In The Lab, with Eric Martinez: How to Calculate How Many Calories to Consume

The information we are taught in school and through certification courses is extensive. We learn specific formulas in order for us to put them into best practice for our future clients. However, these formulas are not client centered and therefore, not exact. I’ve learned that those numbers are taught more as a guideline versus the “end all be all.” 

Let’s take the Resting Metabolic Rate Test (RMR) for example. There are three formulas that are thrown at us throughout the educational process:

Benedict Harries Formula

Lean Mass Time 11

Calculating Met Levels (for the day)

These formulas are great to get people started, but our metabolism is so erratic and unpredictable that we cannot solely rely on these numbers. Our habits, genes, and environment play a bigger influence than just our height and weight. 

Let’s review a recent case study: subject is a 30yr male, 67 inches tall, weighs 160lbs (130lbs of which is lean mass). Very active six days a week/for one hour a day.

Formula #1 The Benedict Harries Formula: 

88.362 + (13.397 x 72.72 kg of body weight) + (4.799 x 170.85 cm of height) – 5.677 x 30 age)

1,712 is the estimated RMR

Multiply that number by 1.55 (the activity factor) = 2,653.6

Formula #2 Lean mass equation:

130lbs (lean mass) x 11 = 1,430 

Multiply that number by 1.55 (the activity factor) = 2,216.5

Formula #3 Met Levels: 

The Met formula is similar to the Benedict formula, but the activity factor is broken down by force produced in time. 

Met * 3.5 * (72.72 kg in body weight)/200= Kcal per minute

Weight lifting = 6 mets (time moving the weight) = 458.136 kcal/hr

Sleep/ rest = 1 met = 610kcal per 8 hrs

Estimated TDEE (Total Daily Energy Expenditure) 

3,657 kcal on active days

Actual metabolism using a indirect calorimetry: 

1,465kcal on rest days 

2,342kcal on active days

These formulas illustrate that our subject has been under-eating by 1,315 calories (3,657-2,342) which is the reason for his low metabolism – along with his high caffeine intake consumption. 

We see a big range of numbers that don’t equate to the actual person; this is due to us bending equations, times, and totals. These formulas forget that the client may not be moving for the entire duration, providing misleading information. 

The mets and time doing weight is not correct. For example, nobody is moving weight for an entire hour, there are rest periods and breaks – and those are not being accounted for.

Habitual habits create a shift in our metabolism, such as eating too little or taking excessive stimulates (which decreases our metabolism over time). 

Living in a certain condition for long periods of time such as, higher altitude training, has shown to increase the metabolism due to its efficiency and need of Oxygen.

Additional factors relating to our gut and blood chemistry health can also make a shift into our metabolism direction.

Until next time, 
Eric Martinez, Co-Founder and Clinical Performance Specialist

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