Get ready for more acronyms than you can shake a stick at.
Everyone's fitness journey has a different beginning. Mine began because of sleep, or the lack thereof. I knew I needed better sleep, but I was unsure exactly how much sleep I was getting. So I purchased a cheap smartwatch and downloaded Samsung Health. I was amazed by what I was able to learn about my sleeping habits. But it was all the other metrics being collected, steps, heart rate, exercise, caloric intake, water consumption, etc., that got the ball rolling.
Seeing all those numbers made my health more tangible than ever before. I was hooked. Soon I began meticulously tracking my nutrition, leading me to learn about macros and micros. I started reducing processed foods containing words I couldn't pronounce and increasing my fruits and vegetables. I even went as far as going vegan for a while after watching The Game Changer because I wanted to see if my blood would visibly be different after giving up meat. It did (although the doctor's appointment was pretty strange because the only excuse I could come up with to get a random blood test was to get an STI screening).
But I thought, could becoming a "healthy person" be this easy? Short answer: No. It is a three-part equation consisting of sleep, diet, and exercise, and I was only beginning to succeed at one of them.
Enter my first gym membership in over a decade.
Like anyone else who goes to the gym, I wanted to see results from my investment. This led me to explore the nuances of eating like an athlete and the book by Nancy Clarke, Sports Nutrition Guidebook. Starting with Nancy Clarke is sort of like your first position out of school is CEO. It was a lot and I had to read that book about five times to really digest it. The first nugget of knowledge to jump out at me was TDEE.
Total Daily Energy Expenditure is the total number of calories your body burns daily. If you know how many calories you are burning in a day, you can easily get a handle on your weight by tracking your caloric intake.
Your TDEE can be broken down into two components: the number of calories your body requires for basic functions like breathing, thinking, growing, etc., and the number of calories your body burns when doing things like walking, running, and lifting heavy things at the gym.
The caloric requirement for essential functions is called your BMR (Basal Metabolic Rate). Determining your BMR is where the wheels fall off because to calculate your BMR, you need to know several things like how tall you are, your gender, age, and body composition, primarily LBM (Lean Body Mass). Except for LBM, everything on that list is pretty straightforward.
Your LBM is the amount of your body that is not fat. Bone, muscle, tendons, etc. But there is no way of measuring your LBM. Instead, you measure the amount of fat on a body, determine its weight, and then subtract that from the total body weight.
The Boer, James, and Hume formulas are considered industry standards when calculating a person's LBM, but all three formulas make assumptions regarding body composition. None of these formulas use actual body fat measurements. Let's face it; you cannot determine a person's LBM without directly measuring the amount of fat a person's body has.
Before going any further, it is important to clarify that several formulas are available to choose from when calculating BMR. Of the Mifflin-St Jeor, Harris-Benedict and Katch-McArdle, the latter is considered the most accurate and has become an industry standard because it is the only formula to consider LBM (although presumptive). The Katch-McArdle formal is likely buried within every TDEE calculator you find on the internet or app store.
Mifflin-St Jeor Equation:
For men:
BMR = 10W + 6.25H - 5A + 5
For women:
BMR = 10W + 6.25H - 5A - 161
Revised Harris-Benedict Equation:
For men:
BMR = 13.397W + 4.799H - 5.677A + 88.362
For women:
BMR = 9.247W + 3.098H - 4.330A + 447.593
Katch-McArdle Formula:
BMR = 370 + 21.6 (1 - F)W
or simply
BMR = 370 + (9.8 * LBM)
where: W is body weight in kg H is body height in cm A is age in years F is body fat in percentage
You can see how simply wondering what my diet should look like can quickly evolve into something I could use on my application to MIT. But I was determined to figure out my TDEE and what my macros should be and I had nothing but time on my hands during 2020.
The first calculator I built was very simple. It used three sets of parameters; weight, LBM and PAL. I left it up to the user to determine LBM but I was nice enough to include a link to a website that would give you figures based on the Boer, James and Hume formulas.
The difference in LBM numbers (106 - 113lb for a 5'6" male weighing 140lb) was enough to sway the results by 100 calories or more depending on the parameters for bulking, maintaining, or cutting weight. This might not seem like much but you have to consider the impact 100 extra calories per day can have over the course of a year. That's a ton of extra calories!
I briefly got derailed by the differences between BMR and RMR (Resting Metabolic Rate) because some formulas use RMR. But in the process of researching RMR, I came across this article on the NASM site. About halfway through the article, there is a section about Potential Errors that legitimized my concerns about the necessity of accurate data when attempting to calculate TDEE.
By my third version of the calculator, I had begun incorporating a check box that allowed users to choose between the formulas used for females or males.
The fifth version of my calculator used the Mifflin-St. Jeor formula and generated an RMR figure instead of BMR. This version also provided an alternative to using either the Boer, James or Hume formulas to calculate LBM.
Surprisingly, I continued down this path and kept making calculators! I'm not sure how many I made in the end but eventually, I concluded that no matter what formula I used, the results would be estimations unless I incorporated actual body composition figures.
I remember having my body fat measured as a kid using skin fold calipers. It seemed like a straightforward process and after doing a little research, I found that I could be the proud owner of my own set of skin fold calipers for the low, low price of $14.
Using skin fold calipers can be a little tricky. There are multiple formulas that use figures from different measurement sites to calculate body fat percentage. The most common method requires four points of measurement, two of which are on the posterior side and difficult to reach. This method uses the Durnin & Womersly equation.
The Jackson and Pollock formula only requires three points of measurement and is more accurate when determining body fat percentages in athletic individuals with low amounts of body fat (below 12% for males and 15% for females).
In 2020, I was not prepared to risk contracting Covid for the sake of having someone help measure my back fat. I also knew that my body fat percentage would be on the low side. So I combined the Jackson & Pollock formula for calculating LBM with the Katch McArdle formula for calculating BMR.
The results were surprisingly different from all previous versions of the calculator. My BMR was an astounding 110 - 120 calories higher when incorporating a more accurate LBM into the equation. Since protein and fat intake can be directly derived from body weight, it was my carbohydrates that were impacted by the discrepancy. Carbs equal energy so I want every carb I can get my hands on while staying within the guidelines of my goal.
If my goal was to maintain weight, the new calculator using the Jackson & Pollock skin fold formula with the Katch McArdle BMR formula resulted in my macros breakdown being as follows: Protein 140 grams (or 560 calories), fat 56 grams (504 calories), and carbs 234 grams (935 calories).
Of all the previous versions of the calculator that used a formula to estimate LBM, the closest I got was the following macros breakdown: protein 140 grams (or 560 calories), fat 56 grams (504 calories), and carbs 199 grams (796 calories).
That is a difference of 139 calories worth of carbs. That's more than a slice of bread! That's an apple, some carrots, and an entire head of iceberg lettuce!
Now some of you may have noticed the elephant in the room. Lurking in the corner, the giant sign around its neck reads, "PAL." Let me break it to you. PAL is not your friend because no matter how hard you try to figure pal out, it will always be a stranger.
PAL stands for Physical Activity Level and is a numerical range that represents a person's daily activity level. The more active you are, the higher the number. Within the fitness industry, it has become a standard in which you use a person's PAL multiplied by their BMR to determine their TDEE. In almost every bodybuilding cookbook, you will find a TDEE equation that refers to PAL. But look closely, and you may notice the numerical ranges are defined differently from one source to another.
In one of my favorite cookbooks, The Ultimate Bodybuilding Cookbook by Kendall Lou Schmidt, she breaks down PAL into the following options:
Little to no exercise = 1.2
Light exercise ( 1 to 3 days per week) = 1.375
Moderate exercise (3 - 5 days per week) = 1.55
Heavy exercise (6 - 7 days per week) = 1.725
Very heavy exercise (twice per day, extra heavy workouts) 1.9
Scott Herman has a meal planner web app on his site that breaks down PAL without any numbers:
Little or no exercise and desk job
Light exercise or sports 1 - 3 days a week
Moderate exercise or sports 3 - 5 days a week
Hard daily exercise or sports and physical job
But when you check the site's source code, you can find that the options of activity level correspond with 1.2, 1.35, 1.55 and 1.9 respectively. For anyone keeping score, the difference between a 1.55 and 1.9 for a 140 lb male is more than a Big Mac or three Sundays with syrup.
It's safe to say that PAL plays a huge role in determining someone's TDEE. There is so much research on RMR, LBM, BMR, REE, and TDEE. Where did PAL even come from? Well, here is a quick deep dive.
Start with the Wikipedia page for PAL and you'll find the oldest article cited is an article covering the topic of total energy expenditure and physical activity levels in adults and the data collected from double-labeled water. Within this article, there are too many amazing things to cover but the most interesting is how vastly different they define PAL numbers.
Here are a few highlights:
"A PAL of 1.35 has been suggested as the lowest PAL compatible with long-term weight maintenance in persons other than the completely chair- or bed-bound."
"The modal value of 1.55-1.65 for adults in the analysis falls between the light and moderate categories. The suggested range for strenuous occupation of 2.0-2.4 is compatible with the recommendation of 2.10 for heavy occupations."
"The FAO/WHO/UNU Expert Consultation (1985) suggested the average daily energy requirement of adults whose occupational work is classified as light, moderate, or heavy, expressed as a multiple of BMR, to be as follows:
| Light | Moderate | Heavy |
Men | 1.55 | 1.78 | 2.10 |
Women | 1.56 | 1.64 | 1.82 |
It is obviously difficult to relate these categories to the data in the analysis of DLW studies (Black et al, 1996), as the information on occupations was limited and the categories do not take active leisure into account."
This article also references the Schofield Equation which lists PAL as follows:
Sedentary people of both genders should multiply by 1.3. Sedentary is very physically inactive, inactive in both work and leisure.
Lightly active men should multiply by 1.6 and women by 1.5. Lightly active means the daily routine includes some walking, or intense exercise once or twice per week. Most students are in this category.
Moderately active men should multiply by 1.7 and women by 1.6. Moderately active means intense exercise lasting 20–45 minutes at least three times per week, or a job with a lot of walking, or a moderate intensity job.
Very Active men should multiply by 2.1 and women by 1.9. Very active means intense exercise lasting at least an hour per day, or a heavy physical job, such as a mail carrier or an athlete in training.
Extremely active men should multiply by 2.4 and women by 2.2. Extremely active means an athlete on an unstoppable training schedule or a very demanding job, such as working in the armed forces or shoveling coal.
Eventually, you end up at the Institute of Medicine Equation from September of 2002 in which an updated PAL breakdown appears but is referred to as PA instead of PAL.
Activity Level | Body aged 3-18 | Obese boy aged 3-18 | Girls aged 3-18 | Obese girls aged 3-18 | Adult Men | Adult Women |
Sedentary | 1 | 1 | 1 | 1 | 1 | 1 |
Moderately Active | 1.13 | 1.12 | 1.16 | 1.18 | 1.11 | 1.12 |
Active | 1.26 | 1.24 | 1.31 | 1.35 | 1.25 | 1.27 |
Very Active | 1.42 | 1.45 | 1.56 | 1.6 | 1.48 | 1.45 |
"Sedentary means only the light physical activity associated with independent living, moderately active means about half an hour of moderate to vigorous exercise in addition to this. Active means at least an hour of exercise and very active means being physically active for several hours each day."
We now have legitimate sources defining the highest level of activity for adults anywhere from 1.45 all the way up to 1.9 and in some rare cases individuals topped off around 2.4 when in the midst of "rigorous training" or Gambian women in the middle of farming season.
Here's my acronym for the list: WTF
How could something so widely adopted by the all-encompassing health industry be so obtuse?
Is this the secret sauce behind Whoop? Could we use biometric data collected from wearables to generate a number that does work? Maybe.
What I do know from years of logging my nutrition in MyFitness Pal, Samsung Health and Fitbit is that I have been able to reverse the equation and figure out my PAL by eating the same thing for weeks while training the same amount. What really surprised me is that I rarely go above 1.3 When I do go over 1.3 it's because I have run at least 3 of the league's training blocks to the T and my body starts becoming desperate for nutrition to avoid overtraining.
These PAL numbers seem pretty low compared to all of the other sources, but this is what has been working for me so far. I'd love to get a bigger sample size, so I included the most recent version of the TDEE calculator with every training program available from The Lift League. When you purchase a training block, the TDEE/Macro Calculator has it's own tab for you to check out and use. Personally, I use it at the beginning of every block as a way of checking progress. It's also pretty cool when you come back and repeat a block a year later and see where you were at.
Boer P. "Estimated lean body mass as an index for normalization of body fluid volumes in man." Am J Physiol 1984; 247: F632-5
James, W. "Research on obesity: a report of the DHSS/MRC group" HM Stationery Office 1976
Hume, R "Prediction of lean body mass from height and weight.". J Clin Pathol. 1966 Jul; 19(4):389-91.
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