BMR Seems WAY Low (for MFP Mathematicians)

DogRiverDude

Based on Calories Consumed vs. Weight Lost, my calculated BMR appears to be quite a bit lower than it should be.
--> I'm just curious to see if anyone else has noticed the same??

RAW DATA:
- 70 days
- BMR 2,037 (a running 70-day average as calculated on MFP)
- Calories Consumed = 82,726 (net after exercise)
- 46.2 Pounds Lost

CALCULATIONS:
Calorie Deficit = (2037 Avg. BMR x 70 days) - (82,726 Consumed) = 59,864
Theoretical Loss if 3,500 calories is 1 pound = 59,864 / 3,500 = 17.1 pounds
Actual BMR = [(46.2 x 3,500) + 82,726)] / 70 = 3,492

a) Could my BMR actually be 3,492 (making my daily calorie deficit a whopping 2,310) or...
b) Is there exercise that I'm not accounting for (like simple day-to-day tasks) or...
c) Could I be underestimating the "real" exercise calories burned or...
d) Am I diseased and dying (just joking... er, sort of!) or...
e) some combination thereof?

*** Should mention that I feel great and have no known medical issues (other than high blood pressure at my max weight).

DeguelloTex

BMR is just from being alive. Unless you've been in a coma, that's not the proper measure of how many calories you burn in daily activity.

StaciMarie1974

BMR is just what your body burns to keep you alive. Organs to function, digest food, maintain body temp, etc. You also burn calories for activity (to move thru your normal daily routines) and during intentional exercise.

If you consumed 82726 in 70 days, that's an average of 1182 per day. If you lost 46.2, I'd first assume some was water weight. So going from 40 (just to make it a round #) means a deficit of about 2000/day so burning ~3200.

That doesn't mean your BMR is 3200. It means your TDEE on average was 3200. It also means you probably lost a good bit of muscle mass in that time frame so its perhaps wise now to increase your intake, and work on a strength training program.

malibu927

Your BMR is what you burn just by living and is based on your age, height, and weight. When people lose weight, they go by their TDEE, which is your BMR multiplied by a factor based on your activity level and then take a percentage off of that.

Men are not recommended to eat less than 1500 a day. You're averaging just below 1200, which is the recommendation for women, which is why your loss is so high. You've lost a tremendous amount of weight because of that, but because it's so much you probably lost quite a bit of muscle.

StaciMarie1974

Ps-you can look up BMR which is based on height/weight/gender/age thru any search engine. In general guys do have higher BMR than gals. Which also means they tend to burn more thru exercise. My husband (200 now, on his way to 170ish) can easily burn 4000 in a day by being very active, lots of cardio. I may hit 3000 at the same level of activity, but could not possibly do 4000.

senecarr

DogRiverDude wrote: »

Based on Calories Consumed vs. Weight Lost, my calculated BMR appears to be quite a bit lower than it should be.
--> I'm just curious to see if anyone else has noticed the same??

RAW DATA:
- 70 days
- BMR 2,037 (a running 70-day average as calculated on MFP)
- Calories Consumed = 82,726 (net after exercise)
- 46.2 Pounds Lost

CALCULATIONS:
Calorie Deficit = (2037 Avg. BMR x 70 days) - (82,726 Consumed) = 59,864
Theoretical Loss if 3,500 calories is 1 pound = 59,864 / 3,500 = 17.1 pounds
Actual BMR = [(46.2 x 3,500) + 82,726)] / 70 = 3,492

a) Could my BMR actually be 3,492 (making my daily calorie deficit a whopping 2,310) or...
b) Is there exercise that I'm not accounting for (like simple day-to-day tasks) or...
c) Could I be underestimating the "real" exercise calories burned or...
d) Am I diseased and dying (just joking... er, sort of!) or...
e) some combination thereof?

*** Should mention that I feel great and have no known medical issues (other than high blood pressure at my max weight).

Like everyone else seems to say, I think you have BMR (basal metabolic rate) mixed up with TDEE (Total Daily Energy Expenditure).
There's also the possibility that if this 70 day average is from when you first started losing weight, a chunk of the weight is water weight, or depending on if you do any resistance training, it could even be muscle. While fat is estimated to have 3,500 calories per pound, a pound of muscle only stores around 1,200 calories I believe, and water obviously stores 0 calories.
If you had a BMR around 3,492, chances are you wouldn't have ever had 40 lbs available to lose. There is a woman who is considered to have 0% body fat from a condition, and I believe her BMR is estimated at 4,500 calories.

TimothyFish

If you have been losing 4.62 pounds per week, you're not eating enough. It is likely that much of that is lean body mass, so the normal 3500 calories per pound won't give you an accurate result.

malibu927

This thread will explain it all better: community.myfitnesspal.com/en/discussion/931670/bmr-and-tdee-explained-for-those-needing-a-guide

DogRiverDude

THANK YOU everyone for your detailed responses! They've been very helpful!! The TDEE read was great.

Weight loss was extreme at first at 9.0 lbs / week but has steadily decreased and is currently sitting around 3.0 lbs / week (perhaps still a little high for my current weight). I'll bump my calories 300 to the minimum recommended 1500. I doubt the 300 additional calories will create any issues. Thanks again :-)

girlviernes

Even 1500 is probably quite low given your rate of weight loss. I would say 1800 as a minimum and make sure you are getting sufficient protein.

DogRiverDude

girlviernes wrote: »

Even 1500 is probably quite low given your rate of weight loss. I would say 1800 as a minimum and make sure you are getting sufficient protein.

Yes, looks like you're correct.

My TDEE appears to be (depending on the method calculated) 3200-3600. Ironically (well, actually "not" ironically) the "3,492" number I calculated falls very close to the middle of that range!!! Theoretically, and assuming my exercise levels remain consistent, I can consume 2,492 calories per day and still lose 2 lb / week. I'll give 1800 a try and adjust as required after a couple weeks.

EDIT: Protein and Nutrients aren't currently an issue (I track these numbers as well).