Exercise Calories versus Daily Activity, eating BMR+

dlwyatt82

I know this topic is discussed a lot in other threads, but there seems to be a big hole in some of the arguments about eating at least your BMR which has been bothering me. Some people say to eat (gross) at least your BMR while still maintaining a reasonable deficit below your TDEE. While I haven't seen any scientific research showing what the consequences are of eating less than your BMR for an extended period of time, this first statement seems like good, easy advice without any logical problems.

Then there are people who say you should NET at least your BMR by eating back exercise calories. This is where I have a problem. Please consider:

From a weight loss perspective, there is no distinction between the calories burned as part of your BMR, the calories covered by your daily activity estimate, and the calories burned by activities you track as "exercise" in your diary. Regardless of how you got there, your TDEE is the number that matters; if you eat less than your TDEE, your body has to get those calories from somewhere, and breaks down fat or muscle to do it.

So if you truly wanted to have your NET calories equal your BMR, you would be eating exactly your TDEE for the day, and would be maintaining your current weight rather than losing anything.

susannamarie

So if you truly wanted to have your NET calories equal your BMR, you would be eating exactly your TDEE for the day, and would be maintaining your current weight rather than losing anything.

No, you wouldn't. Because your TDEE would go up as you exercised as well.

Your BMR is not your TDEE.

e.g. Sally Sedentary has a BMR of 1500. Since she's sedentary, she multiplies this by 1.2 to get estimated TDEE of 1800. She decides to net 1500 calories.

She exercises and burns 400 extra calories. So she eats 1900 calories. But her TDEE is now 2200, so she is still at a 300 calorie deficit.

neanderthin

Generally speaking if someone is eating less that their BMR and eating their exercise calories to put them over their BMR then they've been to agressive in their deficit in the first place. Work from TDEE and create a modestdefict, don't complicate it.

dlwyatt82

So if you truly wanted to have your NET calories equal your BMR, you would be eating exactly your TDEE for the day, and would be maintaining your current weight rather than losing anything.

No, you wouldn't. Because your TDEE would go up as you exercised as well.

Your BMR is not your TDEE.

e.g. Sally Sedentary has a BMR of 1500. Since she's sedentary, she multiplies this by 1.2 to get estimated TDEE of 1800. She decides to net 1500 calories.

She exercises and burns 400 extra calories. So she eats 1900 calories. But her TDEE is now 2200, so she is still at a 300 calorie deficit.

You're missing the point of there being no practical difference between exercise calories and those in your activity multiplier, though. Sally didn't truly net her BMR, because she burned those extra 300 calories which were not eaten back. It just looks that way on a diary because it only increases your target for things that are logged as "exercise", but that's a user interface design on a website, and doesn't affect the math.

glassyo

But there's a difference in activity multiplier if you're not counting your exercise in that. Sally wasn't so susannamarie and her math are right.

stormieweather

The activity multiplier of 1.2 assumes sedentary. Those activities are non-exercise things such as sitting at a table, watching tv, taking a shower, cooking dinner. If this person were to then go out and do a cardio class and burn 500 calories, that is on top of that sedentary TDEE. Now, if she wants to ignore her exercise calories, she could up her activity multiplier to 1.3 or 1.4 and then NOT count her exercise calories. This increased multiplier would give her the same calories she would have had at sedentary PLUS her cardio class.

dlwyatt82

Please ignore how MFP organizes calories for the moment, and focus on the actual math of calories burned versus calories eaten. You start by eating exactly your BMR, so that can come off the top of your calories burned. For example:

Bob's BMR is 2000, so he eats exactly 2000 calories as a starting point, so his gross and net are both exactly his BMR.

Bob burns 500 calories doing a cardio workout. His TDEE is now 2500. He eats an extra 500 calories for the day, increasing his gross to 2500, and net is still 2000, his BMR.

Bob burns 400 calories throughout the day at a sedentary activity level. His TDEE is now 2900, but he doesn't eat these calories back. His net is now 1600, 400 less than his BMR.

The point is if you NET your BMR, it means you ate enough calories to cover all of the calories burned above your BMR. That total happens to be your TDEE. Obviously we don't want to do that if we're trying to lose weight, so we subtract a few hundred calories from our TDEE, which also means your true net calories for the day are slightly under your BMR.

Now you can re-introduce MyFitnessPal's interface to the equation. It gives you a "net calories" number which changes when you add exercise to your diary, but ignores the calories added when you estimate your daily activity level.

If, instead of selecting Sedentary and logging 500 calories of exercise separately as in the example above, Bob had just selected a higher activity level which made his "daily activity" estimate 900 calories instead of 400, he could have eaten 2400 calories, which would have shown a 500 calorie deficit for the day, and his "net calories" (the MFP interpretation people keep using) would have also been 2400, higher than his BMR. Hooray for Bob.

However, as the example was shown (with Sedentary selected and 500 calories of cardio logged in the diary), if Bob ate the same 2400 calories, his net for the day would have looked like it was only 1900, because he didn't eat back the entire 500 calories of his workout. Now he's "netting less than his BMR", and is attacked on the forums. Sad, sad, Bob.

But 2400 calories consumed is 2400 calories consumed. It doesn't matter where it gets organized in MFP's numbers. Exercise, daily activity, it all goes equally to your TDEE.

BaconMD

I understand what you are saying, but I don't have any rebuttal.

What I do know is that I am far hungrier when I do a workout, so I have to eat more on those days. I use my exercise calories as my max, and I am consistently aware of my BMR as I drop weight so that I know where I should be eating so as to continue losing weight healthily.

Though I understand your logic, I don't feel the need to drop my caloric intake down to 4-year-old child levels so I can drop all of my weight super fast and post a thread and be praised about what I managed to accomplish by not actually eating enough. Math aside, metabolism can be damaged and I do not feel the need to do that, otherwise I'll put all the weight right back on again when I start eating at proper maintenance levels. This is why I like fat2fitradio.com's method, but due to my inconsistent activity level, I track exercise and eat some or all of it back.

dlwyatt82

I understand what you are saying, but I don't have any rebuttal.

What I do know is that I am far hungrier when I do a workout, so I have to eat more on those days. I use my exercise calories as my max, and I am consistently aware of my BMR as I drop weight so that I know where I should be eating so as to continue losing weight healthily.

Though I understand your logic, I don't feel the need to drop my caloric intake down to 4-year-old child levels so I can drop all of my weight super fast and post a thread and be praised about what I managed to accomplish by not actually eating enough. Math aside, metabolism can be damaged and I do not feel the need to do that, otherwise I'll put all the weight right back on again when I start eating at proper maintenance levels. This is why I like fat2fitradio.com's method, but due to my inconsistent activity level, I track exercise and eat some or all of it back.

Where did I recommend "4-year-old child levels"? In my example, the difference was only 100 calories, and the deficit from the TDEE was only 500, which is exactly what is recommended for healthy, sustainable weight loss. I'm just pointing out that the concept of having your "net calories" be at least your BMR is flawed, because that either means you're eating exactly your TDEE with no deficit (if you're talking about your true net calories), or is based on a meaningless number (if you're using MFP's distinction between "activity calories" and "exercise calories").

neanderthin

Bob's BMR is 2000, so he eats exactly 2000 calories as a starting point, so his gross and net are both exactly his BMR.

Bob burns 500 calories doing a cardio workout. His TDEE is now 2500. He eats an extra 500 calories for the day, increasing his gross to 2500, and net is still 2000, his BMR.

BMR + exercise is not TDEE. TDEE takes into account lifestyle and a thing called non exercise activity themogenesis as well as any metabolic dysfunctions like thyroid, pcos, diabetes etc. My BMR is 1750 and without exercise my TDEE is about 2400 and if I add in my exercise I'm in and around 3000.

dlwyatt82

Bob's BMR is 2000, so he eats exactly 2000 calories as a starting point, so his gross and net are both exactly his BMR.

Bob burns 500 calories doing a cardio workout. His TDEE is now 2500. He eats an extra 500 calories for the day, increasing his gross to 2500, and net is still 2000, his BMR.

BMR + exercise is not TDEE. TDEE takes into account lifestyle and a thing called non exercise activity themogenesis as well as any metabolic dysfunctions like thyroid, pcos, diabetes etc. My BMR is 1750 and without exercise my TDEE is about 2400 and if I add in my exercise I'm in and around 3000.

You're taking a partial quote. I was making a running tally of calories burned, and just referring to it as TDEE the whole way through. You'll see that on the very next line, I added in another 400 for the "non-exercise" calories.

BaconMD

Where did I recommend "4-year-old child levels"? In my example, the difference was only 100 calories, and the deficit from the TDEE was only 500, which is exactly what is recommended for healthy, sustainable weight loss. I'm just pointing out that the concept of having your "net calories" be at least your BMR is flawed, because that either means you're eating exactly your TDEE with no deficit (if you're talking about your true net calories), or is based on a meaningless number (if you're using MFP's distinction between "activity calories" and "exercise calories").

I wasn't talking about you. Don't be so sensitive.

I said you were right, as my deficit comes from my daily activity, not my exercise. Call it whatever you want. But the point is, some will see your logic and believe it's a good thing to have crazy high calorie deficits, which will likely lead to stunted metabolism and difficulty maintaining.

neanderthin

Bob's BMR is 2000, so he eats exactly 2000 calories as a starting point, so his gross and net are both exactly his BMR.

Bob burns 500 calories doing a cardio workout. His TDEE is now 2500. He eats an extra 500 calories for the day, increasing his gross to 2500, and net is still 2000, his BMR.

BMR + exercise is not TDEE. TDEE takes into account lifestyle and a thing called non exercise activity themogenesis as well as any metabolic dysfunctions like thyroid, pcos, diabetes etc. My BMR is 1750 and without exercise my TDEE is about 2400 and if I add in my exercise I'm in and around 3000.

You're taking a partial quote. I was making a running tally of calories burned, and just referring to it as TDEE the whole way through. You'll see that on the very next line, I added in another 400 for the "non-exercise" calories.

Right. I quess I'm missing the point of your post.

dlwyatt82

Where did I recommend "4-year-old child levels"? In my example, the difference was only 100 calories, and the deficit from the TDEE was only 500, which is exactly what is recommended for healthy, sustainable weight loss. I'm just pointing out that the concept of having your "net calories" be at least your BMR is flawed, because that either means you're eating exactly your TDEE with no deficit (if you're talking about your true net calories), or is based on a meaningless number (if you're using MFP's distinction between "activity calories" and "exercise calories").

I wasn't talking about you. Don't be so sensitive.

I said you were right, as my deficit comes from my daily activity, not my exercise. Call it whatever you want. But the point is, some will see your logic and believe it's a good thing to have crazy high calorie deficits, which will likely lead to stunted metabolism and difficulty maintaining.

I also didn't say you were talking about me. It's just that your comments had absolutely nothing to do with the point that I'm trying to argue. I agree with you that having too large of a deficit is not healthy, but that's not what we're discussing in this thread.

dlwyatt82

Bob's BMR is 2000, so he eats exactly 2000 calories as a starting point, so his gross and net are both exactly his BMR.

Bob burns 500 calories doing a cardio workout. His TDEE is now 2500. He eats an extra 500 calories for the day, increasing his gross to 2500, and net is still 2000, his BMR.

BMR + exercise is not TDEE. TDEE takes into account lifestyle and a thing called non exercise activity themogenesis as well as any metabolic dysfunctions like thyroid, pcos, diabetes etc. My BMR is 1750 and without exercise my TDEE is about 2400 and if I add in my exercise I'm in and around 3000.

You're taking a partial quote. I was making a running tally of calories burned, and just referring to it as TDEE the whole way through. You'll see that on the very next line, I added in another 400 for the "non-exercise" calories.

Right. I quess I'm missing the point of your post.

My point is that I keep seeing people on these forums recommend having your net calories be at least your BMR, and it seems like a deeply flawed statement to me. I just tried to lay out my reasons for this impression, and see what people think. So far, most of the replies have just led to me needing to clarify what might be really meant by "net calories", both on paper and on the MFP website. In all cases, it doesn't seem to matter what the relationship between "net calories" and your BMR is.

The scenario most often comes up for people who have selected the Sedentary activity modifier, because difference between your BMR and TDEE may be lower than the 500-ish calorie deficit that you want to achieve for weight loss. In that case, it should be fine to add some exercise and not eat back all the calories. Some people on MFP seem to view that as eating less "net calories" than your BMR, which just doesn't matter. You'd still have eaten (gross) more than your BMR for the day, and simultaneously achieved a 500-1000 calorie deficit.

neanderthin

Bob's BMR is 2000, so he eats exactly 2000 calories as a starting point, so his gross and net are both exactly his BMR.

Bob burns 500 calories doing a cardio workout. His TDEE is now 2500. He eats an extra 500 calories for the day, increasing his gross to 2500, and net is still 2000, his BMR.

BMR + exercise is not TDEE. TDEE takes into account lifestyle and a thing called non exercise activity themogenesis as well as any metabolic dysfunctions like thyroid, pcos, diabetes etc. My BMR is 1750 and without exercise my TDEE is about 2400 and if I add in my exercise I'm in and around 3000.

You're taking a partial quote. I was making a running tally of calories burned, and just referring to it as TDEE the whole way through. You'll see that on the very next line, I added in another 400 for the "non-exercise" calories.

Right. I quess I'm missing the point of your post.

My point is that I keep seeing people on these forums recommend having your net calories be at least your BMR, and it seems like a deeply flawed statement to me. I just tried to lay out my reasons for this impression, and see what people think. So far, most of the replies have just led to me needing to clarify what might be really meant by "net calories", both on paper and on the MFP website. In all cases, it doesn't seem to matter what the relationship between "net calories" and your BMR is.

The scenario most often comes up for people who have selected the Sedentary activity modifier, because difference between your BMR and TDEE may be lower than the 500-ish calorie deficit that you want to achieve for weight loss. In that case, it should be fine to add some exercise and not eat back all the calories. Some people on MFP seem to view that as eating less "net calories" than your BMR, which just doesn't matter. You'd still have eaten (gross) more than your BMR for the day, and simultaneously achieved a 500-1000 calorie deficit.

Personally I'd like to see the term BMR stricken from the dietary landscape. All deficits should be designed from TDEE and not the TDEE found online but the one where people record what they eat while living their lifestyle and create a modest deficit, but that seems too complicated for most people.

dlwyatt82

Personally I'd like to see the term BMR stricken from the dietary landscape. All deficits should be designed from TDEE and not the TDEE found online but the one where people record what they eat while living their lifestyle and create a modest deficit, but that seems too complicated for most people.

I might agree with you there, though the argument of whether to eat (gross) more than your BMR is a separate point entirely. I don't know if there's any convincing science behind the idea that eating less than your BMR causes some sort of negative effect, but assuming it really makes no difference, then you'd be right: BMR would only useful to help you figure out your TDEE, and would have no other impact on the calories you choose to eat.

yarwell

My point is that I keep seeing people on these forums recommend having your net calories be at least your BMR, and it seems like a deeply flawed statement to me.

I follow your argument and I'm with you on that. There's a certain air of Scientology around this "eat your BMR" thing on here, so best get in the wicker man and grit your teeth. Maybe there's a group of anorexics in remission that are deadly opposed to eating less as it got them into difficulties last time.

If my TDEE minus my target deficit comes out above or below my BMR I can see no logical or scientifically supported reason why I should be concerned either way, it's the deficit that counts.

treetop57

Just from reading your first post, I guessed (a) that you're the guy in your profile photo and (b) you're an engineer. Me too!

I think you would be right that eating net BMR would be exactly the maintenance level if you logged every single movement or metabolic function as exercise. You would have to log every blink of the eyes, every calorie spent digesting lunch, every clinch of your butt cheeks. All that kind of stuff is accounted for by the activity factor of 1.25 even for sedentary. When people talk about "netting," they're only subtracting out reasonable estimates of discreet exercise activities above normal daily activities, not all activities above being in a coma.

In any case, it looks like you've been doing great: 40 lbs down since January, around 2.5 lbs a week consistently for three and a half months. Us bigger guys have more wriggle room than smaller women for whom the small margin between 1200, BMR, and TDEE require them to be more exact in estimating energy intake and expenditure.

yarwell

All that kind of stuff is accounted for by the activity factor of 1.25 even for sedentary.

Are the higher levels of activity intended to account for the actual activity, or are they supposed to reflect an increase in metabolic rate as a consequence of being more active, if that makes sense.

In other words if the factor rises to 1.5 for an activity level is that another 0.25 of BMR in the routing metabolic rate while resting, or is it an amount of exercise equal to 0.25 * BMR.

I can see why someone wished to ban it. I would add "net" anything to the list.

dlwyatt82

Just from reading your first post, I guessed (a) that you're the guy in your profile photo and (b) you're an engineer. Me too!

I think you would be right that eating net BMR would be exactly the maintenance level if you logged every single movement or metabolic function as exercise. You're have to log every blink of the eyes, every calorie spent digesting lunch, every clinch of your butt checks. All that kind of stuff is accounted for by the activity factor of 1.25 even for sedentary. When people talk about "netting," they're only subtracting out reasonable estimates of discreet exercise activities above normal daily activities, not all activities above being in a coma.

In any case, it looks like you've been doing great: 40 lbs down since January, around 2.5 lbs a week consistently for three and a half months. Us bigger guys have more wriggle room than smaller women for whom the small margin between 1200, BMR, and TDEE require them to be more exact in estimating energy intake and expenditure.

Yep, the profile photo is my wife and I just after our wedding back in 2008. I work in IT, but I guess "Systems Engineer" still counts.

Honestly, I'm not sure why my weight loss has been so fast. My planned calorie deficit should only be resulting in around about 1-1.5 pounds per week (I even have a "cheat day" once a week where I eat roughly my TDEE). I assume I must be burning more calories in a day than I thought, but I'm certainly not going to complain about losing more weight than planned!

scorpiomfs

what is tdee?

yarwell

Total Daily Energy Expenditure = TDEE

what your body "burns" in calories a day

treetop57

Honestly, I'm not sure why my weight loss has been so fast. My planned calorie deficit should only be resulting in around about 1-1.5 pounds per week (I even have a "cheat day" once a week where I eat roughly my TDEE). I assume I must be burning more calories in a day than I thought, but I'm certainly not going to complain about losing more weight than planned!

When I graph my weight loss and try to correlate with my net calorie intake, I have to use an activity factor of about 1.5 to account for how fast I've been losing weight. Since I have a fairly sedentary lifestyle and log most every non-sedentary activity as exercise, I have no idea why my loss has been faster than predicted. I suspect it's because the formulas for BMR don't work so well for someone who's three or four sigma above the average height. But I like to imagine that the difference is that all the deep thoughts going through my brain all the time suck up a huge number of calories!

treetop57

I was half joking with that last line, but I heard two interesting bits of info the last couple of days that show that it's partially true.

On the Colbert Report Tuesday, the guest (who has written a book on creativity) mentioned that the human brain is a very efficient computer, consuming only 12 Watts. 12 W is about 10.3 kcals/hour or 250 food calories per day.

Then on CSI last night, the medical examiner mentioned that a human brain weighs on average 3 lbs, a little less in women, a little more in men.

So in a 200 lb man with a 2500 calorie total daily energy expenditure, his brain is only 1.5% of his weight, but it's consuming 10% of his total energy.

I have no idea whether this means that thinking more or harder burns more energy!