Warning to never eat below your BMR?

rosebette

Some sources (and even posters here) warn never to eat below your BMR. However, isn't it necessary to eat below your BMR to lose weight? For instance, my BMR is around 1300 (age 55, 5'1.5") and MFP puts me at 1200, which is hardly any deficit at all, but of course it's unsafe for me to go below that number. And someone who is say young, 5'1" and weighs 200 lbs might have a BMR between 1800 and 2000, but would it be "unsafe" for someone that overweight to eat below 1800 calories a day?

chadya07

your bmr is what you need to exist without doing anything at all. just laying around.

so unless you plan on sleeping your way thin, you need to eat at or above your bmr. your TDEE is the number of what you burn with existence and movement

something along those lines anyway.

i guess what i mean is, you need to eat below what you burn both moving and resting, not below what you burn just resting.

DeguelloTex

I eat below my BMR almost every day.

RHachicho

Eating below your BMR both is and isn't a good idea depending on your situation.

First let's get one thing straight. Your BMR isn't your total caloric need. Your BMR is what your body WOULD need if it where in a coma. Every time you so much as twitch you exceed your bmr. Now lets take two different cases.

Case one 6 foot odd man with 30% body fat. Fat can metabolize about 1600 calories a day all on its own. Long as he doesn't fill the whole day with strenuous crap this person could probably eat 1200 - 1500 cals and still be ok even considering hes a 6 foot odd man. His fat will make up the difference. And his body will get all the calories it needs to be healthy. And this is what a minimum calorie level is about being healthy.

Case two a 5 food odd man with 12% body fat who eats 800 calories a day trying to lose weight. His fat can probably generate about 3-400 a day his bmr is probably in the low 2000's so the total calories available to his body is now well below his bmr. BIG PROBLEM!

Your BMR needs to be fueled or bad things happen but it doesn't have to come from food. If you have a decent amount of body fat you can sustain larger deficits. However it is inadvisable to cut food beyond a certain level hence MFP's 1200 minimum. Some people could safely go below that but they are exceptions. If you have a decent amount of weight to lose then honestly eating 100 below bmr is probably not a big deal. IF you are skinny then yeah your headed up diarrhea drive without a paddle.

chadya07

deleted cause someone explained stuff better above me.

rosebette

But say if I weighed 220 instead of 120, that would mean that I shouldn't eat below 1800, yet that is the number of calories to keep a sedentary, overweight person at the same weight he/she currently is. Wouldn't it make sense for that person to eat less than that to lose?

chadya07

you dont need to worry about what other people need to eat or what you need to eat tomorrow. you base your numbers on where you are today. your BMR changes with your weight.

DeguelloTex

when you eat below your BMR your body gets its fuel from other places than just fat, lean tissue, muscle, even organs if you go long enough and far enough below.

No one's talking about doing it concentration camp style.

I have about 80 pounds of fat. At 31 calories per pound per day, metabolizing my organs probably won't be an issue for quite a while.

chadya07

But say if I weighed 220 instead of 120, that would mean that I shouldn't eat below 1800, yet that is the number of calories to keep a sedentary, overweight person at the same weight he/she currently is. Wouldn't it make sense for that person to eat less than that to lose?

maybe i am misunderstanding your question but BMR is not maintainance. 1800 is not what an overweight person needs to stay the same. it is below what they need to lose weight. however, that number is based on the fact that it tales a larger person more energy to survive. the smaller you are the less you need, so the less you need to eat in calories. each person has their own BMR based on their stats, its not a one size fits all. you need to eat less than you burn in a day counting your movement/exersize. not more or less than someone else eats.

(edited because i want to say not every overweights BMR is 1800, its just an example)

Liftng4Lis

Eating below your BMR both is and isn't a good idea depending on your situation.

First let's get one thing straight. Your BMR isn't your total caloric need. Your BMR is what your body WOULD need if it where in a coma. Every time you so much as twitch you exceed your bmr. Now lets take two different cases.

Case one 6 foot odd man with 30% body fat. Fat can metabolize about 1600 calories a day all on its own. Long as he doesn't fill the whole day with strenuous crap this person could probably eat 1200 - 1500 cals and still be ok even considering hes a 6 foot odd man. His fat will make up the difference. And his body will get all the calories it needs to be healthy. And this is what a minimum calorie level is about being healthy.

Case two a 5 food odd man with 12% body fat who eats 800 calories a day trying to lose weight. His fat can probably generate about 3-400 a day his bmr is probably in the low 2000's so the total calories available to his body is now well below his bmr. BIG PROBLEM!

Your BMR needs to be fueled or bad things happen but it doesn't have to come from food. If you have a decent amount of body fat you can sustain larger deficits. However it is inadvisable to cut food beyond a certain level hence MFP's 1200 minimum. Some people could safely go below that but they are exceptions. If you have a decent amount of weight to lose then honestly eating 100 below bmr is probably not a big deal. IF you are skinny then yeah your headed up diarrhea drive without a paddle.

Really nice explanation!

rosebette

I'm not saying that I personally should be eating 1800 (since I'm only 120 lbs.), but that hypothetical woman who is my height but 220 lbs. I guess what your saying is that that hypothetical 200 lb. woman could eat 1800 and lose weight. However, would she face the same risk of damage by eating at or below her BMR that I would -- say, if I ate below mine, which is more like 1250? Because this person is seriously overweight and has reserves to draw on, whereas a more average sized person has less reserve.

nicsflyingcircus

I've been eating below my BMR for 4.5 months. I've lost 67.5lbs and feel better than I have in ages. I eat a balanced diet which satiates me. I plan to continue doing so for so long as I continue to lose weight, as I am still over 300lbs.

For the record, I have seen both a physician for comprehensive bloodwork and a registered dietician, who reviewed and approved my intake.

jason_adams

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....

heybales

But say if I weighed 220 instead of 120, that would mean that I shouldn't eat below 1800, yet that is the number of calories to keep a sedentary, overweight person at the same weight he/she currently is. Wouldn't it make sense for that person to eat less than that to lose?

Please re-examine what these things mean - you are confusing yourself.

BMR - what your body would like to burn sleeping deeply 24 hrs daily. As you weigh less, this goes down slowly.

TDEE - what your body burns in total, including BMR, food processing, normal daily activity, and specific exercise if done. As you weigh less, this really goes down faster, because not only is BMR lower, but you are moving less mass around and eating less food.

To lose weight, you merely need to eat below what you burn daily, therefore, eat below TDEE. That's what MFP is trying to do if you use the tool correctly.

BMR is a line in the sand that many people draw - because obviously there is a lower limit to reasonable and healthy and creating an unhealthy body, and you are only going to lose weight and hopefully just fat with a healthy body. Make it unhealthy, it'll fight you for any loss.
Now, if you are lucky enough to be measured out the wazoo because you are in a research study, and they know exactly your BMR, your TDEE, you are healthy except for being overweight, no medical issues, and you keep getting testing the whole time - then indeed you may be given an eating goal below your BMR, and you may be fine for negative effects.

But barring that ability (even under Dr supervision doesn't include those things either), draw a line in the sand, and BMR is an easy one.

Just get it as accurate as you can - using Katch BMR which needs your bodyfat %.

And to the point of being in studies being safer with no negative effects. Not true either actually. They are just accepted negative effects.
http://www.youtube.com/watch?v=2i_cmltmQ6A

Kalikel

I don't even know (or care) the total of my BMR.

RHachicho

Okay lets compare I used a random online calc to get these figures so they may not be exact but they are fine for demonstration purposes.

220lb You BMR 1644.9
-TDEE at Sedentary 1855 calories
-TDEE at Lightly Active 2126 calories
-TDEE at Moderateely Active 2397 calories

120lb You BMR 1209.9
-TDEE at Sedentary 1311 calories
-TDEE at Lightly Active 1502 calories
-TDEE at Moderateely Active 1693 calories

Now for fat metabolism estimations -120lb you 100 - 300 calories
- 220lb you 800 - 1000 calories+

Therefore assuming you are sedentary. (Sitting on yer bum all day) The absolute minimum you could eat safeley at 120lbs is 1000-1100 calories a day. and fact is at that level some times during the day you wont have enough in the tank so bad stuff will happen. So 1200 is more advisable. You are still 100 below your TDEE.

Making that some calculation for the 220lb version of you. You could eat as little as 800 calories safeley. Your fat metabolism would still cover your bmr.

Not only that but as you get to low fat levels you body actively tries to retain it going so far as to destroy muscle tissue as a preference. The generally accepted rule of thumb for weight loss is when the deficit you can sustain safely is tiny. You are pretty much at a healthy weight already. And will have to do decidedly unhealthy things to lose more.

rosebette

But say if I weighed 220 instead of 120, that would mean that I shouldn't eat below 1800, yet that is the number of calories to keep a sedentary, overweight person at the same weight he/she currently is. Wouldn't it make sense for that person to eat less than that to lose?

Please re-examine what these things mean - you are confusing yourself.

BMR - what your body would like to burn sleeping deeply 24 hrs daily. As you weigh less, this goes down slowly.

TDEE - what your body burns in total, including BMR, food processing, normal daily activity, and specific exercise if done. As you weigh less, this really goes down faster, because not only is BMR lower, but you are moving less mass around and eating less food.

To lose weight, you merely need to eat below what you burn daily, therefore, eat below TDEE. That's what MFP is trying to do if you use the tool correctly.

BMR is a line in the sand that many people draw - because obviously there is a lower limit to reasonable and healthy and creating an unhealthy body, and you are only going to lose weight and hopefully just fat with a healthy body. Make it unhealthy, it'll fight you for any loss.
Now, if you are lucky enough to be measured out the wazoo because you are in a research study, and they know exactly your BMR, your TDEE, you are healthy except for being overweight, no medical issues, and you keep getting testing the whole time - then indeed you may be given an eating goal below your BMR, and you may be fine for negative effects.

But barring that ability (even under Dr supervision doesn't include those things either), draw a line in the sand, and BMR is an easy one.

Just get it as accurate as you can - using Katch BMR which needs your bodyfat %.

And to the point of being in studies being safer with no negative effects. Not true either actually. They are just accepted negative effects.
http://www.youtube.com/watch?v=2i_cmltmQ6A

Thanks for this clear break down of all this information.

rosebette

So here's another question based on the HBO video that was posted, and in fact, it's a point my husband and I were having an argument about the other day -- and according to the video, he may be right. According to the video, if an overweight person loses a substantial amount of weight, that person would have to eat much less (about 20%) to maintain than a person who has been at normal weight most of his/her life. My husband has pretty much argued this point, saying that it's nearly impossible for people who have lost large amounts of weight to keep it off and that they have to eat way less than people who are normal weight but the same size. So, if I ate lunch with a woman who was my weight and size, but she had just lost 80 lb. to get there, she would have to eat much less than I to stay normal weight. So, her "TDEE" might be 1300 rather than 1500, for instance.

heybales

So here's another question based on the HBO video that was posted, and in fact, it's a point my husband and I were having an argument about the other day -- and according to the video, he may be right. According to the video, if an overweight person loses a substantial amount of weight, that person would have to eat much less (about 20%) to maintain than a person who has been at normal weight most of his/her life. My husband has pretty much argued this point, saying that it's nearly impossible for people who have lost large amounts of weight to keep it off and that they have to eat way less than people who are normal weight but the same size. So, if I ate lunch with a woman who was my weight and size, but she had just lost 80 lb. to get there, she would have to eat much less than I to stay normal weight. So, her "TDEE" might be 1300 rather than 1500, for instance.

Correct, your total burn is lower than it could have been, so that means you have to eat less to lose or to maintain, then you could have.

Now, subsequent to that study where they claim this is pretty much for life, another very detailed study has shown that even that 20% reduction in daily burn, can be recovered eventually, though it may take awhile.
Also shows that with the right exercise, it doesn't have to happen actually. be aware that in this study, cardio for these folks was like strength training - if they'd kept going other studies show they would have had the same problem eventually.
And in this study, deficit 25% off measured TDEE, rather than the video study where they were over 50% off TDEE.
But do a couple things wrong, and even 25% off TDEE can slow you down 20%.
That could be a real bummer in maintenance, or even reaching goal weight. May not be able to sustain that eating level.

http://www.myfitnesspal.com/blog/heybales/view/reduced-metabolism-tdee-beyond-expected-from-weight-loss-616251

This also speaks to the fact that the non-"study" showing max fat metabolism (it really wasn't a study, it was a theoretical examination of a study already done) doesn't really work out in real life. As these people all had enough fat mass that if that rule worked, even the ones with just diet should not have lowered their daily burn - but they did.
And they all lost LBM.

shadow2soul

So here's another question based on the HBO video that was posted, and in fact, it's a point my husband and I were having an argument about the other day -- and according to the video, he may be right. According to the video, if an overweight person loses a substantial amount of weight, that person would have to eat much less (about 20%) to maintain than a person who has been at normal weight most of his/her life. My husband has pretty much argued this point, saying that it's nearly impossible for people who have lost large amounts of weight to keep it off and that they have to eat way less than people who are normal weight but the same size. So, if I ate lunch with a woman who was my weight and size, but she had just lost 80 lb. to get there, she would have to eat much less than I to stay normal weight. So, her "TDEE" might be 1300 rather than 1500, for instance.

A lot of things come into play when it comes to maintenance calories. Body composition for example, if 2 people of the same height & weight have different muscle to fat ratio's then they will have different maintenance calories.

I have heard that about weight loss as well, but I'm not sure if it's true or not. It would be pretty hard to determine. I mean you would need two people that met the following criteria:
- same age
- same height
- same weight
- same body composition
- same daily activity level
- same amount of exercise
and then one would have to have maintained a healthy weight while the other had lost say 75+ lbs. Even with those conditions met, either person could have had a slightly higher or lower metabolic rate than the average anyway.

heybales

A lot of things come into play when it comes to maintenance calories. Body composition for example, if 2 people of the same height & weight have different muscle to fat ratio's then they will have different maintenance calories.

I have heard that about weight loss as well, but I'm not sure if it's true or not. It would be pretty hard to determine. I mean you would need two people that met the following criteria:
- same age
- same height
- same weight
- same body composition
- same daily activity level
- same amount of exercise
and then one would have to have maintained a healthy weight while the other had lost say 75+ lbs. Even with those conditions met, either person could have had a slightly higher or lower metabolic rate than the average anyway.

Actually no you don't need all that, you'd just need to do the study that is linked above, and what the video shows the why of.
If you read those you'll see the things you are trying to account for already were.

Loss of muscle mass is already factored in. This is a reduction of what your body burns with what is left. Metabolic efficiency. Starvation mode, but without the myths that go along with it (and no, not starving literally which is different). Adaptive Thermogenesis. These are all well known things for many years, even if the why behind it is recent, or how minor a deficit it takes to start seeing it.