Wednesday, January 25, 2006

RMR - Resting Metabolic Rate

Well, I figured since I 'flaunted' around RMR (Resting Metabolic Rate) that I should go ahead and prove my theory. There are many scientific calculations for your RMR. They vary a bit, but I just took the least amount for my purposes. (If you want to find a calculator, simply Google 'calculating resting metabolic rate' and a bunch of calculators will come up.)

What is RMR? It is the amount of energy (calories) that your body requires at rest. In other words, if you don't do anything but sit around and breath, this amount of calories are required by your body to function.

There are things that affect your RMR - the amount of muscle you have (this is why you want to preserve as much muscle mass as possible - in fact, adding muscle mass would even be better!); your age (boo!); your sex (of course, guys burn more. mainly because they have a higher muscle mass naturally); climate (the colder the climate - the more energy the body needs to keep warm - but hello, who is really exposed enough to the elements for this to have a real impact?); small regular meals (supposedly).

Oh, I should mention that RMR is also referred to as BMR - Basal Metabolic Rate. There is really no difference. So use whichever one you want. But I see some differences? There are like 5 different calculations that are commonly used to determine RMR / BMR - therefore you can see up to a 50 calorie swing depending on which calculation is used.

Using one of the calculators, my body at its current weight requires 1634 calories at rest. Remember that is with no exercise - this is your body at rest.

1634 RMR/BMR x 7 days = 11,438 calories expended per week

(**Assuming 1000 calorie diet/day on average**)
1000 calories x 7 days = 7,000 calories consumed per week

Calories In - Calories Out = Weekly Deficit
7,000 cals per week - 11,438 cals per week = -4438 calorie deficit

Translation - 4438 divided by 3500 calories in a lb = 1.3lbs

Bottom line - I should be losing at least a lb a week. My overall average shows this weightloss.

Bad news is that as you lose weight your RMR / BMR goes down -- assuming constant muscle mass. Why? Well it all boils down to there is less of you to support at rest. It takes less calories to support 150lbs than 200lbs. What to do? Any combination of: Eat less, move more, gain muscle mass.

Hopefully someone found this interesting! :o) It was a good exercise for me to remind myself that as long as I am patient - the weight WILL drop off.


Jessica said...

Yes, very interesting. When I was working with a personal trainer last year, I actually did a BMR test to find out exactly what MY BMR is. You breathe into this machine out of your mouth with your nose clipped shut (so you don't breathe out your nose) and then it gives a fairly accurate reading. She recommended coming back and having it done again after I lost weight.

Serena said...

Thanks, anything that reminds us to be patient is a good thing. Also it is good to be reminded that eating less isn't necessarily better.