Training & Nutrition - Calories burned calculators: which bodyweight to use?

The Calories Burned Calculators that you find on the Internet all require you to enter your bodyweight. However, it doesn't specify which kind of bodyweight: lean mass, total, specific bodyweight %?

i.e. I'm pretty sure a 200lb bodybuilder with 5% bodyfat will burn more calories than a 200lb couch potato with 35% bodyfat.

So what number should I plug into those calculators? Does it assume, say, 15% bodyfat? So should I first find out what my lean body mass is then divide by .85 to get the right number to plug into the calculator?

It depends upon what kind of calories-burned you're calculating. If you're figuring out calories burned during a workout, then put in your true body weight. If you're calculating calories-burned for maintaining body-heat, you'd want to enter a slightly larger number to account for faster heat-loss (you've got less insulation). Overall, there's a great amount of inaccuracies in these calculators anyway because everyone's body, efficiency and fitness is different. I'd guesstimate that they're accurate to +/-20% at best.

People always overestimate their calories burned and underestimate the food they eat.

hmmmmmm i've never thought of that... i just always put in my actual body weight... even though i have a lower body fat (i do lift weight so have some muskel!)

of course... since i'm small... i know i don't burn the calories that guys burn... plus i've been working out and my body has gotten too efficient so that i don't burn a lot of calories....

i do measure my food to make sure i don't overeat (ok... it doesn't always work!)

but i agree... most people do underestimate their food (how many of you actually eat ONE serving of meat... that's 3 oz!!!!! lol!)

People always overestimate their calories burned and underestimate the food they eat.

Not always.

Today, I did a metric century on my own while rev'ed up on an ECA stack. It felt harder than the last century I did last weekend, due to a headwind on the leg back home and the effects of the stack.

According to my Timex HRM, I averaged 147 BPM for the entire ride, peaked at 172 BPM (my max on the bike is 186 BPM), and burned 3,710 Kcals.

My BMR for my age and weight is about 1,556 Kcals and the only thing I had before the ride was a cup of grape nuts granola cereal in skim milk and a banana--approximately 550 Kcals. During the ride, I had 2 x 24 oz of Gatorade--160 Kcals per bottle. After resting, I had a can of chili, another banana, and a protein drink--830 Kcals.

So, here's what my "energy" day looked like mathematically:



BMR Activity (Kcal) Total (Kcal)
1556 plus 3710 equals 5266
Factor equals 3.4

Food (Kcal) equals 1700
Debt (Kcal) equals 3566 1.02 pounds



So, according to the above, I'm about 1 pound down for the day, if I have nothing more.

Realistically, I'll probably have something else, but it won't be over the 3,566 Kcal debt. I can confidently say that today, my energy expenditures will be greater than my energy intake even if the BMR and Activity calculations are little off.

The reason I'm watching my weight isn't because of a race... no, I'm going on vacation in Cancun. I want to look good im my Speedo. :p :rolleyes:


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The Calories Burned Calculators that you find on the Internet all require you to enter your bodyweight. However, it doesn't specify which kind of bodyweight: lean mass, total, specific bodyweight %?

i.e. I'm pretty sure a 200lb bodybuilder with 5% bodyfat will burn more calories than a 200lb couch potato with 35% bodyfat.

So what number should I plug into those calculators? Does it assume, say, 15% bodyfat? So should I first find out what my lean body mass is then divide by .85 to get the right number to plug into the calculator?

I don't think that the calculators are accurate enough for it to matter. Heart rate monitors will give you a better estimate.

Not always.
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Yeah yeah... you're not estimating. You're actually counting.

Me, I ate at least 3000 kcals at dinner tonight. :D

Yours truly,

Fatty McWhycan'tIlosemygut

Is there anywhere to put in your bodyweight and heartrate to calculate calories burned online, ie perform the work that my ****ty heart rate monitor pretends it can do?

Neither would be very accurate anyway. Your HR @ 160-170bpm for an hour would represent the kind of work your body can do in its current fitness shape. Compare the same HR to a beginning rider would show them to burn off fewer calories. Compare your numbers to Lance @ 160-170bpm would show he's burning off mroe calories. The only way to accurately determine calories-burnt is to actually measure it. Put a rider in an isothermic chamber and measure how much he heats up his surroundings...

Yeah yeah... you're not estimating.
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blah, blah, blah

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They're all estimates--the calculation for BMR, expended calories derived from an algorithm embedded in the Timex HRM, and the calories assigned to foods from nutritiondata.com. None is exact.

Neither would be very accurate anyway. Your HR @ 160-170bpm for an hour would represent the kind of work your body can do in its current fitness shape. Compare the same HR to a beginning rider would show them to burn off fewer calories. Compare your numbers to Lance @ 160-170bpm would show he's burning off mroe calories. The only way to accurately determine calories-burnt is to actually measure it. Put a rider in an isothermic chamber and measure how much he heats up his surroundings...

In the absence of an isothermic chamber, it's the best one can do to track energy input and output on some consistent and convenient basis.

And, it's apparent from my before and after pics, that my method is doomed to failure :rolleyes: :

http://img.photobucket.com/albums/v285/NoRacer/contrast3.jpg

Is there anywhere to put in your bodyweight and heartrate to calculate calories burned online, ie perform the work that my ****ty heart rate monitor pretends it can do?

The problem with such a tool is that it's not taking into consideration the work being done as it changes with intensity due to external (temp, terrain, wind, position on the bike, etc.) and internal factors (hydration status, fitness level, thermoregulation, etc.)

An HRM can sample heart rate at intervals and apply the inferred work load to an algorithm that approximates kcals burned.

The problem with such a tool is that it's not taking into consideration the work being done as it changes with intensity due to external (temp, terrain, wind, position on the bike, etc.) and internal factors (hydration status, fitness level, thermoregulation, etc.)

An HRM can sample heart rate at intervals and apply the inferred work load to an algorithm that approximates kcals burned.
http://www.kreuzotter.de/english/espeed.htm

Takes into account wind, grade, speed, type of bike and the only thing it doesn't take into account is HR

If you want to lose weight, enter the body weight you WANT to be. There's no point entering your current body weight ... that would only work if you want to MAINTAIN your body weight. Plus, because most people overestimate their calories burned and underestimate the food they eat, entering a lower weight would give you a more accurate reading.