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Calories Matter

Calories matter.  You know you can survive for a period of time without food, but not forever.  Taking food in, gives us calories, which provide the energy we need to survive, to function, and to thrive.  Don’t truly understand all of this?  Let me explain…


Basal Metabolic Rate (BMR)

Every human has their own personal basal metabolic rate.  This is the amount of calories you burn on a daily basis just to survive.  Basically, if you literally laid in bed all day and didn’t move, this is what you would burn for your internal organs to keep you alive.


Total Daily Energy Expenditure (TDEE)

Besides the basal metabolic rate, we also have something called our total daily energy expenditure.  This is the amount of calories you burn on a daily basis by living your life.  This number includes your basal metabolic rate plus your activities – and I mean all activities.  This includes the simple tasks (ie: just walking around the house or workplace to do your normal routine tasks), household and family tasks, work tasks, and exercise.


Why do these numbers matter?

When we think about total caloric intake required, we need to think about both numbers – what it takes to survive as well as what it takes to thrive.


Basic Survival

Ultimately, at a minimum, you need to be consuming enough calories to equal your BMR.  Technically, if you don’t even consume that amount, you cannot survive. Yes, you can survive for a period of time, as we have witnessed throughout history during a number of different events, but eventually your body will shut down.



In order to have good energy, our caloric intake needs to be adequate.  This means in the range of our TDEE.  We will lose weight effectively at a deficit of 100-300 calories/day, but if the deficit is much larger than that, our bodies will conserve energy.

You won’t realize it, but if you go below the TDEE too drastically for too long, your body will naturally move less – you will fidget less, you will shift around in your chair or when standing less often, you will avoid walking places (ie: fewer trips to the copy machine at the office or finding the closer parking spot).

Feeling tired and sluggish during the day?  Too big of a caloric deficit may be contributing.  There are a lot of factors that could be contributing, but low caloric intake is one of them.

Plateaued in your weight loss?  Too big of caloric deficit for too long will cause this.  Your body will lose weight temporarily, but eventually it will turn to conservation and hold onto what it can.



When you are training or competing, you may feel that you have good energy.  But you may be shocked how much more energy you have if you increase your caloric intake a bit – even just by 100-200 calorie – especially if you are in a significant deficit.  I have worked with dozens of athletes who have increased their caloric intake and report having a significant increase in energy when training.

Along with feeling like you have more energy, you will also notice better endurance and strength gains.  You can’t make significant gains in speed, endurance, or strength if you don’t have the necessary energy requirements to support it.  This means you likely won’t begin to hit personal bests or PRs if you don’t have the energy to support it.



Because our bodies need a certain amount of calories to survive, if we don’t intake enough, it will pull from somewhere.  Along with the decreased performance with decreased consumption, it can also lead to increased risk of injuries.

The reason is twofold.  First, if you don’t have the energy and fatigue faster, your body may begin to compensate in order to perform the necessary requirements of the activities.  Over time, compensations cause injuries.  Secondly, you need calories to maintain or build up your tissues (muscles, tendons, ligaments, bones).  If you don’t have those calories needed, you either don’t build the tissues properly or your body starts to pull from them.


So what now?

Are you just realizing how important your nutrition is to your survival, your energy, your performance, and your health?  Awesome!  I am glad this helped you understand that better.


Concerned you may not be eating enough?  The first step to begin to figure this out is by tracking your food intake on a food log.  I personally suggest MyFitnessPal, but there are others out there that you can use.  Once you begin to see how much you are eating, you can begin to determine if it is enough for you.


Comment below with your thoughts!  Email me at with your questions.

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