Warning to never eat below your BMR?

I get confused about eating/not eating below my BMR as well, but mainly because I have gotten a range of answers from different BMR calculators. I've been told anywhere from 1900-2150. I know it's just an estimate but it's making me confused about what my calorie intake should be. MFP has it at 1820 (to lose 1lb a week) but that seems low. I originally had it at 2000 but even that is considered low if my BMR is actually over 2000. I have a lot of weight to lose so maybe I don't need to worry about eating under BMR as much? I'm not sure.
Confused. LOL

I wouldn't worry about your BMR. Just pick a deficit that seems reasonable to you and take it off of your TDEE (or just use MFP).

If your BMR is 1900 to 2150 and you are sedentary, then you'd have a TDEE of 2280 to 2580. If you are more active, it would be higher. If MFP tells you to eat 1820 to lose 1 lb a week, that means it is estimating your maintenance (without exercise) at about 2320, which is perfectly consistent with that range.

If you are happy losing 1 lb/week, I'd start with the MFP number and see what you actually lose and then adjust. Remember that the way MFP works is that you add back in your exercise calories or some reasonable amount of them, which is yet another reason why worry about whether your BMR is below your MFP goal seems an unnecessary complication. A deficit of 500 when you have a lot to lose is not overly aggressive for most people.

Thanks

Argh, I'm still finding the concept understanding of BMR and TDEE really overwhelming (is that stupid?!) It makes sense, but I don't get it? Although I pretty much still eat at mostly below my minimum calorie goal, I stopped losing any thing ages ago. But, I'm scared that if I increase to boost weight loss again, then it'll pile back on? *confused face*

Pile what back on?

Water or fat?

What if you knew the first big amount of weight loss was purely water weight (which it was) - would that matter?

What if you knew you do cardio outside in summer your blood volume will increase with more water - would it matter?

What if you knew you were depleted in normal muscle carb stores, with attached water, maintaining a false lower weight that would go back up when you ate normal - would it matter?

Or do you rather care about losing fat? Fat from places that people see, inches, no matter what it might happen to weigh?

TDEE is literally a daily thing, and MFP actually uses that method.
They start with non-exercise TDEE basically, maintenance. Take a deficit off. Because you merely need to eat less than you burn to lose weight.
But when your exercise, your real TDEE for that day goes up by whatever you burned in exercise. Take the exact same deficit off that now bigger number, and you obviously eat more.

But in both cases - you are eating less than you burn, each day, exercise or not.

BMR, what you body burns for basic functions of metabolism (all day burn is NOT metabolism), is the life sustain functions.
You got muscles helping you breath, muscles pumping your heart, brain using energy (more when awake), growing hair/nail/skin? You are burning those calories all day long.
You also burn calories processing food, from the muscles moving it along, to the breaking it down and transporting it.
You also burn more calories when you wake up and start moving.
And of course if you go out and purposely exercise.

Add all that up - that's TDEE, which obviously is very variable daily, but you can estimate a rough amount.

MFP just leaves the exercise out of that list until you really do it. Then you log it, TDEE goes up, you eat more.

So here's a fun test, because you are obviously eating at maintenance right now. Whether that be whatever number you think your are, or include the binges that may happen because it's so low, or add on for the inaccuracies in bad food logging.
You are eating at maintenance right now.
But is it suppressed maintenance because your body didn't like what you were doing to it, or potential maintenance and your numbers are just terrible estimates?

Eat 250 more calories daily for 2 weeks.
Guess how much you gain slowly if you were already eating at true potential maintenance?
1 pound. Reread that.

If you gain more or faster, then it's obviously water weight, because fat can't go on that fast eating a mere 250 more.
What that does prove though, is your body is still getting less than it wants, and it has you with depleted carb stores in the muscles, which stores with water.
You eat 250 more for 3 days and gain 1 lb, you just increased those carb stores.
Good, needed, normal, carb stores. If you think it's bad weight, then you should bleed yourself too, because there is likely unneeded blood volume with extra water weight too.
Foolish thinking on both parts though.

You may also gain none - which means your body increased it's daily burn to match what you are feeding it - meaning prior eating level was obviously not potential maintenance or TDEE.

xxhalokitty, you have a BMI of 19 and you are stil ltrying to lose weight?
Why?

I have eaten below my BMR (by approx 200 calories) and lived to tell the tale.
I did this for 2 weeks at a time, AND exercised 5 days per week during this phase.
Worked REALLY well for scrubbing fat.

I may try this again, although I would keep it to Short Controlled Bursts, and not just because it's an awesome album. (Google will help with my non-sequitor). Eating below BMR would likely be tough on a body if done for an extended period of time, although I have no actual proof on which to base this idea....

^^This seems right to me.

Wow there is a lot of posts on this questions and a lot of good (and bad) responses. Here you go folks-

There are 4 main areas of weight management:
Weight Gain- eating more than your TEE (Total Energy Expenditure)
Weight Maintenance- eating equivalent to your TEE
Weight Loss- eating ABOVE your RMR/BMR (Resting Metabolic Rate/Basic Metabolic Rate) but BELOW your TEE
Starvation Mode- Eating BELOW your RMR/BMR

Consistently eating below your RMR means your body is not getting enough calories to operate organs so it will generally burn MUSCLE calories to make up the difference. In addition, you metabolism will SLOW DOWN to compensate for the lack of calories until the intake matches the output. This generally means your body fat may go down slightly, your weight will go down (your are decreasing muscle weight) and your inches will go down (again, muscle decline). This looks GREAT to someone who doesn't know better, BUT, the end result is a decrease in muscle and a rapid decrease in metabolism= NOT GOOD!

Advice: Find a comfortable calorie window between your RMR/BMR and your TEE and you will LOSE WEIGHT while MAINTAINING lean body mass (muscle).

You WILL NOT know what your true RMR/BMR is until you have it tested so go do it!!

Intermittent fasts are fine, it's the consistent lack of calories over time that's the issue.


Credentials: Bachelors in Nutrition and minor Human Biology and I've been practicing for 8 years

You can eat below your BMR and you'll be fine... I've done so myself when wanting to lose the last few pounds...

As you lose weight, you need less calories...

I would calculate my TDEE and subtract 250 to 500 cals from that number... Try that for 3 weeks, if you aren't losing weight make sure you are calculating your calories correctly (weighing all food on a scale)... then, if you're counting calories correctly and still not losing weight, subtract another 250...

I would also consider, doing cardio (HIIT is my favorite) and adding weight training to increase your TDEE...

I forgot about the never eat below BMR fad. I have no idea why someone created an account to give advice on a three year old thread, but nostalgic.