Why not eat below BMR?

bpotts44

Most people should completely ignore BMR and focus entirely on TDEE and set a deficit off TDEE either -20% or -500 calories while bottoming out at 1200. Our bodies metabolic activity is extremely complex and many people get distracted by the definition of BMR as the minimum energy our bodies will burn with a supposed minimum intake or all XYZ bad things will happen.

Your body will burn fat to make up for any moderate caloric deficit regardless of the relationship between your actual intake and your BMR. You may lose some LBM through glycogen stores, water, or even muscle but your body is NOT going to go after your muscle first! For optimal results you need to maintain proper exercise and macro nutrient intake, but BMR is not some magical cutoff.

jonnythan

BMR is completely irrelevant when you know a day's TDEE.

myofibril

There's nothing wrong with eating under your BMR or netting under it for that matter.

I think the advice is given as a general guideline to ensure sufficient nutrient and / or energy availability for diets which are going to extend passed the short term (say 6-12 weeks) where the dieter is generally inexperienced.

Obviously prolonged severe caloric restriction can cause some metabolic issues but that is long periods of low calorie dieting (in general and usually combined with a high level of activity.)

Trilby16

My understanding is that your body goes for muscle before fat, and will eventually get used to operating at a reduced efficiency because there isn't enough new food energy. I dont have any links for you, just what I've read over the years from here, books, and websites.

I think it's a choice, do you want to lose fat or muscle? I personally want to lose fat, so I dont want to eat less than 1200 calories or go into starvation mode.

If you look at people anorexic who eat very little or nothing, they lose weight... lots, they lose all their muscle first and then can be 'skinny fat'. eek!

It is hard to believe that the body could be so stupid as to use muscle instead of fat for energy when that's what fat is stored for. Stupid body!

jonnythan

My understanding is that your body goes for muscle before fat, and will eventually get used to operating at a reduced efficiency because there isn't enough new food energy. I dont have any links for you, just what I've read over the years from here, books, and websites.

I think it's a choice, do you want to lose fat or muscle? I personally want to lose fat, so I dont want to eat less than 1200 calories or go into starvation mode.

If you look at people anorexic who eat very little or nothing, they lose weight... lots, they lose all their muscle first and then can be 'skinny fat'. eek!

It is hard to believe that the body could be so stupid as to use muscle instead of fat for energy when that's what fat is stored for. Stupid body!

It's not stupid when you realize that, if it uses muscle preferentially to fat, it can survive starvation for a longer period of time.

Lt_Starbuck

A lot of people like to think of weightloss and getting fit and getting a good body as a 'journey', I like to think of it as a road trip.

Now let's say you want to drive from California to NYC (for funsies). You calculate exactly how much gas it will take you to get from here to there. Let's say, for funsies, that it is 2800 miles, and you know to the drop how much gas that will take.

This is what I would refer to as your BMR. This is how much gas you need just to turn on the engine and drive there. In other words, cardiovascular system, central nervous system, basically just enough fuel (or calories) to drive straight there.

Now - you decide to only bring enough money for 1800 miles and just force your car to work with that. This is considered 'eating below your BMR' and it is very very dangerous to the engine. It will affect your miles per gallon, how often you have to change oil, tough on the gears, crap on everything. Just bad bad bad for the car.

Now - on your way from LA to NYC - you decide to do a few other things - like stop and sightsee here and there. Maybe go off course and find some fun things to do, stop and see friends, go to the bathroom, buy a souvenir or two, stretch your legs, get off the highway, splurge on a hotel, use a phone....

This would be stuff like exercise, cleaning your house, having sex, visiting friends, walking all over the place, playing with kids outside - other things that burn calories ON TOP OF what you burn just 'running' your body's vital systems.

But you still only brought 1800 miles worth of gas money and nothing else...

So now you're stuck in the Midwest. With no gas.

In other words... now you're stuck at this weight.. and you can't do more til you get more fuel.

Give yourself enough gas to get where you're going and do stuff you need to / want to along the way. LIKE EXERCISE.

At first you'll gain a little - and then your body will adjust and it will go away again and take extra pounds with it.

True story.

Lt_Starbuck

My understanding is that your body goes for muscle before fat, and will eventually get used to operating at a reduced efficiency because there isn't enough new food energy. I dont have any links for you, just what I've read over the years from here, books, and websites.

I think it's a choice, do you want to lose fat or muscle? I personally want to lose fat, so I dont want to eat less than 1200 calories or go into starvation mode.

If you look at people anorexic who eat very little or nothing, they lose weight... lots, they lose all their muscle first and then can be 'skinny fat'. eek!

It is hard to believe that the body could be so stupid as to use muscle instead of fat for energy when that's what fat is stored for. Stupid body!

It's not stupid when you realize that, if it uses muscle preferentially to fat, it can survive starvation for a longer period of time.

Quoted for Truth

Capt_Apollo

because

jonnythan

A lot of people like to think of weightloss and getting fit and getting a good body as a 'journey', I like to think of it as a road trip.

Now let's say you want to drive from California to NYC (for funsies). You calculate exactly how much gas it will take you to get from here to there. Let's say, for funsies, that it is 2800 miles, and you know to the drop how much gas that will take.

This is what I would refer to as your BMR. This is how much gas you need just to turn on the engine and drive there. In other words, cardiovascular system, central nervous system, basically just enough fuel (or calories) to drive straight there.

Now - you decide to only bring enough money for 1800 miles and just force your car to work with that. This is considered 'eating below your BMR' and it is very very dangerous to the engine. It will affect your miles per gallon, how often you have to change oil, tough on the gears, crap on everything. Just bad bad bad for the car.

Now - on your way from LA to NYC - you decide to do a few other things - like stop and sightsee here and there. Maybe go off course and find some fun things to do, stop and see friends, go to the bathroom, buy a souvenir or two, stretch your legs, get off the highway, splurge on a hotel, use a phone....

This would be stuff like exercise, cleaning your house, having sex, visiting friends, walking all over the place, playing with kids outside - other things that burn calories ON TOP OF what you burn just 'running' your body's vital systems.

But you still only brought 1800 miles worth of gas money and nothing else...

So now you're stuck in the Midwest. With no gas.

In other words... now you're stuck at this weight.. and you can't do more til you get more fuel.

Give yourself enough gas to get where you're going and do stuff you need to / want to along the way. LIKE EXERCISE.

At first you'll gain a little - and then your body will adjust and it will go away again and take extra pounds with it.

True story.

This is an incredibly terrible analogy. Completely nonsensical.

Here's a better car analogy:

You have a huge tank, one large enough to provide fuel for 40 days, in the back of the bus. You want to use it all. You can't use it all if, at the beginning of every day, you fill the small tank up with exactly enough fuel to make it through that one day. This would be eating TDEE.

So instead you fill the small tank up with enough fuel to make it through the day, minus a couple of gallons. So for the last few miles of the day you're using from the huge tank (your fat stores).

Now ask yourself: if you're driving half the day, does it matter how much fuel you would have used if you just sat around letting the bus idle every day? No. If you want to plan how much fuel to put in the small tank, you look at how much you plan to drive that day. How much you would have used if you didn't drive is irrelevant.

You want to plan so that you can use 5 gallons from the huge tank in the back every day, so you have to look at how much actual fuel you will use that day. The amount of fuel you would have used if you didn't drive makes no difference to anything at all.

JoanB5

BMR is a medical term, not something someone on MFP made up. Your estimated BMR is in fact what they would feed you in the hospital in a coma...which is why the coma comment comes up. Generally speaking, health care professionals, dietitians, and nutritionists do not recommend having a net calorie intake below your BMR unless you have a substantial amount of weight to lose as it can be dangerous...particularly when you're talking about people with 5 or 10 cosmetic Lbs to lose and completely crashing their diets. Having a VLCD prescribed by a Dr. and monitored by a Dr. is a far cry different thing than some random person with 20 Lbs to lose netting 500 calories per day. Really, there's no reason to net below your BMR on any consistent basis without being under the supervision of a health care professional.

Individuals with a substantial amount of weight to lose can get by eating below BMR with few side effects for longer because they have substantial fat stores to burn. Your body is a smart machine...it knows the difference between having 30-40 Lbs of fat reserve to say 200-300 Lbs of fat storage reserve. Your body is going to treat that deficit differently depending on how much you have to lose.

Personally, I think it's really only an issue with people with very drastically low calorie intakes...like having a 1,200 calorie goal and then exercising and netting to 500 or 600 calories. That's just plain unhealthy and completely unsustainable. I'm not so worried about myself occasionally dipping a couple of calories below my BMR or something though...it is an estimate. It's the folks with a BMR of 1,300 or 1,400, but netting 500 that scare the **** out of me. Basically all they are doing is developing an eating disorder (anorexia) at that point.

Well said.

Lt_Starbuck

This is an incredibly terrible analogy. Completely nonsensical.

different things work for different people. different ways of explaining reach different people. Youre incredibly nice though. Totally made me want to read beyond that line.

:drinker:

JoanB5

It's better for me to look at weekly averages rather than get too focused on each day. I'd personally rather go slightly under several days and eat a maintenance cals for a day every week or so than get burned out on routine of hitting it on the dot every day.

One thing you might look at to stay healthy with it is your body measurements, not just your weight loss number. For instance, I see that in "fatty" areas, I've losing a couple inches in the first couple months, but in muscle areas in a couple places, I've gained 1/2" each. To me, this means I'm gaining muscle and losing fat at this point. If that changes, I need to re-evaluate what I'm doing.

I liked the challenge of this article when I was asking the same question last week. Good to keep asking the right questions whether or not there are definitive answers yet. http://fattyfightsback.blogspot.com/2009/03/mtyhbusters-starvation-mode.html

jonnythan

This is an incredibly terrible analogy. Completely nonsensical.

different things work for different people. different ways of explaining reach different people. Youre incredibly nice though. Totally made me want to read beyond that line.

:drinker:

Your analogy is fundamentally flawed in a way that makes it make no sense whatsoever. You're ignoring the fact that the human body has a massive fuel source in body mass that's much larger than the amount of food you can consume.

If you "ran out of gas" when the energy from food ran out, then you wouldn't be able to run a calorie deficit, period. The point of a calorie deficit is so that you empty the "tank" and force your body to start consuming its own "reserve" mass.

FromHereOnOut

I am making a huge mistake by jumping into this analogy nonsense. But neither make sense.

It's more like you have a huge tank full of crude oil and miniature refinery that is powered by gasoline. You put gas in the small tank, but if you only put enough for driving, and not enough to "turn on" the refinery, you'll never convert and burn the crude oil that you've got in your tank.


sigh. I await your picking-apart my analogy.

JoanB5

"The point of a calorie deficit is so that you empty the "tank" and force your body to start consuming its own "reserve" mass."

Exactly what my doctor said. He said that in the short term, dieting every now and then 100 or 150 below the goal MFP is showing should not be an issue for most people wanting to lose weight.

jonnythan

I am making a huge mistake by jumping into this analogy nonsense. But neither make sense.

It's more like you have a huge tank full of crude oil and miniature refinery that is powered by gasoline. You put gas in the small tank, but if you only put enough for driving, and not enough to "turn on" the refinery, you'll never convert and burn the crude oil that you've got in your tank.


sigh. I await your picking-apart my analogy.

What's the real-world analog of "turning on the refinery"? It's like you're saying we need to reserve some calories - BMR - in order to activate fat consumption. Even if that were true, that's not what BMR is at all.

Capt_Apollo

analogies are like apples and pears... you can eat the peel.

FromHereOnOut

Yes, the calories above BMR that prevents your body from adapting itself.

Lt_Starbuck

This is an incredibly terrible analogy. Completely nonsensical.

different things work for different people. different ways of explaining reach different people. Youre incredibly nice though. Totally made me want to read beyond that line.

:drinker:

Your analogy is fundamentally flawed in a way that makes it make no sense whatsoever. You're ignoring the fact that the human body has a massive fuel source in body mass that's much larger than the amount of food you can consume.

If you "ran out of gas" when the energy from food ran out, then you wouldn't be able to run a calorie deficit, period. The point of a calorie deficit is so that you empty the "tank" and force your body to start consuming its own "reserve" mass.

While I think maybe we are both thinking about different things and situations, i think that you would have had me listening to you so much lightning faster and eager to talk to you (like I have always been until this week when you just were so callous and dismissive to me for the too manyeth time) if you had just found the ability to talk to other people around here without starting off with an insult.

Just saying.

jonnythan

This is an incredibly terrible analogy. Completely nonsensical.

different things work for different people. different ways of explaining reach different people. Youre incredibly nice though. Totally made me want to read beyond that line.

:drinker:

Your analogy is fundamentally flawed in a way that makes it make no sense whatsoever. You're ignoring the fact that the human body has a massive fuel source in body mass that's much larger than the amount of food you can consume.

If you "ran out of gas" when the energy from food ran out, then you wouldn't be able to run a calorie deficit, period. The point of a calorie deficit is so that you empty the "tank" and force your body to start consuming its own "reserve" mass.

While I think maybe we are both thinking about different things and situations, i think that you would have had me listening to you so much lightning faster and eager to talk to you (like I have always been until this week when you just were so callous and dismissive to me for the too manyeth time) if you had just found the ability to talk to other people around here without starting off with an insult.

Just saying.

If you take criticism of an idea as a personal attack and insult, I can't help you. I'm not going to try to tiptoe around issues by placating people and telling them that they're good and worthwhile before criticizing a poor idea presented in a post. Sorry. If you don't like that, then just ignore me.