Phoenix Ignition Fitness Company

Fitness by the Fire: The Truth and Purpose of Calories

by Ron Kennedy • January 14, 2019
There are many misunderstood scientific terms regarding health and wellness. I am writing this article within the second week of January, and with the New Year’s fitness rush already underway I have no doubt search engines like Google are being flooded with fitness related key word searches. “Weight loss, muscle building, fat loss diets” near endless terms from an ocean of people seeking solutions for their fitness needs. These people have the best intentions to make dynamic change with their physical lives, but as my wife states and frequently reminds me “The pathway to hell is paved with good intentions” and along with the samplings of genuinely good information there is a copious amount of misinformation, marketing strategies intertwined with key word searches to expose you to a health related project, as well as flat out lies. As a fitness professional, I have spent a significant amount of time in my career dispelling this misinformation, and I wanted to pick a very common topic that I feel most everyone can take something away from to start the new year. The meaning and purpose of calories.

Most people who care about their bodies know about or have at least heard of calories. We know we are supposed to count them, certain foods have more than others, and if you take in more calories than you use you gain weight, but if you use more calories than you take in you lose weight. These statements are true in their own right, but they really just scratch the surface in regards to the effect calories have on us not just within fitness, but our lives as a whole.

The exact definition of a calorie is the energy needed to raise the temperature of 1 gram of water through 1 degree Celsius (or 4.1868. Yikes… I am a science major and that barely makes sense to me. Let’s try another one; A unit equivalent to the large calorie expressing heat-producing or energy producing value in food when oxidized in the body. I think we can all agree that seems a bit more relatable. To put it in laymen’s terms, calories are a measurement of heat needed to raise the water temperature in our bodies to breakdown food into energy.

If you look at the 3 primary source of food we ingest, proteins, carbohydrates, and fats, each food has its own value as to how many calories it requires to process (burn) 1 gram of each of the group. In addition each sub-group uses a certain amount of energy to eat the food from that group. Take celery for example. It’s strange why it is listed to have negative calories right? That is because celery is literally solid water in food form and actually costs more energy to consume it than is within the vegetable its self!

Protein: Protein takes the most energy to digest. On average about 25-30% of the total calories from protein is used to consume it. To keep it simple, were you to eat 100 calories of protein it would take about 30 of those calories to digest and absorb the protein, which would leave you with a net absorbing of 70 calories. It requires 4 calories to burn 1 gram of protein, so a healthy male with a reasonably high protein diet (150 grams of protein) would spend 600 calories just to burn that 150 grams, and that doesn’t include the absorption process. Do you now see why I tell all you readers who train with me to eat your protein…????!!!!   

Carbohydrates: Carbs require far less calories to digest, typically 5-10%. That is not a good thing considering how much the body earns for sugar and doesn’t use a large amount of energy to process it. Have you ever wondered why a bowl of pasta or a heavy sandwich makes you feel good? Carbohydrates spike insulin levels which promotes the brain to produce serotonin. Serotonin is a “feel good” neurotransmitter that is responsible for sleep, mood, and even sex drive. Being from Chicago and loving my Bill’s pub pizza, I often describe it to those who have not sampled it as “being better than sex”, and know you why!

 Like protein, it requires 4 calories to burn 1 gram of carbohydrates. The primary reason for carbohydrate intake is to produce glucose, one of the main sources of energy in humans. Now let me be very clear, glucose is not a bad element as it is energy that can be used almost right away or stored for later if needed, but the problems come when people fill up on this energy and DO NOT USE IT! Our bodies are not designed like vehicles with fuel tanks. You fill up the tank on Monday and expect it to get you through the week right? That works for cars, but people are supposed to fuel every few hours and end the day with an empty tank. Not doing so leads us to our next and final group…

Fats: Fats require the least amount of energy to consume, 0-3%. Yeah, that’s right. That is a massive net consumption. If you take in 100 calories of fat, most of it is going right to the blood stream. To make matters worse, as opposed to proteins and carbs, it takes a whopping 9 calories to process 1 gram of fat, twice as much!

Fats do have their purpose in human health. Triglycerides, cholesterol and other essential fatty acids store energy, insulate us and protect our vital organs. Shockingly enough, fats assist protein molecules doe their job more effectively by being “messengers” between the cells. Fats also trigger growth, aide the immune system (if you have ever stayed consistent with a low carb low fat diet, you may have noticed it is much easier for you to get a cold) and even boost reproductive function.

Now that you have a fundamental understanding as to what calories are and what each type of calorie is used for, let examine how many calories you are burning during the certain activities. The following graph was created by USDA and is depicts a 5’10 154lb man during various exercises. Each exercise is measured by 1 hour and 30-minute intervals:
  Approximate calories used (burned) by a 154-pound man
MODERATE physical activities: In 1 hour In 30 minutes
Hiking 370 185
Light gardening/ yard work 330 165
Dancing 330 165
Golf (walking and carrying clubs) 330 165
Bicycling (less than 10 mph) 290 145
Walking (3.5 mph) 280 140
Weight training (general light workout) 220 110
Stretching 180 90
VIGOROUS physical activities: In 1 hour In 30 minutes
Running/ jogging (5 mph) 590 295
Bicycling (more than 10 mph) 590 295
Swimming (slow freestyle laps) 510 255
Aerobics 480 240
Walking (4.5 mph) 460 230
Heavy yard work (chopping wood) 440 220
Weight lifting (vigorous effort) 440 220
Basketball (vigorous) 440 220
This chart should give you a clear idea of the energy used during these activities and what effect they will have on your metabolic rate. The question I get asked the most a fitness professional is what is the most effect way to lose weight while building muscle. Regarding proper use of calories running stands as the clear winner, right?


Running does not build muscle, despite what every zealot runner might tell you. Running does force the muscles to perform, but it on dilates the muscle to create force, muscles do not grow in the sense of bulk and strength. Strength training is the most effect way to burn calories as well burn fat. Not only that, but lean muscle mass produces more raw heat (remember... calories are simply a measurement of heat) than fat or the lack their off, by miles!