Calculating accurate metabolic rate
I have decided to start getting specific in losing fat this summer. One of the first things I ran into was trying to figure out my base metabolic needs so I could run a calorie deficit in a manner that would not affect my training. I know there are alot of you who read widely on this and am looking to see if anyone has information either more specific or more current than what I am looking at.
My first need is to calculate my resting metabolic rate(RMR). I was also wondering if anyone knows how much of a role (and effort) I should give to figuring out my thermal effect on feeding. In looking for my RMR, I find lots of general calculations based only on height/weight/gender but do any of you know where I can get more specific information. If I understand it correctly, my fat cells have a very low to non-existent metabolic demand. Should I calculate my RMR based off of my actual body weight or my lean body weight? Will the difference b/w the two have any effect on my training preformance?
I have read through the threads that I could locate addressing this, but I did not see anything that addressed a more focused RMR calculation. My apologies if there is one, feel free to direct me to it as my search function yields results that don't seem to relate to my keywords!
Comments
The best way to get your metabolic rate is to have it measured. This should cost under $100. You can search "resting metabolic rate measurement" + your city and see what comes up. The formulas are just guesses. I wouldn't worry about the Thermic Effect of Food.
If you can't get your RMR measured, I would use Mifflin-St. Jeor. If you know your body composition from underwater weighing or BodPod, I would use Cunningham. I WOULD NOT use body comp from calipers or bioelectrial impedance for this.
How I calculate calorie needs for clients is take the measured (or estimated) RMR and multiply it by an activity factor based on how active they are outside of workouts. If they sit at a desk all day, I use 1.25. If they are super active and moving all the time, I'll go as high as 1.9. Then, subtract an amount for weight loss (500 for 1 lb/week is conservative and shouldn't cause problems with training intensity). Then, add on calories for workouts. There are generally different levels based on the day - lower during the week, higher on weekends. I also say that you can move 300 - 500 calories around from day-to-day if you need it.
Calories per day = (RMR x activity factor) - 500 + calories for workouts.
Hope this helps!
As for activity factor, would you classify a job where I am standing for about half the day to be about 1.3-1.4?
Calipers are only accurate if you have someone very, very skilled doing them. I don't trust them unless it is done by someone who has received extensive training in doing it and has lots of practice under their belt.
Are you just standing or are you walking around?
Feel free to correct my (sometimes very poor) memory! If you still have that link, I think it would be good.
I don't remember that article, but your conclusions are correct. BodPod, underwater weighing, and DEXA are the best. I'll see if I can find it.
As for the calipers, the people pinching adminster the test about 50+ times a week. I know some are better known for the accuracy than others and generally seek them out. I do know they have to be reasonably accurate a skinfold test that exceeds certain standards will be grounds for dismissal from training and we have had it upheld to challenge before. But with all thats been discussed, I am going to try to call in a favor to get into the BodPod.
Sounds like you have some good caliper people. It would be interesting to compare what they get with the BodPod. :-)
Could you tell me more about how you adjust a client's calories based on exercise? Specifically, do you do it by daily activity, or some longer term number?
I've done it both ways personally. I'm an avid calorie counter (have been since losing 220 pounds 3 years ago). I use livestrong and right now I use my RMR * 1.2 as a base, and then add activity calories for the day to determine how much I eat. This is great on long bike days, it's really hard on rest days, when I go from 4000 calories to 2000.
I've also figured out a week in advance before, and averaged those calories out over the week, to make every day consistant. It's more comfortable on rest days for sure, but I've put on some weight doing it so I'm reluctant to do that.
I've considered adopting a third option, averaging a portion of everything over the 7 days and giving myself some extra room for big day fuel on the weekend bikes and thursday runs.
What do you think?
Do you have problems eating all the calories you your 4000 calorie days?
I think part of the caliper problem is that even with experience folks doing the measurement, ultimately the numbers are plugged into a formula that makes certain assumptions about global fat distribution that may or may not be correct.
FWIW, the Bodpod calcualtion of my RMR was within 50KCals of what I had already estimated using the calculator on Lose It.
Yes, I do have a problem eating all the calories on those big calorie days, so I do what you describe above occasionally...moving a few hundred calories forward for the next lower volume day. Thanks for the information...very interesting. I'm at about 9% bf now, and I'd like to move a little lower, but my body really really likes 9% for some reason. The line between loosing weight and performing poorly is pretty thin for me at the moment.