Before you can use any sort of bodily formulas and calculations, you need to collect, at a minimum, the following data points: Age, Height, Weight, Neck measurement, Waist measurement, and wrist measurement. From these 6 data points, you can calculate all kinds of cool stuff.
Lets start off with these data points (not mine, just examples):
| Age (A) |
35 yo |
| Height (H) |
70 inches |
Weight  |
190 pounds |
| Neck (N) |
15 inches |
| Waist (Wa) |
35 inches |
One of the fist things we can calculate is Body Mass Index (BMI)
Body Mass Index (BMI)
BMI = (703 x W) / (H x H)
BMI = 27.3
Now, the BMI scale is not accurate for athletes. According to this number, 27.3, is considered “overweight.” But is it? Let’s calculate the Body Fat % (BFP)
Body fat percentage (BFP)
There are different formulas, some maybe more accurate than others. One method, less accurate, is calculating based on the BMI number.
Body fat percentage (BFP) formula for adult males:
BFP = 1.20 × BMI + 0.23 × A – 16.2
Body fat percentage (BFP) formula for adult females:
BFP = 1.20 × BMI + 0.23 × A – 5.4
BFP (via BMI) = 24.6%
The U.S. Navy devised their own method of calculating which is used by most military branches. They have a very complicated chart and formula. You can download the Army App and plug in the data.
BFP (via Navy) = 17.4%
Notice the huge difference. When using the Bod Pods and electrical scales that measure tissue density, we find that the Navy formula is more close than going off the BMI. So, we will stick with the Navy number of 17.4%
Fat Mass
So how much of Body Fat Mass do we have?
Fat mass (FM) formula:
FM = BF × Weight
FM = 33.1 pounds of fat.
Lean Mass
But we also want to know how much Lean Mass (LM) we have as well.
Lean Mass (LM) formula:
LM = Weight – FM
LM = 156.9 Pounds of Lean Mass.
Lean Mass is a very important number. You always want high lean mass. When you workout, you don’t want to lose lean mass.
Ideal Weight Calculator (IBW)
Ideal Weight Calculator (IBW) estimates what your optimal weight would be given all known scientific data about how the human body works. There are several formulas that have been proffered over the decades of sports science, but we will go with Robinson, 1983. This number seems to consider the weight of lean mass and muscle.
J. D. Robinson Formula (1983)
| Male: |
IBW = 114.6 LBS + 4.2 LBS per inch over 60 inches |
| Female: |
IBW = 108 LBS + 3.7 LBS per inch over 60 inches |
IBW = (((H)-60) x 4.2) + 114.6
IBW = 156.6 LBS
Body Surface Area
Body Surface Area is a fun one. It’s more like, how big are you, or how much space do you take up.
Haycock Formula:
BSA = 0.024265 × W0.5378 × H0.3964
BSA = 22.37 ft.
That means, the total body size takes up 22.73 square feet.
DIETING DATA:
For dieting, there are several numbers we want to know what kind of diet plan works best. First it is important to know how many calories your body NEEDS to consume each day. It is a simple guideline for calorie intake.
The Basal Metabolic Rate, Calories Needed (BMR1)
Revised Harris-Benedict Equation:
For men:
BMR1 = 13.397(W) + 4.799(H) – 5.677(A) + 88.362
For women:
BMR1 = 9.247(W) + 3.098(H) – 4.330(A) + 447.593
BMR1 = 2771.03
BMR1 shows how many calories we NEED to consume, BMR2 estimates how many we ARE consuming.
The Basal Metabolic Rate, Calories Burning (BMR2)
The Basal Metabolic Rate (BMR) is a useful number. This number gives you an estimated Metabolic Rate or how many calories you’re burning not being active and 12 hours of rest. I prefer the Katch-MacArdle Formula because it includes BFP.
Katch-McArdle Formula:
BMR2 = 370 + 21.6 (1 – BFP) W
BMR2 = 1,915 Calories, daily, inactive.
Any less calories than that, you’re body will start to burn off fat, and then burn muscle.
Now, if you were working out 6 days a week (like me), that number than changes. That would be an estimated 52% increase in daily activities, thus boosting my BMR to 3,639 calories daily.
Calorie Deficit (CD)
So, we can get a gross estimate of our calorie deficit by subtracting BMR2 (working out 6 days a week) from BMR1.
CD = BMR2 – BMR1
Calorie Deficit (CD) = -867
That is a rather large deficit. Studies show that a long term deficit over 500 will cause your body to go into a sort of starvation mode where it starts burning muscle and automatically storing everything as fat. So, the CD number tells us that we need more calories in our diet, roughly 400 to 500 more, or an extra meal.
MACRO GOALS
Determining your Macros, or how many Protein, Carb, and Fat someone should take is CRITICAL to weight loss and even muscle gain.
Carb calculation is a good starting point. The Institute of Medicine recommends American and Canadian adults to get 40% to 65% of their dietary energy from carbohydrates. The Food and Agriculture Organization and the World Health Organization jointly recommend 55% to 75% of total energy from carbohydrates, but only 10% directly from sugars.
Clearly if we want to lose weight and burn fat, we want the lower end of the recommendation.
Carbs = 40% AND less than 10% of sugar.
To be honest, I dropped mine to 30% and 5% sugar.
So if we go back to our BMI1 (2,771), 30% of that is = 831 Calories of Carbs. 1 gram of Carbs is equal to 4 calories; therefore, we only want 207 grams of carbs, daily. Since sugar is only 5%, that means we only want 138 calories and no more than 34 grams of sugar, daily.
1g Carb = 4 Calories
30% Carb = 207g of Carbs with a BMI1 of 2,771.
5% Sugar = 34g of Sugar with a BMI1 of 2,771.
Total Calories = 828
Next we need to find our Protein Intake number.
The American Dietetic Association (ADA) recommends when considering age, height, weight, and activeness ( workout 6 days a week), at least 86-155 grams of protein a day.
The Centers for Disease Control and Prevention (CDC) recommends 76-266 grams daily.
If we are building muscle, we want the most amount of protein possible, so we will go with the CDC’s highest recommendation of 266 grams.
We should reverse calculate to determine what percentage of our total calorie intake this is. Protein is about 4 calories, much like carbs. Therefore, 266 grams is equal to 1,064 calories; which is about 38-40% of our daily calorie intake.
1g Protein = 4 Calories.
38% Protein = 266g of Protein with a BMI1 of 2,771.
1.4 x W = Protein Grams Per Pound of Body Weight
Total Calories = 1,064
Finally, we have our fats. FATS are NOT your enemy. They are used for fuel and training your body to break down body fat.
The Mayo Clinic recommends the a daily fat allowance of 20-35% of your daily calorie intake. Considering that we wiped sugar and carbs out of your diet, we need to fill that void with healthy fats. All we have to do is subtract our Carb Intake % and our Protein Intake % to determine our Fat Intake %.
30% (carbs) – 38% (Protein) = 32% (fat)
1g Fat = 9 Calories.
32% Fat = 98.5g of Calories of Fat with a BMI1 of 2,771.
Total Calories = 886.5
AND BOOM, you have your Macro Goals!
- 30% Carbs (5% sugar)
- 38% Protein
- 32% Fat
- BMR1 = 2,771 calories
- CD = -867 calories
- Working out 6 days a week.
| BMI |
BMI = (703 x W) / (H x H) |
27.3 |
| BFP (Navy) |
|
17.4 |
| FM |
FM = BF × Weight |
33.1 |
| LM |
LM = Weight – FM |
156.9 |
| IBW |
IBW = (((H)-60) x 4.2) + 114.6 |
156.6 |
| BSA |
BSA = 0.024265 × W0.5378 × H0.3964 |
22.37 |
| BMR1 |
BMR1 = 13.397(W) + 4.799(H) – 5.677(A) + 88.362 |
2771 |
| BMR2 |
BMR2 = 370 + 21.6 (1 – BFP) W |
1915 |
| CD |
CD = BMR2 – BMR1 |
-867 |
There are a ton more numbers to learn. Another super important number is your One Max Rep (1MR) number. But that requires you going to the gym and lifting something heavy. But it is based off that number, that all your reps and sets come from.
One Max Rep (1MR)
So, if you go to the gym and curl a 45 Pound dumbbell, 4 times, your 1MR for Dumbbell Curl would be: 50 LBS
In theory, you should be able to curl a 50 pound dumbbell one time. And that would be your MAX weight.
1MR = Weight Lifted x (1+(0.033 x Reps))
1MR for Dumbbell Curls = 50 LBS.
Strength To Weight Ratio
Then, if your goal is to build muscle, all your weight with that workout would be anywhere between 70-80% of your 1MR for that workout.
Then you can calculate your Strength To Weight Ratio
StWR = 1MR/ Body Weight
StWR for Dumbbell Curls = 0.26
This number means more when you are dead-lifting and bench pressing.
Hope you educate yourself and enjoy. Ill add more formulas as time goes one.
The Life Gym 
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