BMR- what does it mean in weight loss?

This thread has some good info on BMR http://www.myfitnesspal.com/topics/show/301237-looking-for-opinions-on-my-plan

The short answer is that you do not want to eat less than your BMR. BMR is what you would burn if you were in a coma all day. Being "lightly active", for example, means you multiply your BMR by 1.3 to get your average calories burned each day (without exercise). Since 1440*1.3 = 1870, for maintenance, that is what you would eat (plus any additional calories you burned from exercise). If you were looking to lose weight, subtract 500 calories a day to lose a pound a week (but eat back any exercise calories)

bump

Your net consumption needs to be below your BMR for you to lose fat. Calories in-calories out should be negative, and calories out is your BMR + your exercise.

^^^^ Incorrect ...

Your BMR is the amount of calories that you would burn if you were in a coma... just to carry out simple tasks like digestion, heart beat, etc. You should never eat below your BMR because that results in wasting ...

Then what you need to do is figure out your average activity level over a 24hr period. For example, for the very sedetary you would multiply your BMR x 20% ...

If you wanna see a great chart ... just go to www.fat2fitradio.com/bmr

For example... my BMR is 1900 ... I eat about 2200-2400 ...

I like this simple way.

Your BMR is the amount of calories that you would burn if you were in a coma... just to carry out simple tasks like digestion, heart beat, etc. You should never eat below your BMR because that results in wasting ...

You made an inductive reasoning error there. You are correct that BMR is the amount of energy you'd need to maintain your current weight in a coma, but that does NOT mean eating below BMR results in 'wasting' or any other bad health side effects in a vacuum. If you were in a coma and were fed below BMR, you would lose weight. If you were fed above BMR in a coma, you would gain weight. But no one reading this thread is in a coma.

Your body doesn't have any mechanism to take the first BMR calories and put them toward digestion, heart beat, etc. and then use any additional calories toward everything else. Your body doesn't even know how many calories you eat; it only knows whether you have too much, too little, or enough of a certain nutrient, and those nutrients when broken down release energy for your body to function. If you have too much, it converts the nutrient to storage (e.g. fat, glycogen) or excretes it. If it has too little, it converts the storage compounds back into the nutrients it lacks and attempts to look for less optimal compounds to use for the same function.

TDEE is a measurement of how much energy you actually need based on your activity level, which is clearly above that of a coma patient. If you eat less than that, you will lose weight. The BMR number is irrelevant at this point. Eating less than TDEE for a person who moves around is the SAME THING as a coma patient being fed under BMR; both people are taking in less than their daily energy needs.

If TDEE - 20% is below BMR (which is probably will be for a sedentary person with an office job or someone only slightly overweight trying to lose the last few pounds), then you will not whither away and die for eating less than your BMR calories, nor will you incur brain damage, heart failure, or any other bad health effects. You are still within a close range of your body's daily energy needs; it will convert stored fat to energy to make up the difference.

So if my BMR is 1234 - as a person with a desk job on a day I don't exercise really, I should eat 20% less than 1234 to lose weight? I'm at the last ~6 pounds I want to lose. But -20% is about 1107 calories, which seems like too little. Am I getting this right?

No, you read me incorrectly.

I said a person with a desk job can have a TDEE - 20% that goes under BMR because of the sedentary lifestyle. You should use a TDEE calculator or MFP's calculator set to "sedentary." If you use a TDEE calculator, subtract 500 calories for every lb/week you want to lose.

No one should be using BMR as a measure to lose weight. It simply doesn't apply to you because you don't spend 24 hours a day sleeping.

Sorry, I misunderstood you. I did a TDEE calculator that said as sedentary my TDEE is 1496. Working out 1-3 times a week its 1714. If I work out 3 times a week do I use the TDEE of 1714 every day? Or just on the days I work out and use the 1496 for days I don't?

Sorry, I misunderstood you. I did a TDEE calculator that said as sedentary my TDEE is 1496. Working out 1-3 times a week its 1714. If I work out 3 times a week do I use the TDEE of 1714 every day? Or just on the days I work out and use the 1496 for days I don't?

Yes, if you don't want to lose any weight. With those calculations, you would take your TDEE and subtract about 10% to 20% from that to continue to lose weight:
1714 - 20% = 1371 calories on the days you work out.
1496 - 20% = 1196....but that's below your BMR, so you would want to only do 10% on those days: 1346 calories on the days you do NOT work out.

Sorry, I misunderstood you. I did a TDEE calculator that said as sedentary my TDEE is 1496. Working out 1-3 times a week its 1714. If I work out 3 times a week do I use the TDEE of 1714 every day? Or just on the days I work out and use the 1496 for days I don't?

Yes, if you don't want to lose any weight. With those calculations, you would take your TDEE and subtract about 10% to 20% from that to continue to lose weight:
1714 - 20% = 1371 calories on the days you work out.
1496 - 20% = 1196....but that's below your BMR, so you would want to only do 10% on those days: 1346 calories on the days you do NOT work out.

Thank you for the breakdown. Why only 10%? If you just can't go below BMR, can I eat, say, 1250 calories on days I don't workout? Or is that just too close to the BMR?

BMR is the amount they would feed you if you were in a coma to support your basic bodily functions. It is not recommended that you eat below this number unless you are very obese. People with a lot of weight to lose can safely eat at this level for a time, but not during their entire weight loss process.

The confusion is...... MFP is not a BMR calculator. It does figure out your BMR based on the Mifflin St. Jeor formula but then it asks you for an activity level for your daily life (not including exercise). Then it subtracts a flat rate of calories to create your calorie deficit, depending on how many pounds per week you tell it you want to lose. If you choose a too aggressive goal, this will often put people below their BMR. Then people who also do not eat exercise calories are often eating dangerously low.

Yeah I am understanding that now. Right now I'm at the point of trying to figure out an accurate BMR for myself so I actually don't eat too low. Sedentary says about 1496 and exercising 3x a week is about 1714. But I'm not sure if that is totally accurate for me because I live in a city and walk a good amount - probably about 30 minutes total for commuting to and from work. Walking to stores during lunch, etc.

When you add in "how much activity" like "sedentary" or "exercise 3x per week" then it is no longer BMR, you are trying to figure out TDEE.

Oops, I did mean TDEE - still getting used to the acronyms

Thank you for the breakdown. Why only 10%? If you just can't go below BMR, can I eat, say, 1250 calories on days I don't workout? Or is that just too close to the BMR?

You *could* do 1250, but your body still won't get the full calories it needs to function once you get out of bed and start moving around. Even on the days when all I do is get up and move to the couch to watch t.v. all day, I still eat at least 1300 calories - even t.v. watching burns *some* calories!

I don't recommend going any lower than 1300 on those days for you....

You have to eat ABOVE your BMR,

No, you don't. I regularly net below BMR and I probably work out more intensily than a lot of people on this board saying that BMR is a magic health problem number.

You *could* do 1250, but your body still won't get the full calories it needs to function once you get out of bed and start moving around.

Your body doesn't need calories to function; it needs proteins, carbohydrates, and fats to function which all release energy when used in metabolism, in addition to vitamins and minerals for enzymes to keep allow your body to keep conducting metabolic processes.

Calories is a convenient measure to find out if you are eating enough on a macro scale and the daily recommended intake is based upon getting the correct ratio of the above compounds, but it isn't what your body actually needs. If I ate 2000 calories of just carbs, I would eventually succumb to muscle atrophy; if I ate 2000 calories of just amino acids then my brain and muscles wouldn't have the glucose they needs to function properly. Your body has mechanisms to compensate for minor shortages of any of the above, but calories in a vacuum is actually a relatively meaningless number when it comes to physical health and the nutrients your body needs.

In fact, you can calculate how much you *actually* need by multiplying your LBM (in kg) by 1.2 to find out how many g of protein you need, and then multiplying your LBM (in kg) by 3-5 to find out how many g of carbs you need, depending on how active you are (athletes would need to do 7-10 g/lbm). Multiply each number by 4 cal/g and that's how many calories you need to survive. So for me (130 lb LBM @ 18% bodyfat):

70.9 g protein * 4 cal/g + 177 g carbs * 4 cal/g + 40 g fat * 9 cal/g = 1353 calories minimum to survive with a regular exercise routine, which is well below my supposed BMR of 1650. If I use my entire bodyweight for carb intake, the number goes to 1504 calories. And that's because BMR is the amount of energy you need to sustain your weight if you slept all day; it is NOT the bare minimum requirements of caloric intake for metabolic processes. If I took out strength training and running 6x a week, I could survive with 1/2 - 2/3 the amount of calories from protein and lower carb intake to 2 g/lbm and be perfectly healthy (I would almost certainly have to supplement this with a multivitamin because I'm not getting all my nutrients from food, but that's besides the point).

Just remember BMR as standing for Bare Minimum Requirements and you're golden... It is the minimum amount needed to healthily sustain someone of your height, weight, age, and gender at a sedentary activity level without risking health.

It doesn't stand for Bare Minimum Requirements. It stands for Basal Metabolic Rate, which is the amount of energy you would consume by doing nothing but sleeping. Your definition is an incorrect inference based off BMR, which is that somehow your body will break down if you go below this magic number, and is the source of widespread misinformation on this site.

You have to eat ABOVE your BMR,

No, you don't. I regularly net below BMR and I probably work out more intensily than a lot of people on this board saying that BMR is a magic health problem number.

You *could* do 1250, but your body still won't get the full calories it needs to function once you get out of bed and start moving around.

Your body doesn't need calories to function; it needs proteins, carbohydrates, and fats to function which all release energy when used in metabolism, in addition to vitamins and minerals for enzymes to keep allow your body to keep conducting metabolic processes.

Calories is a convenient measure to find out if you are eating enough on a macro scale and the daily recommended intake is based upon getting the correct ratio of the above compounds, but it isn't what your body actually needs. If I ate 2000 calories of just carbs, I would eventually succumb to muscle atrophy; if I ate 2000 calories of just amino acids then my brain and muscles wouldn't have the glucose they needs to function properly. Your body has mechanisms to compensate for minor shortages of any of the above, but calories in a vacuum is actually a relatively meaningless number when it comes to physical health and the nutrients your body needs.

In fact, you can calculate how much you *actually* need by multiplying your LBM (in kg) by 1.2 to find out how many g of protein you need, and then multiplying your LBM (in kg) by 3-5 to find out how many g of carbs you need, depending on how active you are (athletes would need to do 7-10 g/lbm). Multiply each number by 4 cal/g and that's how many calories you need to survive. So for me (130 lb LBM @ 18% bodyfat):

70.9 g protein * 4 cal/g + 177 g carbs * 4 cal/g + 40 g fat * 9 cal/g = 1353 calories minimum to survive with a regular exercise routine, which is well below my supposed BMR of 1650. If I use my entire bodyweight for carb intake, the number goes to 1504 calories. And that's because BMR is the amount of energy you need to sustain your weight if you slept all day; it is NOT the bare minimum requirements of caloric intake for metabolic processes. If I took out strength training and running 6x a week, I could survive with 1/2 - 2/3 the amount of calories from protein and lower carb intake to 2 g/lbm and be perfectly healthy (I would almost certainly have to supplement this with a multivitamin because I'm not getting all my nutrients from food, but that's besides the point).

Just remember BMR as standing for Bare Minimum Requirements and you're golden... It is the minimum amount needed to healthily sustain someone of your height, weight, age, and gender at a sedentary activity level without risking health.

It doesn't stand for Bare Minimum Requirements. It stands for Basal Metabolic Rate, which is the amount of energy you would consume by doing nothing but sleeping. Your definition is an incorrect inference based off BMR, which is that somehow your body will break down if you go below this magic number, and is the source of widespread misinformation on this site.

Well, if she weren't confused by the way we tried to simplify it before, I'm pretty sure this post completely threw her off her stride. Yes, I'm sure we understand the differences that you just pointed out. However, for those who are completely confused by it in the first place, sometimes simplifying the definitions a bit is a little easier.

Thank you for pointing out how stupid we all are by attempting to help someone comprehend a difficult subject. And I'm positive she knows exactly what her LBM is and what it stands for so the exact calculations can be made. Very helpful. Thanks.