How Many Calories Are You Really Burning?



This week’s Fitness Post is brought to you by personal trainer Igor Klibanov from Fitness Solutions Plus.  

After a full hour jog, you look on the treadmill, you check the number of calories burned, and the magic number is 637 calories. Not bad for an hour on the treadmill. But how accurate is this? Let’s examine this.

First of all, what is a calorie? A calorie is a measure of the amount of energy it takes to heat up 1 milliliter of water by 1 degree Celsius. Put simply, it’s basically a measure of energy.

Now what affects how much energy you expend? Here is a list just off the top of my head: age, fitness level, speed, total weight, fat-free weight, muscle mass, speed of metabolism, incline, heart rate, hormones, clothes you’re wearing, temperature in the room, and even your thoughts during the time you are on the treadmill. This list is far from complete, but it’s a good place to start.

Just to give a quick example of how different people will burn different amounts of calories. Let’s say you have 2 women, both of them 40 years old, both of them 1.62 metres tall (5’4), both of them weigh 150 lbs. and they are both walking at 3.5 miles per hour. One woman has 15% body fat, whereas the other woman has 35% body fat. In other words, everything is identical except for this one factor. Do you really think both women will burn the same number of calories? Heck no!

Another example: Let’s say you have 2 men, both of them 50 years old, both of them 1.77 metres (5’10 or so) tall, both weigh 180 lbs, and both of them have 12% body fat. They are both jogging at a speed of 6 miles per hour. One of them has a heart rate of 170 at this speed, and the other one has a heart rate of 130 at this speed. In other words, one of these men is expending significantly more ENERGY (that is, calories) to maintain this pace than the other. But in the end, what does the number on the treadmill (by the way, this also applies to ellipticals, exercise bikes, rowing machines, stair climbers, etc.) say for both of them? That they burned the same number of calories.

Since most treadmills only ask you for your age and weight (and the better ones will measure your heart rate, but won’t take that into account when calculating calories), is there any chance of predicting the number of calories burned that’s even close to accurate?

What About Calories Taken In?

Just like you really don’t know how many calories you’re expending, you also have no idea how many calories you’re taking in.

Sure, you might know how many calories are going in your mouth (although even that is questionable), but you really have no idea how many calories are absorbed by the body (not all calories are absorbed).

For instance, a 200-pound person with hypothyroidism can be taking in 800 calories per day and still gain weight. At the other end of the spectrum, a type 1 diabetic can eat 10,000 calories per day, without gaining weight (that is, without insulin injections).

This is an extreme example, but it’s not limited to pathological states.

Here is a short list of factors that affect how many calories you extract from your food:

  • Your body temperature. You use food for heat. At a temperature of 36.5-36.8, your body is working properly. For every degree that your body temperature is under this range, you’re burning 20% fewer calories.
  • The strains of bacteria in your gastrointestinal system. An experiment was done on rats. They took the bacteria from fat rats, and put it into thin rats. Without any changes in the rats’ diet or exercise, thin rats gained weight. They did the opposite as well. Fat rats lost weight. Again, without any changes in nutrition or exercise.
  • Your hormonal status. If you have insulin resistance (and many of our clients have it without knowing it), you’ll have a hard time losing weight. If you have a slow thyroid, low testosterone, low leptin, etc., you’ll have a hard time losing weight.
  • Your brain chemistry. If you have insufficient amounts of serotonin, you’ll have a hard time losing weight.
  • Toxins. The more toxic you are, the more calories you’ll extract from your food.

Again, this is just scratching the surface, and there are many more factors that will affect your ability to lose fat.

So what’s the overall message? Stop counting calories. You don’t know how many are going in. And you don’t know how many are going out.

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