J., Daugherty, S. A., & Koh, Y. O. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 51(2), 241–247.
Harris, J. A., & Benedict, F. G. (1918). A biometric study of human basal metabolism. Proceedings of the National Academy of Sciences, 4(12), 370–373.
Cunningham, J. J. (1980). A reanalysis of the factors influencing basal metabolic rate in normal adults. American Journal of Clinical Nutrition, 33(11), 2372–2374.
Institute of Medicine. (2005). Dietary Reference Intakes: Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press.
International Society of Sports Nutrition. (2017). Nutrition and athletic performance. Journal of the International Society of Sports Nutrition, 14(1), 1–59.
International Society of Sports Nutrition. (2007). Protein and exercise: An ISSN position stand.Journal of the International Society of Sports Nutrition, 4(2), 1–12.
