Joining us today is **biologist Dr. Matthew Papaconstantinou**. Matthew received his PhD in Medicinal Chemistry and conducted postdoctoral research for 5 years in the field of blood biochemistry at Washington University School of Medicine in Saint Louis, MO.

Matthew is an avid windsurfer who lives in the beautiful seaside village of Aktaio, Greece. He often goes mountain biking and hiking in the majestic Greek mountains.

**WeightLossTriumph.com** is a blog where Matthew reviews the latest diet trends, compares clinically studied weight loss programs (such as Weight Watchers, Medifast, and Nutrisystem,) and often publishes interesting scientific findings in the fitness and nutrition fields.

He has a very different approach than I do (likely due to my severe lack of scientific background,) so this will be an interesting change of pace! Get ready to crunch some numbers!

**Coach Levi: I’m always getting emails from endurance athletes wondering how many calories they’re burning during each workout. Why is it important to know the calories burned when running, biking, or swimming?**

**Dr Matthew Papaconstantinou:** People who watch their diet (athletes, weight watchers, dieters, etc.) want to know how much energy they consume when they perform various activities. Knowing your Total Daily Energy Expenditure (TDEE), whether you are an athlete or someone who wants to manage their weight, allows you to structure your nutrition plan so that you will achieve your body weight goal.

**Coach Levi: OK, let’s jump right into it – how can we calculate the calories we burn when we ride? Or during any endurance sport, for that matter?**

**Dr Matthew Papaconstantinou:** Well, we first need to understand that the question of “how many calories cycling burns” is as vague as the question “how much fuel does a moving car consume”. A Hummer H3 model 2007 burns 18l/100km (13mpg) in the city and 15/100km (16mpg) on the highway while a Nissan Qashqai 2012 – that’s the type of car I own by the way – burns only 6l/100km (39mpg) in the city and 5.2l/100km (45mpg) on the highway. Cars are different and so are humans.

Exercise physiologists have found that the amount of calories you burn performing any physical activity depends on the following factors:

- Your age. Are you a 2007 or 2012 model? Obviously, your grandma will not burn as many calories as you if you both run 1 mile
- Your gender. Are you a Hummer or a Nissan? You and your girlfriend or boyfriend do not burn the same when bicycling.
- Your weight. Definitely, I don’t burn as many calories as 325lb Shaquille O’Neil.
- Your body composition (percentage of fat mass and muscle mass). Is your engine a 3.5 liter/320 hp or a 1.6 liter/130hp? The more muscular you are the more you burn. Four time Mr Olympia, 250 lb bodybuilder Jay Cutler burns more calories than almost any of us when bicycling!
- Other physical and environmental factors such as your fitness level, cardiovascular health, and ambient temperature.
- Other factors not yet discovered.

As you can see, when it comes to calculating the calories burned bicycling, you need to realize that:

- Since the above parameters (age, fat free mass, etc) are unique for each person, the amount of energy we burn bicycling varies among individuals.
- Calculating the exact energy you burn is a very complicated process. Of course, there are certain apparatuses used in laboratory settings that can accurately calculate an individual’s energy expenditure by analyzing the volume of expired air, but these methods have limited practical interest.

**Coach Levi: It’s starting to sound pretty complicated! How does the average person, without a lab, figure out how many calories they’re burning?**

**Dr Matthew Papaconstantinou:** In order to simplify the calculation of the energy expended in physical activities, scientists have come up with a measure called Metabolic Equivalent of Task (MET). One MET is the energy an average person burns at rest per kilogram (kg) of body weight per hour (h). In other words, 1 MET is the calories 1 kg of resting human tissue burns in 1h. It is also known as the Resting Metabolic Rate (RMR.)

“Rest” is the state of doing no physical activity – for example, when we sit quietly. The “average person” refers to a healthy 40-year old, 70kg (154lb) man.

Therefore, by convention **1 MET = 1 kcal / kg x h**.

The MET concept gives us a rough, but practical and sufficiently accurate, estimation of the energy we spend performing various activities. The beauty of this method is that it bypasses the requirement for complicated measurements (i.e fat free mass, fitness level). Each physical activity is assigned a number of METs. Essentially, with the introduction of MET concept, the rate of energy we spend performing various tasks is expressed as a multiple of our RMR. For example, a physical activity that has 2 METs requires twice the energy we spend when we rest. A task that has 5 METs burns energy 5 times faster than our RMR, and so on.

Sports physiologists have calculated the MET values for many sports and daily physical activities. Here are the MET values for running, swimming, and biking at different speeds copied from The Compendium of Physical Activities Tracking Guide.

Activity |
METS (kcal x kg^{-1} x h^{-1}) |

running, 5 mph (12 min/mile) | 8.0 |

running, 5.2 mph (11.5 min/mile) | 9.0 |

running, 6 mph (10 min/mile) | 10.0 |

running, 6.7 mph (9 min/mile) | 11.0 |

running, 7 mph (8.5 min/mile) | 11.5 |

running, 7.5 mph (8 min/mile) | 12.5 |

running, 8 mph (7.5 min/mile) | 13.5 |

running, 8.6 mph (7 min/mile) | 14.0 |

running, 9 mph (6.5 min/mile) | 15.0 |

running, 10 mph (6 min/mile) | 16.0 |

running, 10.9 mph (5.5 min/mile) | 18.0 |

swimming laps, freestyle, fast, vigorous effort | 10.0 |

swimming laps, freestyle, slow, moderate or light effort | 7.0 |

swimming, backstroke, general | 7.0 |

swimming, breaststroke, general | 10.0 |

swimming, butterfly, general | 11.0 |

swimming, crawl, fast (75 yards/minute), vigorous effort | 11.0 |

swimming, crawl, slow (50 yards/minute), moderate or light effort | 8.0 |

swimming, leisurely, not lap swimming, general | 6.0 |

swimming, sidestroke, general | 8.0 |

swimming, synchronized | 8.0 |

bicycling, BMX or mountain | 8.5 |

bicycling, <10 mph, leisure, to work or for pleasure | 4.0 |

bicycling, general | 8.0 |

bicycling, 10-11.9 mph, leisure, slow, light effort | 6.0 |

bicycling, 12-13.9 mph, leisure, moderate effort | 8.0 |

bicycling, 14-15.9 mph, racing or leisure, fast, vigorous effort | 10.0 |

bicycling, 16-19 mph, racing/not drafting or >19 mph drafting, very fast, racing general | 12.0 |

bicycling, >20 mph, racing, not drafting | 16.0 |

In order to calculate the amount of calories you burn when you perform a certain activity for a certain period of time you must multiply the MET value for that activity by your body weight and by the duration of the activity.

Energy Expended (kcal) = MET x Body Weight (kg) x Time (h)

So, based on the above table and the fact that I weigh 83 kg, the calories I burn if I run for half an hour at 5mph are:

Calories Burned Running = 8 x 83 x 0.5 = 332 kcal

**Coach Levi: Looking at the table, I see that MET depends on the speed of the activity. Does this mean we burn more calories when we run faster?**

**Dr Matthew Papaconstantinou:** This is a topic I would like to touch upon and thank you for bringing it forward. Indeed, if you look at how the MET values of a certain activity (i.e bicycling) change as a function of the intensity (speed), you will notice that MET—the rate of energy expenditure—is directly proportional to the intensity of the activity.

What does this mean?

Well, there is a common misconception here. People mistakenly extract the conclusion that if we run a certain distance at higher speed we will burn more calories than if we run the same distance at a slower intensity. This fallacy is the result of confusing the meaning of MET. The value of MET signifies **rate** of energy expenditure. It’s not energy expenditure. MET equals the amount of energy burned per unit of time. The faster you perform your activity the higher the MET value because higher speed means you are burning energy at a higher rate.

In light of this, you burn more calories per minute if you perform an activity fast compared to performing the activity slow. But if you perform an activity for a set distance, you burn the same amount of calories irrespective of the speed! Here is an example:

Suppose you run 1 mile at 5 mph. You burn the same energy as when you run 1 mile at 10mph. In fact, you would burn the same amount of calories if you just walked that 1 mile! The only difference is that it will take you more time to complete 1 mile the slower you run.

**Coach Levi: So, does this mean that when we run 1 mile at 5mph we spend energy at half the rate but for twice the time comparing to running at 10mph, so that in the end we have burned the same amount of energy?**

**Dr Matthew Papaconstantinou:** That’s exactly right. Here are the numbers to your example: When you run 1 mile at 5mph, you spend energy at a rate of 8 kcal x kg^{-1} x h^{-1} for 12 minutes. When you run 1 mile at 10mph, you spend energy at a rate of 16 kcal x kg^{-1} x h^{-1} for 6 minutes.

**Coach Levi: Looks like we are dispelling a common myth here! As far as calories go, speed is not a factor when running, swimming, or biking – distance is.**

**Dr Matthew Papaconstantinou:** Correct. The energy you burn depends on the distance, not the intensity. Hard to believe, huh?

**Coach Levi: I can’t argue with the numbers! Now here’s something else that can be confusing. You mentioned RMR, but I’ve also heard of BMR. Are they the same thing?**

**Dr Matthew Papaconstantinou:** While RMR and BMR do not refer to the same thing, practically they can be used interchangeably because their arithmetic difference is usually very small. As mentioned, RMR is the rate your body spends energy when resting – sitting on a couch without doing anything.

Basal Metabolic Rate (BMR) refers to a more strict condition whereby your body is at complete rest – a hypothetical coma-like state where the energy your body spends is the bare minimum to keep you alive. Experimentally, BMR is measured in a darkened room, after 8 hours of sleep, and a 12-hour fast to ensure the digestive system is inactive.

Obviously, BMR is a little smaller than RMR. You can better understand the difference between BMR and RMR if you look at the MET values of sitting quietly and sleeping. The MET value when you are reclining doing nothing (riding in a car, listening to music, watching TV), without talking or reading, is one. The MET value for sleeping – a state resembling the complete rest condition – is 0.9.

**Coach Levi: OK, that clears that up! It’s really neat to see the technical difference between the two (even if I never get my true BMR tested.)**

**Now let’s also talk about the concept of Total Daily Energy Expenditure. How can we calculate our TDEE? Is there a formula for this as well?**

**Dr Matthew Papaconstantinou:** Absolutely. Knowing our TDEE is the most important piece of information when we are trying to gain muscle mass or burn fat and lose weight. The balance between the calories you consume and the calories you burn each day is the ultimate determinant of your body mass. The popular Points System used by the wildly successful weight loss program Weight Watchers is nothing but a modified calorie-based approach to dieting. Here is the formula for calculating the calories you burn in one day.

TDEE = Total Daily Energy Expenditure

TDEE = BMR x PAL

(Remember, BMR = Basal Metabolic Rate and PAL = Physical Activity Level.)

To find TDEE we first need to calculate BMR and PAL. The quickest and most accurate way to determine BMR is by using the Mifflin St Jeor Equation.

According to this formula, a 36-year old man who weighs 183 lbs and is 5 feet 10 inches tall would have a BMR of 1768. In fact, that’s my BMR. I would burn 1768 calories a day if I did nothing—just sitting quietly on bed. Of course, like you, I’m an active person. I work in my office, go shopping, cook food, lift weights, clean my house, ride my bike, etc. In order to determine my TDEE I must calculate the energy I spend separately doing all these individual activities one by one and add it to my BMR. That’s nearly impossible.

This is why exercise physiologists have introduced the concept of PAL – a way to get you and me out of this difficulty. Instead of calculating the caloric cost of each of all my small or big daily chores, work, leisure and sport activities, I just multiply my BMR by a number that expresses the intensity level of my daily activities. This number ranges from 1.2 to 2.4. The one that best represents my lifestyle is 1.7. (I’m moderately active.)

Activity Level | Example | PAL |

Sedentary | Little to no exercise, desk job | 1.4 |

Moderately active | Running 1hr daily | 1.7 |

Vigorously active | Swimming 2hr daily | 2.0 |

Extremely active | Competitive cyclist | 2.4 |

TDEE = 1768 x 1.7 = 3005 calories per day.

I can safely eat 3000 calories every day without gaining a pound. If I want to lose fat, I will eat less in order to create a caloric deficit. If I want to gain weight, which in fact is my goal as an amateur body builder, I have to adjust my nutrition so that I will create a caloric surplus.

So, there you have it. Using the above equations we can estimate pretty accurately the energy we burn performing various endurance sports. We can also determine the total energy we burn in one day, and construct our diet plan around our calorie needs in order to meet our fitness goals.

**Coach Levi: I’m no math whiz, but that sounds like a straightforward calculation! Thanks Matthew – we now know how to calculate our true calorie needs so we can achieve ideal body composition and racing weight!**

Any questions? The comments section is now open!

*Are you an endurance sports expert who wants to be interviewed here on CoachLevi.com? Send me an e-mail with your bio and we’ll talk.*

My RMR is 1666 and my daily calorie needs (TDEE) are around 2,300 calories. I am a runner and I want to keep my weight as is. Thank you for making it clear that I spend the same amount of calories when I run my 3 miles a day, regardless of the speed.

Hi Steven,

you are welcome! Indeed, few people are aware of this concept. Of course, I need to clarify something here. The higher the intensity the greater the “after burn” effect–that is the increase in energy expenditure above resting levels for a limited time after we exercise. So, while running a mile at 5mph may have the same energy expenditure as running a mile at 7 mph, the latter increases your metabolism (post exercise) above resting levels to a greater extent than the former resulting in a higher calorie burning.

Thank you for stopping by.

Do you disagree with your previous advice?

http://coachlevi.com/training/hours-not-miles/

@Wendy

Not at all! But you make a very important point!

Just to clear up any confusion, keep in mind that this interview focused on calorie expenditure (rather than training plan design.) There are certainly reasons to run at different speeds for different time periods depending on your goals.

@Wendy

Indeed, as Levi points out in that article (http://coachlevi.com/training/hours-not-miles/), when it comes to training goals (ie. improving endurance, cardio training, etc) the riding conditions do matter. Distance is not the only factor here. The following conditions play out:

– Terrain (i.e. Climbing.)

– Intensity.

– Weather (cold, rain, wind, etc.)

Time.

– Drafting (lack of wind resistance.)

Dr. P16

If you have ever ridden a bicycle you’d know that riding at 5mph for a mile does not burn the same calories as doing it at 15mph. Overcoming wind resistance at 5mph is essentially 0, but at 15mph it is huge. So your energy expended is really dependent on intensity when you have to overcome a higher wind resistance at increased intensity.

@Lars

Unless you’re in a testing lab on a stationary bike! ðŸ˜‰

Hi Matthew and Levi,

I weigh 110 kg (242 lb) so I calculated that I burn 440 calories when I bike for half an hour at 12mph. Awesome! I need to lose weight and I have decided to establish a 800 calorie deficit. Half of it will come from daily exercise (like biking) and the other half from my diet. My TDEE is around 2400 calories and my goal is to eat only 1500 a day.