BMR/RMR Accuracy

toeatandrun
toeatandrun Posts: 3 Member
in Health and Weight Loss
How accurate are BMR and RMR calculators? I've put my info into so many of them, and my average usually indicates that I can eat 2100 calories to maintain; however, I SWEAR I gain weight just by eating over 1500 calories.

Is this all in my head, or could I really just have a super low range for maintaining my weight? I'm trying to lose weight, so I'm struggling to find a balance... and, more importantly, I'm struggling to accept myself on days when I eat over my MFP 1500 limit. I feel like I'm going to gain no matter what if I go over that limit ...

The thing is, it doesn't make sense for me to. I do 40 minutes of kickboxing 5 times a week. I TRY to eat fairly clean. I do have binge eating disorder, which is a struggle some days ... but in general, I do my best to live a healthier lifestyle, especially now as I try to lose 15 lbs.

So basically, I'm asking: should I just trust what the calculators told me even though I truly feel like I gain weight whenever I eat 1700-2000 calories in a day?

Replies

  • ticklish_adam
    ticklish_adam Posts: 3 Member
    I'm in the same boat. The calculators I have found, say I should be in-taking 2511 calories a day, but I've been maintaining around 1113 a day. Also, MFP keeps telling me to take in more calories (well above 1200), but after a week of doing 'the 3-2-1 plan' and exercising rigorously for 30 minutes every 2 days, I seem to be losing weight, without feeling hungry or fatigued.
  • heybales
    heybales Posts: 18,842 Member
    The Harris and Mifflin (which MFP uses) are based on gender, age, weight, height.
    Mifflin considered about 5% more accurate than Harris, especially when overweight.

    The formula's are based on studies of healthy weight average ratio fat to non-fat mass participants. As such they start to inflate BMR as your weight increases.
    Unless somehow you managed to gain lots of muscle with lots of fat and kept the ratio the same - doubtful.
    So inflated.

    The Katch BMR based on weight and bodyfat % is same type of study.

    Same healthy weight, same average ratio of FM to FFM.

    But at least with that one, as weight increases, BF% normally increases, and it actually underestimates because all that extra fat actually does take energy to maintain, it just isn't accounted for.

    At healthy weight in the studies, I think they were 5% accurate for the 85-95% of the folks.

    It will be inflated as weight based on extra fat goes up, except for Katch and a decent estimate of BF%.

    To that BMR estimate add the fact you can suppress it slightly by eating with extreme deficit. Actually, the BMR/RMR doesn't suppress as much as the whole sedentary TDEE.
    http://www.myfitnesspal.com/blog/heybales?month=201401


    Add to that is the rough 5 TDEE levels, also from the Harris BMR study from 1919. Yes, 1919.
    It's been improved upon in many places.
    But is is multiplier to your BMR, so 2 places for inaccuracies to kick in. Bad BMR estimate, bad guess of TDEE level.

    But obviously it can't be that correct, there are only 5 levels, and your amount of daily activity and exercise together is totally variable.

    Be aware that as soon as you went in to a diet, you lost water weight.
    Some from sodium because most eat less as soon as they start logging food and watching what they eat.
    But also from not as much stored carbs, which stores with water. You'll gain that back as soon as you eat at maintenance.

    And you are likely weighing on invalid days, and merely watching water weight fluctuations.

    Always do the math if you think it's fat.

    You would have to eat 250 over your real TDEE, your daily maintenance, NOT your eating goal, for 2 weeks to slowly gain 1 lb of fat. And if good workouts, wouldn't even be all fat.

    Reread that.

    So if you gain 1 lb in 3 days eating 100 extra compared to normal - it is most obviously NOT fat, but water weight.
    Get used to that effect, or you'll have a miserable weight loss journey.

    How much weight do you gain, in what period of time.

    Oh, only valid weigh-in day unless you are willing to wait a month or more, morning after rest day eating normal sodium levels, not sore from the last workout.

    Anything else is a useless data point until you have a lot over a long period of time.

    Adam - what level are you going to start eating at when weight loss stops? What direction can you possibly move.
    Your not feeling hungry is really a useless feeling, as you've just screwed up hormones, that's all.
    http://www.t-nation.com/diet-fat-loss/truth-about-metabolic-damage

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