Evaluating Daily Caloric Needs - (This contains math!)

gp79

It's been 3 months since joining MFP. Since joining I've really learned alot. I've been through the whole, "do I eat my exercise calories or not" and understand the math that's going on behind the scenes.

MFP uses the MD Mifflin / ST Jeor method for determining BMR, which is one of three available formulas for determining BMR. Harris Benedict has been marked as overestimating BMR, especially in overweight subjects. The third is Katch McArdle, which I'd never heard of until recently. Supposedly it's more accurate if you know you're body fat percentage.

Katch McArdle states that BMR = 370 + ( 21.6 * Lean Body Mass in kg )

In order to solve the equation we need to know what our Lean Body Mass is. I set out to determine this today, by means more accurate than any online calculator or equation (James / Thume). I bought a set of calipers to do a self test and had my body fat analyzed by an Omron Body Fat Analyzer (one of the ones you hold with both hands out in front of you). Keeping in mind I'm not a pro in doing the caliper test, especially on myself, I did my research, watched some videos and read the instructions so I'm sure I was "fairly" accurate in my results.

Accu - Measure Calipers - 24.5% (+/- 1%)
Omron BF Analyzer - 21.3% (+/- 3%)

(Note: I'm still not satisfied with the results of the test. My buddy took the test after I did, we changed the information to reflect his statistics and his BF% was analyzed as 24.9%. My buddy is Marine, Army Ranger, has great Genetics and in excellent shape. Much more defined than I am and works out 2x per day, most days)

I took the average of the two measurements and figured my LBM to be 22.9%

The equation for solving for Lean Body Mass is
LBM =(Body weight in kg * ( 100 - Body Fat Percentage ) ) / 100
LBM= ( 108.64 * ( 100 - 22.9 ) ) / 100
LBM= 83.76 kg or about 184.27 lbs

Back to Katch McArdle....

BMR = 370 + ( 21.6 * Lean Body Mass in kg )
BMR = 370 + ( 21.6 * 83.76 )
BMR = 2179

This figure is only slightly off of MFP's MD Mifflin figure of 2122 calories. Negligible.

Now I need to account for my activity level. I exercise 4-5 days per week but otherwise my activity level is taking care of a household, office work and I travel about the country 120 - 180 days per year. My workouts burn anywhere from 500 - 1200 calories, as monitored with a HRM. To simplify having to have a different caloric intake daily based on if it's a workout day or a rest day, I assumed I am moderately active, multiplying my BMR by 1.5.

2179 * 1.5 = 3269 calories <

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Maintenance calories

To lose 1.5lbs per week I need to subtract 750 calories.

3269 - 750 = 2519 calories


Question - By taking a more simplified approach, will spreading the calories out over the week slow my progress? ie. the days which are rest, I'm essentially consuming 'some' exercise calories.

Up until now I've been setting MFP to Sedentary to account for my daily activities other than exercise, be it light office duty, showering, talking, household duties etc. and then adding in my exercise calories based off of what my HRM records during my workouts. This has been working for me, but as I'm beginning to better understand the process, I want to further simplify it all so at some point, I'm not necessarily having to wear a HRM. Eventually one day when my phone breaks or MFP implodes, I want to be able to do this on my own and not be forced to use the MFP security blanket, albeit cozy.

chrisdavey

I like this post

mideon_696

As do i...

iamthepreston

Good post. I see you have done a little homework.

How many sited did you pinch? 7 is the most accurate. Also when you pinch be consistent with the spacing of thumb and index finger regardless of the site. Also note you can not pinch muscle. You might have already known this.

As far as eating an average amount of calories over the week I do not know what is best. I doubt one is any better than the other. Doing it by the day leaves less room for error, but this isn't purely scientific anyway. I do know on some days if I am hungry and almost out of calories I will do 20 minutes of cardio so I can eat more. It is a little incentive I use.

ohohraptor

Could you post some links that go through the steps of getting your % with the calipers? I have been toying with the idea of getting a pair, since the scale isn't all the accurate for me anymore.

chrisdavey

Take your skinfold's at certain points. I do chest, abdomen and thigh and use this http://www.linear-software.com/online.html

Seems too good to be true for me but as long as I measure consistently then mm don't lie

emariec78

Interesting post! I've been wondering about this same thing! I have no idea what the answer to this is from a medical/scientific standpoint but I can tell you my own experience that I am having more success using the daily amounts as opposed to spreading the calories over the week. I had been at the same weight for months monitoring a steady calorie intake and in three weeks using the daily amounts I've lost 2.5 lbs.

gp79

It's like christmas morning, waking up to a bunch of replies to a post I made late last night. I've gotta drive across Georgia today but I'll reply later tonight with some links I found.

Thanks everyone.

ohohraptor

Take your skinfold's at certain points. I do chest, abdomen and thigh and use this http://www.linear-software.com/online.html

Seems too good to be true for me but as long as I measure consistently then mm don't lie

Awesome, thanks! Does the kind of caliper matter much? There seems to be a huge difference in prices online.

gp79

I remember seeing a youtube video last night comparing the Accu Measure calipers to the so called "fake" versions. I didn't watch it but maybe look for it.

All the caliper is doing is measuring in mm, the thickness of the fold. The pair I bought were like 15 bucks. Not too steep.

chrisdavey

Take your skinfold's at certain points. I do chest, abdomen and thigh and use this http://www.linear-software.com/online.html

Seems too good to be true for me but as long as I measure consistently then mm don't lie

Awesome, thanks! Does the kind of caliper matter much? There seems to be a huge difference in prices online.

Mine are ebay cheapies. They appear to measure ok? I don't think there would be much difference. Unless you want to be fancy and get digital ones :P

lmcadoo

Thanks so much! This was so helpful. I just began this journey 3 days ago and already had this question pop into my head. So, if I can simplify a little bit, (BMR * 1.5 (activity level)) - 750(1.5lbs/week)= maximum daily caloric intake for weight loss. Or I totally missed it altogether. LOL

suziehomemaker

bump

gp79

Or you could go even simpler, and multiply your body weight by 15 to get your maintenance calories, then adjust for weight loss.