Is a calorie burned the same as a calorie eaten?

Suppose you are on a strict diet of eating 1700 calories per day.

One day you relax and have a can of Coke, adding an extra 140 calories to your intake.

A few hours later you feel guilty and hop on the treadmill. You run until the calories burned reads 140 calories.

Will the exercise net out the extra calories you just ate? Why or why not?

(Assume the treadmill calorie count is accurate).

Calories burned vs net calories burned

I am not a health professional, but speaking mathematically I can say the calories do not net out.

The reason is the following: most treadmill calorie counts are TOTAL calories burned. They include not just calories from running, but also the amount of calories burned by your base metabolic rate–the calories you would have burned if you had just sat around on the couch.

As exercise for weight loss is about burning extra calories, we are interested in the marginal calories burned.

Basal metabolic rate

At the risk of being overly focused on the numbers, you can use this calculator to find your basal metabolic rate:

Discovery Health calculator: http://health.discovery.com/centers/heart/basal/basal.html

Find your basal metabolic rate based on your gender, weight, and height. Then you divide by 24 to see how much you are burning per hour in a day when you are just resting.

For example, if your basal metabolic rate is 1800, then that means you are burning 75 calories an hour (1800/24). (This might vary depending on time of day or if you are sleeping, so take this number as an approximation)

Treadmill calories burned

Now let’s return to the treadmill. Suppose you walk for half an hour and the treadmill says you have burned 140. But you know that includes your basal metabolic rate of burning calories. If you had sat around, you would have burned about 38 calories.

That means you only burn an extra 102 calories from the exercise–not enough to make up for the 140 calories from Coke.

Don’t take this too seriously

These are all approximations and I am sure health issues are more complicated. I am definitely ignoring a lot of biochemistry going on and I’ll be honest about that. I’m sure someone can point flaws in my argument or perhaps point out some useful diet/exercise resources.

Still, I think it’s a good idea to realize exercise calorie numbers are often inflated. Just as a dollar saved is better than a dollar earned (because of taxes), this article shows how it can be the case mathematically that a calorie not eaten is better than a calorie burned.



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  • anomdebus

    I also think there is uncertainty about what percentage of calories consumed are absorbed. Though in this case, the calories from the coke probably reach the limit of digestibility.

  • Chris

    You’re forgetting about the opposite side of the equation. How many calories are burned in digesting the extra calories ingested. Its the same principle on the other side of the equation.

  • http://nehakhaitan.blogspot.com Neha

    But out of the 140 calories, you would have anyways burned a minimum of 38 calories doing nothing. So what remains of the 140 calories of the coke is 102. So if you burn out 140 on the treadmill you are making up for the 140 you consumed. Makes sense???

  • Christopher Chow

    Fascinating, never realized that exercise equipment included basal metabolic rate for that time exercised.

    Gonna have to agree with Neha on this one though. Calories burned by your basal metabolic rate are still consumed and her math is sound.

    The key is whether or not the total calories you ate the rest of the day was less than, equal to, or greater than the total calories your BMR accounts for. This will affect whether you will be net positive for the day (and whether your 30 minutes on the treadmill makes up for the coke).

    A better way to illustrate the point you wanted to make in your post would perhaps be like this:

    Assume BMR = 2400 calories per day (i.e. 100/hr)
    Your daily diet (as an OCD test subject) is exactly 2400 calories and is delivered to your door daily and includes all meals.

    Imagine now: you want to drink a 140 calorie serving of coke.

    Will using the treadmill for 0.5 hours (which happens to be until the treadmill reads 140) make you gain weight?

    in 0.5 hours your basal rate is 50 in this example.
    So in that half hour you only burned an additional 110 calories rather than a full 140 — and so you for the 24 hour period are still net positive 30 calories.

  • http://www.twitter.com/onsomeshit Adam22

    I lack the scientific knowledge to be specific here, but I once read that cardio isn’t all about the actual calories burned. It’s also about doing activities that release hormones in your body that encourage fat burning long after you’re done exercising, help to build muscle etc. Anyone who goes for a 30 minute run knows that your body feels different for hours after, it has a great effect on your mindstate etc.

    Either way… exercise is about a lot more than just burning calories.





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