Feeding the Fitness Machine: RMR and Nutrition

It’s November, and with the holidays right around the corner, this post from Staff Coach Joe could not be any more timely. With Thanksgiving and Christmas fast approaching, good fitness and nutrition habits tend to fall by the wayside.

So how can we truly enjoy the holidays, without paying the price when it comes to physical health?

As it just so happens, the third pillar of our regeneration suite is nutrition, so now is a great time to talk about this dilemma. We had also yet to discuss the last component of our metabolic lab, resting metabolic rate (RMR). Well, that’s about to change. Today, find out why RMR is important when it comes to nutrition, and how you can stay ahead of the curve during this season of gluttony.


When it comes to nutrition, metabolism is often talked about as something that can be easily manipulated to facilitate muscle gain or fat loss. It’s not uncommon to hear things like “boost your metabolism 10x using these 4 exercises!” or “eat these superfoods to boost your metabolism” or even better: “here’s the supplement of the year for melting fat away!”

Agitated young woman looking up in frustrationWell now…if only if were that easy. Let us start by saying that you might want to put your green tea down (unless of course you enjoy drinking it, that’s perfectly fine), toss your raspberry ketones into the nearest waste disposal, and temper the expectation that you’re going to add 10 pounds of “lean muscle” (because fat muscle is a thing?) or lose 10 pounds of “pure fat” in 28 days. All while significantly increasing your metabolism to that of an energy burning machine. It just doesn’t happen that fast.

Now that we’ve quickly established what doesn’t work, let’s shift our focus to what the research has proven to be an effective method of weight loss. By far, the most important factor to sustainable weight loss is establishing a healthy lifestyle based on your specific needs. It’s much easier to succeed by design than by willpower. Design, you change once to create a habit; willpower, you must re-establish at each and every instance of challenge.

The most fundamental component to any weight loss plan is the balance of energy (Calories in vs. Calories out). Eat more than you burn, and you’ll gain weight, hopefully muscle. Eat less than you burn, and you’ll lose weight, hopefully fat. Still, it is important to understand what variables make up the energy balance equation.

Calories in (also known as energy intake) is the energy consumed by the body through food. All foods contain a certain amount of energy based on its composition of nutrients.

Calories out (also known as total energy expenditure) is made up of four different components: basal or resting metabolic rate, the thermic effect of activity, the thermic effect of food, and non-exercise activity thermogenesis.

Remember the term basal/resting metabolic rate (RMR). It’s important to us here today, because RMR is basically your metabolic fingerprint. It refers to the energy needed to support the most basic of bodily functions such as respiration and circulation. It’s the minimum amount of calories you need to burn to stay alive.

RMR accounts for 60-80% of total daily caloric expenditure. It can vary up to an estimated 20% within individuals of similar physical characteristics, due in large part to the contribution of genetics. This is incredibly important, and a large part of why we quite often hear “I can’t lose weight in a caloric deficit” or the even more outrageous “I’m gaining weight, but I’m not eating anything bad”.

It has been well established through various research publications that:

  1. Individuals are unaware of exactly how much they are eating and grossly underestimate their daily caloric intake.
  2. RMR prediction equations show a variance of up to 15% when compared to indirect calorimetry.
  3. Individuals often over estimate the intensity of their workouts, and the resulting caloric expenditure.

Let’s have a look at how just one of these variables can impact the energy balance equation, and therefore impact expected weight loss.

Utilizing the well-respected Harris-Benedict equation for a 24-year-old male at 5’10″ and 170 pounds, an RMR of 1882 kcal/day is predicted. With a 15% variance, a true RMR as measured by indirect calorimetry may be anywhere from 1,599 or 2,164. That’s a difference of nearly 300 kcal/day both ways!

If an equation-predicted RMR can vary by 15%, and if RMR makes up anywhere from 60 to 80% of total daily caloric expenditure, that leads to a huge margin of error when it comes to calorie-counting.

For argument’s sake, let’s say that you have an RMR at 1882 kcal/day. RMR is anywhere from 60-80% of total daily caloric expenditure; let’s say that it’s 70%. Then, your total daily caloric expenditure would be 2689 kcal/day.

Let’s now say that you were recommended a 2,189 kcal/day diet based on total daily energy expenditure in expectation of creating a caloric deficit of ~500 kcal/day and 1 pound of weight loss per week.

But what if your total daily caloric expenditure is actually 2189? This is entirely possible; an RMR of 1751 that is 80% total daily caloric expenditure would result in that. 1751 is well within the range of 1599 to 2164 for a 24 year-old male at 5’10” and 170 pounds.

If your energy intake and energy expenditure are both 2189, is it wrong to say it would be false hope to expect weight loss as a result of what is now a maintenance diet in terms of energy balance? As you can see, this is just one component of the energy balance equation that often disrupts any weight loss approach.

Thankfully, this is easily correctable. A measurement of your specific resting metabolic rate through clinical-grade indirect calorimetry provides a precise caloric breakdown of your metabolism to eliminate the variation inherent to prediction equations.

Completing an RMR test gets you one step closer to designing a program to succeed in the often overwhelming weight-loss pursuit.

Now, back to the groups of “I can’t lose weight in a caloric deficit” or the even more outrageous “I’m gaining weight but I’m not eating anything bad” mentioned above. There is no debate that there are individual differences in metabolism between people. That may explain why it seems like your friends can eat whatever they want and work out less intensely than you do, but experience better results. However, the laws of thermodynamics apply to everyone. It is physiologically impossible to store more calories than you’ve consumed.

calories-mismatch-dos-equis-memeAfter consuming 500 calories, the absolute MOST you would store is 500 calories (without even considering the thermic effect of feeding), and I’ll eliminate that variable to further prove my point. Energy cannot simply be created from nothing. Therefore, you cannot store more energy than you’ve consumed. A 250-lb individual whose maintenance caloric intake is self-calculated at 3500, who claims that they gained weight on a 1500-calorie diet raises extreme skepticism.

I would graciously conclude that either their energy expenditure or energy consumption was grossly miscalculated, and thus their energy balance equation has put them at a disadvantage in their design. More than likely, it is a combination of both.

So when people say the energy balance equation is invalid and refer you to supplements and fad diets with complete incompetence, be mindful of the exaggerated expectations. The equation is completely valid, what is invalid are the assumptions that are made about what the equation entails.


Knowing your RMR with clinical-grade precision can take you one step closer to your fitness goals, whether they be to lose weight or gain muscle. Be sure to find out more about our metabolic lab and sign up to find out what your unique metabolic fingerprint is here: Metabolic Testing at Halevy Life.

Once we know your RMR, we can then provide tailored nutrition advice based on that information to help you stay ahead of the curve this holiday season. Find out more about the third pillar of our regeneration suite here: Nutrition Counseling.

Happy training, and happy eating, too!

Sources:

Brooks, G.A., T.D. Fahey, T.P. White and K.M. Baldwin. Exercise Physiology: Human Bioenergetics and Its Applications. Mayfield: Mountain View, Calif., 2000.

Schoeller DA. The energy balance equation: looking back and looking forward are two very different views. Nutr Rev. 2009 May;67(5):249-54.

Speakman, J.R. and Selman, C. (2003) ‘Physical activity and resting metabolic rate’, Proceedings of the Nutrition Society, 62(3), pp. 621–634.

by Joe Ferraro