Is it healthy to eat below BMR?! Help!

XGorgeous007

Hey everyone so I have been researching caloric deficit and was wondering if eating below your BMR would do more damage than help in weight loss? Anyone currently doing this? I'm trying to determine how to create a good deficit with 1734 BMR but this gets confusing with intake plus exercise calories! If anyone has advice I would kindly appreciate it!

Daisy xo

seska422

BMR is just a number to use to calculate other things like TDEE. BMR isn't an important number by itself.

Your body will use alternate energy sources to get up to TDEE so you need to have enough excess fat to accommodate that. The less excess fat you have, the smaller your deficit should be.

rileysowner

Assuming you measure your food properly and use the correct database entries you should be able to lose eating your BMR. The more important number is your TDEE if you are looking to set your calorie goal manually. Whether eating below your BMR is unhealthy or not is sort of difficult to say. However, eating at an excessively low goal can result in various negative things (excessive loss of lean mass, sense of deprivations, bingeing, and the like).

Advice, either use the MFP numbers with a weight loss goal appropriate for the amount of weight you need to lose. Eg. Under 20 pound to lose no more than .5 of a pound a week. 20-50 about 1 pound a week. Over 50 you could probably do 1.5 to 2 pounds a week. Or, go to a TDEE calculator and taken 15-20% off that number which would include intended exercise. With the MFP number you would eat back at least a portion of your exercise calories.

PAV8888

Many sources consider a caloric deficit equal to no more than 20% of your TDEE (up to 25% while obese) to be suitable for controlled long term weight loss.

Through the magic power of definitions (sedentary at MFP is set at 1.25x BMR + you are supposed to eat back exercise calories) and math... a goal like that will almost always have you eating at or above BMR.

ninerbuff

Depends on how much you have to lose. People who are very overweight or obese can easily eat under their BMR. Those who are close to their ideal weight with not much to lose, not so much.

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chastity0921

You could eat below your BMR, but why would you want to? You could eat at your BMR and still lose weight. Just remember that this is long-term, and you don't want to be miserable.

peter2100

I aim to eat just at my BMR.

WinoGelato

Hold up. Your BMR is 1734? What are your stats OP? Height, weight, activity level...

That seems high for BMR for a female, essentially the number of calories needed to keep you alive if you were in a coma. Where did you get that number from?

thunder1982

I found this BMR calculation online For women, it is 447.593 + (3.098 x your height in centimeters) + (9.247 x your weight in kilograms) - (4.33 x your age). Mine worked out to be 1664 for 1 35yp 161cm female currently weighing 94kg. So I dont see that 1734 is all that high.

Sued0nim

What's your height and weight

That BMR sounds wrong

Sued0nim

And in answer to your question BMR is irrelevant to calorie setting beyond the fact it's a building block in establishing TDEE

Eat sufficient calories to meet your nutritional requirements through a wide diet
Find foods you enjoy within your calorie limits

trigden1991

BMR is an arbitrary number and cannot be measured or calculated.

mommasplash

I'm a woman, 5 ft 3, I currently weigh 216 and my BMR is 1732 (Scooby's calculator). I have about 90 lb to lose. I try to eat at least my BMR calories every day as a minimum, otherwise I feel deprived, and I do enough exercise to give me a deficit of 200-500 cals daily. That seems to be working very well for me at the moment. I use the calculator after every 10 lbs lost, to make sure I know what my BMR is at the new weight, as this number will get progressively lower.

lemurcat12

Sued0nim wrote: »

And in answer to your question BMR is irrelevant to calorie setting beyond the fact it's a building block in establishing TDEE

Eat sufficient calories to meet your nutritional requirements through a wide diet
Find foods you enjoy within your calorie limits

This is correct.

BMR is an estimate, and is merely supposed to be what you'd need to maintain if you didn't move at all beyond the bodily functions keeping you alive. Your body doesn't know if you are over it or under it and you will never know what it actually is. ESTIMATED BMR is a useful building block to estimating TDEE (your maintenance calories given the activity you actually do), and it makes sense not to cut too much off of TDEE. If you are sedentary or have a lot to lose or some combination of those, eating below BMR may be recommended or no big deal.

Another issue is that there are a variety of ways to estimate BMR and some aren't as accurate for people who have a lot to lose. The best one is probably McArdle-Katch, but it requires body fat percentage which is useful to know. The reason is that muscle burns a lot more than fat and without the BF% the other ones will work better for someone who has a more average BF% (or really a more fit one). So I think BMR and TDEE can be overestimated for people with lots to lose, although that often gets offset on MFP by the fact that people claim "sedentary" activity rate when they are not (and when overweight general active that is being ignored when you say "sedentary" often burns lots of calories).

Anyway, a good example of the range are the numbers given just above:

Scooby says 1732 for someone 5'3, 216, but if I assume 50% BF% and use McA-K, it gives only 1430 for BMR, which is likely closer to correct. (That said, I started around those stats and consistently lost more than predicted -- eating less than my BMR usually, however -- because I think I was underestimating activity.)

SusanMFindlay

IMO, BMR is a better estimate of "minimum calorie intake that will give you body the nutrients it needs" than the blanket 1200 (for women) that gets thrown around a lot. That's because the BMR factors in height and weight. And as long as you're not in a coma, you will lose weight eating your BMR. If you're active, you need to eat more than that, but that's another discussion.

That said, no, eating slightly below BMR is not likely to cause health problems. I just don't see why you'd want to.

This all assumes that we are genuinely talking about BMR not TDEE. Clearly, you have to eat below TDEE to lose weight. It also assumes accurate tracking of calorie intake. If you underestimate, you may need to aim for a lower apparent number so that your actual number is in a good range.

trigden1991

SusanMFindlay wrote: »

IMO, BMR is a better estimate of "minimum calorie intake that will give you body the nutrients it needs" than the blanket 1200 (for women) that gets thrown around a lot. That's because the BMR factors in height and weight. And as long as you're not in a coma, you will lose weight eating your BMR. If you're active, you need to eat more than that, but that's another discussion.

That said, no, eating slightly below BMR is not likely to cause health problems. I just don't see why you'd want to.

This all assumes that we are genuinely talking about BMR not TDEE. Clearly, you have to eat below TDEE to lose weight. It also assumes accurate tracking of calorie intake. If you underestimate, you may need to aim for a lower apparent number so that your actual number is in a good range.

But how do you calculate an individuals BMR without putting them in a coma?

yarwell

trigden1991 wrote: »

BMR is an arbitrary number and cannot be measured or calculated.

Of course it can be measured or the concept of predicting it based on measured data wouldn't exist. It is nothing to do with a coma either. Time for some reading perhaps.

red99ryder

For what it's worth . MFP has me set less than the BMRS I have looked at online .. set to lose 1.5 per week and been pretty spot on for 5 months

Good luck

SusanMFindlay

trigden1991 wrote: »

SusanMFindlay wrote: »

IMO, BMR is a better estimate of "minimum calorie intake that will give you body the nutrients it needs" than the blanket 1200 (for women) that gets thrown around a lot. That's because the BMR factors in height and weight. And as long as you're not in a coma, you will lose weight eating your BMR. If you're active, you need to eat more than that, but that's another discussion.

That said, no, eating slightly below BMR is not likely to cause health problems. I just don't see why you'd want to.

This all assumes that we are genuinely talking about BMR not TDEE. Clearly, you have to eat below TDEE to lose weight. It also assumes accurate tracking of calorie intake. If you underestimate, you may need to aim for a lower apparent number so that your actual number is in a good range.

But how do you calculate an individuals BMR without putting them in a coma?

Use the estimates you can find using online calculators. Yes, they're estimates - but they're better estimates than just telling everyone to "stay over 1200" (or 1500 if they're male). For someone who's 6' tall, that's way too low and for someone who's 4'8, they could safely go a little lower.

And once you've used it as a starting point, listen to your body and adjust if necessary.

(And I'm pretty sure the omnipresent 1200 number came about because it was an approximate BMR for a small older woman.)

rileysowner

SusanMFindlay wrote: »

trigden1991 wrote: »

SusanMFindlay wrote: »

IMO, BMR is a better estimate of "minimum calorie intake that will give you body the nutrients it needs" than the blanket 1200 (for women) that gets thrown around a lot. That's because the BMR factors in height and weight. And as long as you're not in a coma, you will lose weight eating your BMR. If you're active, you need to eat more than that, but that's another discussion.

That said, no, eating slightly below BMR is not likely to cause health problems. I just don't see why you'd want to.

This all assumes that we are genuinely talking about BMR not TDEE. Clearly, you have to eat below TDEE to lose weight. It also assumes accurate tracking of calorie intake. If you underestimate, you may need to aim for a lower apparent number so that your actual number is in a good range.

But how do you calculate an individuals BMR without putting them in a coma?

Use the estimates you can find using online calculators. Yes, they're estimates - but they're better estimates than just telling everyone to "stay over 1200" (or 1500 if they're male). For someone who's 6' tall, that's way too low and for someone who's 4'8, they could safely go a little lower.

And once you've used it as a starting point, listen to your body and adjust if necessary.

(And I'm pretty sure the omnipresent 1200 number came about because it was an approximate BMR for a small older woman.)

From what I have read the 1200 is considered by most health organizations as the minimum calories needed for a woman to get the necessary nutrients she needs for health. Thus eating below that for a long period of time brings the danger of nutritional deficiencies and the associated health problems. It has nothing to do with BMR. This is not to say a woman could not meet her nutritional requirements under 1200, but it would require actually considering what she is eating to make sure she is getting nutritional foods.

JeromeBarry1

The idea of damaging your metabolism arises from your body adapting to a persistently severely lower calorie intake. "Persistently" is going to be more than 7 consecutive days. "Severely" is going to be a deficit of more than 500 calories per day. "Lower" is going to be lower than your NEAT, your Non-Exercise Activity Thermogenesis.
As BMR is the least calories you will burn comatose, NEAT is the least calories you will burn going about your activities of daily life. The longer you persistently and severely force your NEAT to adapt to deprivation, the longer it's going to take to restore your NEAT to a normal (for you) rate of burn. The good news is that the adaptation to a month of low-calorie intake can be reversed with just a day or two of calorie intake above your adapted NEAT, and 6 months of adapted NEAT can often be fixed with just a couple of weeks of daily calorie intake above your adapted NEAT.
The only real problem any of us have is that measuring accurately our NEAT is expensive and difficult. The adaptation that has been measured in good study facilities has been about 10% reduced or increased by either under or over eating.

Caution, the published stories of the most severe deficits to NEAT, such as the contestants on The Biggest Loser, indicate that some individuals adapted NEAT never return to normal. That's a line you'd be wise to avoid approaching.

WalkingDeadFrank

Many great points have been said throughout this post...

BMR is just a formula to help you figure out your TDEE. I know my TDEE cuz I use a Garmin fitness watch throughout the day and during my exercises, so there is no need for me to look at BMR.

It can be that simple.

Frank

SusanMFindlay

rileysowner wrote: »

SusanMFindlay wrote: »

trigden1991 wrote: »

SusanMFindlay wrote: »

IMO, BMR is a better estimate of "minimum calorie intake that will give you body the nutrients it needs" than the blanket 1200 (for women) that gets thrown around a lot. That's because the BMR factors in height and weight. And as long as you're not in a coma, you will lose weight eating your BMR. If you're active, you need to eat more than that, but that's another discussion.

That said, no, eating slightly below BMR is not likely to cause health problems. I just don't see why you'd want to.

This all assumes that we are genuinely talking about BMR not TDEE. Clearly, you have to eat below TDEE to lose weight. It also assumes accurate tracking of calorie intake. If you underestimate, you may need to aim for a lower apparent number so that your actual number is in a good range.

But how do you calculate an individuals BMR without putting them in a coma?

Use the estimates you can find using online calculators. Yes, they're estimates - but they're better estimates than just telling everyone to "stay over 1200" (or 1500 if they're male). For someone who's 6' tall, that's way too low and for someone who's 4'8, they could safely go a little lower.

And once you've used it as a starting point, listen to your body and adjust if necessary.

(And I'm pretty sure the omnipresent 1200 number came about because it was an approximate BMR for a small older woman.)

From what I have read the 1200 is considered by most health organizations as the minimum calories needed for a woman to get the necessary nutrients she needs for health. Thus eating below that for a long period of time brings the danger of nutritional deficiencies and the associated health problems. It has nothing to do with BMR. This is not to say a woman could not meet her nutritional requirements under 1200, but it would require actually considering what she is eating to make sure she is getting nutritional foods.

The idea that every woman of every size needs exactly the same amount of every nutrient to maintain health is absurd. A larger person needs more protein, more fat, more iron, more calcium, more vitamins, more everything (at least, larger in terms of 'more lean body mass'). The public statements that the health organizations make are intentionally oversimplified so as to not intimidate or overwhelm the public.

I have seen exactly zero science supporting the 1200 number. It's a nice convenient round number that's easy for people to remember. It's low enough to provide a deficit to almost every woman but high enough that it won't starve the average woman. And if you looked at the BMR of a smaller older woman and rounded to the nearest multiple of 100, 1200 is what you'd get.

It doesn't magically get easier to get all your nutrients in when you cross from 1199 to 1201. It's easy to eat well over 1200 and not be getting adequate nutrition. 1200 is just a convenient number to remember that is, frankly, at least slightly too low for the majority of women.

All of which is why, in my opinion, using an estimated BMR value as your 'don't eat less than this in order to get adequate nutrition' value is ideal. The estimated BMR factors in your height, weight and age - all of which contribute to how much of each nutrient you actually need in your diet. (And, yes, if you're incredibly sedentary, you might need to drop your calories a little below that level - but you should then pay even closer attention to making sure that your diet consists of mostly nutrient dense foods.)