1+1=? Why Calorie Counting is Impossible and What to do About it

We all know the mantra
  • Eat more calories than your burn = you gain weight
  • Eat less calories than you burn = you lose weight

This is a perfectly correct statement.  It is a basic law of thermodynamics. The problem is it is nearly impossible to know how many calories you are taking in or burning off on any given day.  

I’m not saying it’s impossible to get exact… 

…I am saying it’s impossible to get inside the ball park.

Why? For three main reasons:
  1. Calories In calculations can incorrect as a result of four factors
  2. Calories Out calculations can be incorrect as a result of four factors
  3. Calories are not created equal

…Lets start with Calories IN….


1. Food Packaging Information

Calorie counts on food in general (even whole, clean food) is based on an average which is likely not correct when reflecting what you actually ate.  For example, 1 large sweet potato can have as few as 231 calories or as many as 705. The average, which most calorie counting apps will use, will say somewhere in the mid 300s.  That can be a triple digit difference in only one food item of one meal of one day of your diet.

Also, food companies are allowed to use a number of different calorie estimate methods, and as a result the FDA allows inaccuracies of up to 20%

In a study done in Boston, scientists measured the actual calories in health conscious frozen meals.  They found that they often had 8% more calories than they stated on the package.  Which doesn’t sound like a lot, but if you ate 2000cal a day of the “healthy” meals, you would actually consume an extra 1120cal each week (almost an 8th day of calories).  A further downside (as you will see in this article) is that an 8% variable is about the best percentage you can expect.  So assuming you do not eat 100% of your calories from frozen health conscious meals, you can expect that 8% to be much higher.

Additional inaccuracies can occur year-to-year because calorie counts are not done frequently.  Therefore, changes in the natural factors of food growing or raising (feed, weather, soil content, etc.) can alter calorie counts.

The potential for discrepancy in food packaging accuracy is as high as 50%.

2. Variability in Absorption

Just because we eat the calories does not mean we absorb the calories.

We absorb different amounts of calories based on the food itself and how we cook it.  For example, we absorb only 68% of calories from almonds but 98% from pistachios.  Even apps that control for absorption rate, they only do so based on an average.  This can still lead to significantly incorrect numbers over the medium or long term. 

Different methods of preparation and cooking change how many calories we absorb in food as well.  For example, chopping or blending flood increases how many calories you absorb. Same as boiling, grilling or baking. Keeping it raw or searing reduces the number.

The potential for discrepancy in food specific absorption accuracy is as high as 10% and in cooking method is as high as 90%.

3. You are Unique

Your genes, gut biome, age, activity level, environment all affect how your food is absorbed.  This can cause differences in calories in.  Something as simple as a higher population of certain bacteria in your gut can cause a absorption of 150 cals per day than if you don’t have a that higher population. 

The potential for discrepancy is too variable to estimate.

4. We Are Bad Guessers

Portion Size Estimate.  If you are basing calories by the portion size, unless you are weighing every ounce of food, most people estimate sizes wrong – typically by making each portion a bit larger than actual. 

The potential for discrepancy is too variable to estimate.

As a whole, it is estimated that your calories in calculations, whether by app or some other method is off by an average of 25%.


1. Estimates are Imprecise

There are a few different ways to measure calorie burn.  Two of them are Direct Calorimetry and Indirect Calorimetry. 

Direct Calorimetry is where scientist put people in an isolation chamber and measure the heat their body gives off while resting, exercising, etc.  With a margin of error of 3.3% it is one of the closest to accurate methods out there … but it is also the most expensive.  Most estimators (on treadmills, watches, apps, etc.) do not use this because of the price.  They use Indirect Calorimetry.

Indirect Calorimetry measures energy expenditure through gas exchange (you have seen those videos of people running on a treadmill with a mask on their face).  This is a much more affordable option but can be off by as much as 45% because of dietary assumptions that have to be made for the burn calculation.  And we all know what they say about “ass +u+me’ing.” 

45% is a bit aggressive and your estimators are likely not off by that much.  However, on average you can expect most of your cal tracker watches to off by 10% or more.

2. You are Unique

Your caloric burn is affected by your unique genes, the external stressors in your life, your sleep amount and quality (or lack there of), and in the case of women, hormonal make up during various phases of their menstrual cycle.  I am sure your mom told you as she told me, “you are a unique snowflake,” and you burn calories accordingly.

The potential discrepancy caused by your uniqueness is as high as 20%

3. Calories Burned when Eating & Your Body’s Metabolism Adaptation Rate

Different people will burn calories while eating at different rates.  This is the chewing food, digesting food, transporting nutrients, and expelling waste. Depending on your unique make up, your consistent dietary intake, the specific foods you eat per meal, and a number of other factors, your body burns calories to digest at different rates than the next person.

On top of that some people’s metabolism will adapt to being overfed or underfed more effectively and efficiently than others.  Adaptation is basically saying that if you are consistently overfeeding yourself, your body will suppress hunger signals and increase its calorie burn to bring you back in to balance.  If you are underfeeding, the opposite happens. 

However, this does not happen at the drop of a pin.  It can take a little while for your body to adapt.  However, some bodies adapt quicker than others.  This means a slower adaptation to overfeeding means less calories burned than someone with faster adaptation.

This range can be quick drastic.  In an 8 week study, participants were overfeed by 1000 calories a day every day for the 8 weeks and asked not to exercise.  At the end, the individual who’s body adapted the quickest to the overfeeding only gained 0.79 pounds. But the individual whose body adapted the slowest gained 9.3 pounds!

The potential discrepancy caused by your specific digestive burn rate and body’s adaptation is as high as 20%

4. History with Weight

Your personal history with weight in general will affect you caloric burn.  

For example, lets say you were overweight and successfully reduced your caloric intake and lost weight. Congratulations to you! However, your body does not know about your weight loss goal, it just sees that it is getting less calories than before.  It freaks out and responds to the caloric deficit as if it were “starving.” This means your metabolism will slow down and preserve those precious few calories (remember the adaptation above…). 

Your body like balance and will adjust to re-find that balance when a change occurs, even if the change is a healthy one.  As a result, on average, someone who was large and then lost weight (aka changed) will require 300 less calories per day to maintain than someone who was always that same weight.  That is because the bigger person’s body adapted and the always thinner person’s body did not have to. 

The potential discrepancy caused by your history is as high as 10%

As a whole, it is estimated that your calories in calculations, whether by app or some other method is off by an average of 25%.


Not all Calories are Created Equal.  The quality of the calorie matters more than the quantity when it comes to body nutrition.

The best example of the quality vs quantity divide is The Low Calorie Facade

Let say you are counting calories and trying to keep your daily total low.  You want a snack so you decide to eat a 100cal pack of Oreos.  Eating that Oreo 100cal pack may keep your total calorie count low but your body will still add weight because:

1. You get less nutrients than 100 cal of a whole food,

It is common sense that you body needs macro and micro nutrients to function, thrive, fight disease, have energy, focus and think, etc.  Eating processed food, no matter the calorie count, will deprive your body of these necessary nutrients. 

2. You will be less full in general so you are eventually going to eat more.

You may fight the hunger tooth and nail but most people end up giving in in the end because it is really hard to ignore your body’s hunger signals. 

Why are you less full?

First the 100cal packs have less volume.  Volume plays a big role in being full, just as quality nutrition does. 

For example, you could drink one of your favorite flavored lattes as Starbucks (16oz Grande size) for and approximate 250 calories OR you could eat 3 cups full of spinach. Both have the same calories. Exclude the taste difference and the fact that eating 3 cups of straight up spinach does not sound all that great, you can imagine how eating three cups of spinach will make you much more full for longer than one Starbucks Latte.

Second, the chemical engineering of processed food purposely prevents you from feeling full or satisfied.  If you have not read the iconic Dorito’s article, you should.  Reader beware, you may feel manipulated, deceived, and angry by the end. 

3. You will have a loss of muscle mass

Muscles need quality macro and micro nutrients to grow and thrive.  Eating processed crap, even if low calorie, will reduce the amount nutrients going to your muscles, causing them to shrink, become less tight or “toned,” and weaker. 

I’m not saying eating quality food will make you look like a jacked gym rat bro but I am saying that not eating quality food will make you look soft, flabby, or “skinny fat.” 

4. You will have lower energy levels 

You will have lower energy levels because poor quality calories provide poor energy options for your body.  As a result, increased body fat even with reduced “calories.” 

In a study done in 2010 where participants were each given cheese sandwiches – one being process and the other being more whole – they found that digesting the whole food took 46.8% more energy to digest on average than processed food. So same calories in, but more calories out.  More energy out than in means…you guessed it…weight loss.

So What Do You Do?

Stop calorie counting, so looking at calorie amounts, stop worrying about calorie burn rates on your treadmills.  Just ignore calorie numbers.

Instead, eat a macro balanced diet of whole, non-processed foods most of the time (80% or so).

If you do, you will find you have plenty to eat (maybe even have a hard time eating it all).  You will loose weight, look better, feel better, have more energy, sleep more soundly, save money (aka cooking more), be sick less often, etc. 

…side note… if you are looking to put on some weight same applies, the only thing that changes is the volume and ratio of  your macro nutrients. 

You will even find that eating healthy and balanced is not super restrictive and it is darn tasty!

Interested in incorporating Macro balance in your life along with fitness, habit change, and stress reduction? 

Then check out my Physical Wellness System over at Flex Fitness OT.

Learn More HERE

Sign Up HERE

I want to give credit to Precision Nutrition (of which I am a Certified Coach).  This article was derived from a number of their wonderful and excellently research articles.  Below is a list of the articles I used in creating this blog:

  1. Calorie Control Guide
  2. Calorie Restraint Fat Loss
  3. All About Dietary Displacement
  4. Calorie Counting
  5. Label Lies
  6. Problem with Calorie Counting – Calories In
  7. Problem with Calorie Counting – Calories Out
  8. Food Labels – Part 3
  9. Digesting Whole vs Processed Foods


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