calories used but how many?

HelenM · #1 (**permalink**) 08-19-2008, 11:17 AM

After reading about Michael Phelps's calorie intake. I tried to work out how many calories I actually use/need. After a run on the treadmill, it says I've used 681calories, input the time/distance into sportstrack my running log, it reduces it to 493, an online calculator is more optimistic 560 but runners world suggests it was only 460.
Multiplied by a weeks running thats a huge variation, add in other activities like gardening, walking and housework, who knows what the actual calories used are!
I'm not really asking a question but if there are these discrepances in one activity I think its highly unlikely that anyone can accurately calculate their daily calorie output using internet tools.

GeishaGirl · #2 (**permalink**) 08-20-2008, 10:05 AM

Calories as a whole are an inaccurate form of measurement anyway. If you think you know, for a fact, how many calories you're taking in in any given day, you're wrong.

Take my favorite microwave burritos (before diagnosis at least). They were 360 calories -- but that's only an average. If the ratio of beans/rice is different, the calories are different. Was the cheese densely or loosely packed? All of that makes a big difference.

I have a Forerunner for my exercising, and the calorie burn is considered low. After a walk on the treadmill, it'll say i burned 112, but the treadmill will say 178. OTOH, it says I burn around 950 cals/hour rollerblading, which seems ridiculous, since I can blade for several hours at a time.

Point being, it's all an estimate. ANYTHING having to do with the body is an estimate, you know? The human body is art, not science

volleyball · #3 (**permalink**) 08-20-2008, 10:30 AM

At that rate of consumption, I bet his percentage of calories actually being absorbed by his body to be low. With that flood of food, a lot will flow through undigested.
No mass market exerciser or website will give truly accurate predictions. A non runner plodder will use more energy than a person who has been running well for a long time and is used to it and has good form. I think those machines who rate higher would also sell better as some would think they are better because if you run on machine a for a mile and burn 100 cal. and machine b burns 120 cal. for the same speed, it must be better