Is it bad to eat far below your BMR?

jardane1

I have done the calculations and my BMR is around 3740 *i am 452 lb and 6'4 tall*. I want to lose 2 lbs a week so i need to cut out 1000 calories so my normal intake should be 2740. Lately i have been doing a ton of walking, between 3 and 4 miles a day and the calories burned walking are around 1000 calories.

Here are my questions
1. should i be eating back the calories i burn when walking/exercising?
2. Is there a harm in eating far below your daily limit like 500 to 1000 calories below?
3. Is starvation mode a real thing or just something people believe?

bpetrosky

In your situation, eating below your BMR occasionally is not a problem unless you have an underlying health condition such as diabetes.

Ideally, if you follow the NEAT calculation used by MFP (sedentary) and with a 2 lb/wk loss goal, you should be just fine. That should set you at about a 1000 cal deficit. In your case, eating back the calories from exercise should be optional (if you feel hungry, use them, many people use 50% to allow for overestimating the calories from exercise).

Starvation mode is a myth, you won't gain fat by underating. The body doesn't start "starving" after a few hours without food, it takes a severe prolonged situation to trigger the metabolic collapse that is considered starvation. That doesn't mean there aren't harms to undereating though, and good nutrition helps avoid those harms.

jardane1

Thanks, there are times when i am not hungry and i have like 800 calories left in the day and i get worried that if i don't eat them it would be bad. Do you think my 2740 calories sounds about right for someone who is 452lb 6'4 and 29 years of age? I have a desk job and try to walk as much as i can but i would say i am still in the sedentary range.

DemoraFairy

I think you mean your TDEE is 3,740, not your BMR. Your BMR is what you'd burn if you stayed in bed all day, your TDEE is what you burn in a normal day with moving, walking, talking, eating, etc. I get your BMR as being 3,121.

Need2Exerc1se

It's unlikely to be a problem at your size. It's usually only a problem when you are closer to goal and do it for prolonged periods of time.

SonicKrunch

You will be fine however one thing is necessary. Get at least 120-140g of protein everyday(at 2700 that shouldn't be a problem but you need to be eating whole foods) and get good healthy fats around 50-60g a day(salmon, nuts are great sources). The rest can be carbs. You can eat more than these numbers too if you want like up to 200g protein and 80-90g of fat but just stay within your caloric setup.

afatpersonwholikesfood

Put your info into MFP and set it for a loss of 2 lbs per week. How many calories does it give you? Remember that this is a lifelong thing, and you shouldn't do anything to take the weight off that you wouldn't want to do for the rest of your life. Too much deprivation isn't good for your physical or your mental health. 2,700 does sound pretty low to me for a guy your size.

JakeBrownVB

DemoraFairy wrote: »

I think you mean your TDEE is 3,740, not your BMR. Your BMR is what you'd burn if you stayed in bed all day, your TDEE is what you burn in a normal day with moving, walking, talking, eating, etc. I get your BMR as being 3,121.

The guy is 452lbs at 6"4, I can very easily believe his BMR is 3,740.

OP, in your case eating below your BMR will not be a bad thing. Stick to your plan it sounds solid.

FitOldMomma

If you are walking 4 to 5 miles each day, perhaps you should change the activity level to 'lightly active' in the settings. This way you will get a more accurate daily calorie target.

astralpictures

SonicKrunch wrote: »

You will be fine however one thing is necessary. Get at least 120-140g of protein everyday(at 2700 that shouldn't be a problem but you need to be eating whole foods) and get good healthy fats around 50-60g a day(salmon, nuts are great sources). The rest can be carbs. You can eat more than these numbers too if you want like up to 200g protein and 80-90g of fat but just stay within your caloric setup.

Why is it "necessary" to eat that specific amount of protein and "healthy" fat? In terms of weight loss, it doesn't technically matter what your macros are as long as you're eating under maintenance, and you certainly don't need to fit in specific foods like salmon and nuts. And if you're going to talk macros, wouldn't it make sense to provide a percentage ratio instead of a concrete number that may work for you but not others? I certainly don't need 140g of protein a day. If I was concentrating on muscle gains and bulking instead of deficit maybe.

Usually when people worry about eating under BMR it is because their BMR is a lot lower, and the small amount of calories may not be providing adequate nutrients to meet micros. At 2000+ calories, this shouldn't be much of a concern unless you're eating 2500 calories of cupcakes (you'll still lose weight, but will end of vitamin and mineral deficient in the long term).

Lasmartchika

JakeBrownVB wrote: »

DemoraFairy wrote: »

I think you mean your TDEE is 3,740, not your BMR. Your BMR is what you'd burn if you stayed in bed all day, your TDEE is what you burn in a normal day with moving, walking, talking, eating, etc. I get your BMR as being 3,121.

The guy is 452lbs at 6"4, I can very easily believe his BMR is 3,740.

OP, in your case eating below your BMR will not be a bad thing. Stick to your plan it sounds solid.

According to Scooby his BMR is 3,121 and his TDEE at moderately active (since he says he walks a lot) would be 4,838 and TDEE-20% he would have to eat 3,870 calories to lose 1.9 lbs/wk.

OP, where did you get your number? Have you let MFP give you your numbers by choosing 2lbs/wk loss instead?

jardane1

I think i will stick with 2700 calories a day and then do my walking and eat the 1000 calories i burn from that. If i don't feel hungry and i have a lot of calories left over i think i feel better about that.

astralpictures

Be careful with eating back the 1000 calories from walking. You may not be actually burning that much, so a lot of people here say they eat back half of their burn to be safe.

freeoscar

1000 calories from 3-4 miles of walking sounds extremely high. I'm guessing that takes you around 1hr, 1hr 20 minutes, which is more likely a burn of half that or probably even less than that.

jardane1

Sounds wise, but like i said i am always quite a bit under so it should all work out. It sucks how slow weight loss is.

Chrysalid2014

astralpictures wrote: »

SonicKrunch wrote: »

You will be fine however one thing is necessary. Get at least 120-140g of protein everyday(at 2700 that shouldn't be a problem but you need to be eating whole foods) and get good healthy fats around 50-60g a day(salmon, nuts are great sources). The rest can be carbs. You can eat more than these numbers too if you want like up to 200g protein and 80-90g of fat but just stay within your caloric setup.

Why is it "necessary" to eat that specific amount of protein and "healthy" fat? In terms of weight loss, it doesn't technically matter what your macros are as long as you're eating under maintenance, and you certainly don't need to fit in specific foods like salmon and nuts. And if you're going to talk macros, wouldn't it make sense to provide a percentage ratio instead of a concrete number that may work for you but not others? I certainly don't need 140g of protein a day. If I was concentrating on muscle gains and bulking instead of deficit maybe.

Usually when people worry about eating under BMR it is because their BMR is a lot lower, and the small amount of calories may not be providing adequate nutrients to meet micros. At 2000+ calories, this shouldn't be much of a concern unless you're eating 2500 calories of cupcakes (you'll still lose weight, but will end of vitamin and mineral deficient in the long term).

That depends on whether a person wants to lose fat or just "weight", and if they want to remain healthy while doing so. A certain proportion of protein in relation to bodyweight is necessary to preserve LBM in a calorie deficit. And some micronutrients are fat soluble so you need the fats to assimilate them properly.
I actually think Sonic's calculations are too low for OP. @SonicKrunch what formula did you use? The numbers you quoted for protein/fats are the same as my goals (using this guide), and I weigh 210...
http://blog.myfitnesspal.com/a-beginners-guide-to-protein/

senecarr

Agree with Lasmartchika and DemoraFairy. IIFYM's TDEE calculator says to be have a BMR of 3700, he'd need to be 20 years old with a 25% body fat, at 6'4" and 452.

astralpictures

Chrysalid2014 wrote: »

That depends on whether a person wants to lose fat or just "weight", and if they want to remain healthy while doing so. A certain proportion of protein in relation to bodyweight is necessary to preserve LBM in a calorie deficit. And some micronutrients are fat soluble so you need the fats to assimilate them properly.
I actually think Sonic's calculations are too low for OP. @SonicKrunch what formula did you use? The numbers you quoted for protein/fats are the same as my goals (using this guide), and I weigh 210...
http://blog.myfitnesspal.com/a-beginners-guide-to-protein/

So you're claiming that if I'm in a deficit but not eating enough protein and fat, that I will lose weight from other sources more than fat? Funny how I eat more carbs than fat and protein, yet still have been losing mostly fat and still have muscles on my frame. You'd think I'd be nothing but bone and fat now! You have fat storage for a reason, for your body to use as fuel when you're in a calorie deficit. It isn't going to turn to eat mostly muscle instead if you're not eating a massive amount of protein. If you're in deficit, you're going to lose some muscle anyways, but not as drastically as you make it out. I'm also pretty sure that with the typical Western diet, most people are getting plenty of protein and fat without even trying.

SonicKrunch

astralpictures wrote: »

SonicKrunch wrote: »

You will be fine however one thing is necessary. Get at least 120-140g of protein everyday(at 2700 that shouldn't be a problem but you need to be eating whole foods) and get good healthy fats around 50-60g a day(salmon, nuts are great sources). The rest can be carbs. You can eat more than these numbers too if you want like up to 200g protein and 80-90g of fat but just stay within your caloric setup.

Why is it "necessary" to eat that specific amount of protein and "healthy" fat? In terms of weight loss, it doesn't technically matter what your macros are as long as you're eating under maintenance, and you certainly don't need to fit in specific foods like salmon and nuts. And if you're going to talk macros, wouldn't it make sense to provide a percentage ratio instead of a concrete number that may work for you but not others? I certainly don't need 140g of protein a day. If I was concentrating on muscle gains and bulking instead of deficit maybe.

Usually when people worry about eating under BMR it is because their BMR is a lot lower, and the small amount of calories may not be providing adequate nutrients to meet micros. At 2000+ calories, this shouldn't be much of a concern unless you're eating 2500 calories of cupcakes (you'll still lose weight, but will end of vitamin and mineral deficient in the long term).

As Chrysalid said as well. If he wants to lose weight, sure eat 1g of protein and see how that works for him. He'll end up a rail thin 6'4 guy with no energy and no muscle. My 120-140g is based on 0.75g/lb of lean body weight. At 6'4 he should probably weigh around 180-200 pounds. It's actually low as Chrysalid said but there are a ton of people on here that really just don't eat enough protein so even getting 120g is better than some people on here do and will at least maintain most of his muscle mass.

As for you not needing 140g, that depends on your height but from your picture you look to be about 5'8-9 at most(sorry if that's not accurate) so a normal weight would be 140-170 depending on what you want to look like. So you are correct you may not need 140g, though as you said if you were on a bulk you would want that much or a little more. I'm 5'10 and I get about 170 or a little more on my workout days and try to get about 120 on my off days.

astralpictures

I'm about 5'7" - 5'8", and I take in about 50 - 75 grams of protein daily on average. I've had no issues wasting away. Only consuming 1g of protein daily is very unlikely with most people's diets, so is a non-factor.

My point was that while he may reach those protein levels since his calorie allowance is much higher than someone like me, it isn't a necessary to losing weight. There is no way to completely prevent some muscle loss while cutting, as far as I know. But it isn't as dire as losing all muscle either since almost everyone consumes a lot more protein than you'd think (unless you're a vegetarian/vegan and not trying to find other sources than meat).

Kst76

1000 calories sounds about tight for a 450 pound person. 3-4 miles is what, an hour - 90 minute walk Op? I am 174 pound and I burn 300 calories in 60 minutes walking.

DeguelloTex

karintalley wrote: »

1000 calories sounds about tight for a 450 pound person. 3-4 miles is what, an hour - 90 minute walk Op? I am 174 pound and I burn 300 calories in 60 minutes walking.

I'm 230 pounds and so do I. I think one of us is wrong.

rongunz322

I'm 5'11" and currently 264. My BMR is about 2,409. On a cheat day, maybe I'll go over to 2,500 BUT on a regular basis, I do 1,600-2,200 a day and that's not considering my cleaning job at the gym, my weightlifting and walking.

I remember the app telling me I'd be in starvation mode if I don't hit a minimum of 1,200 calories. As for fat loss in the process, lowering my fat content was pretty simple cuz I used to LOVE eating sweets ALL the time but ince eating more veggies, that dropped FAST.

StaciMarie1974

1. When you have 200-300 pounds to lose you don't fit within the 'standard' of 1-2 pounds a week. You can probably aim to lose 1% per week (getting checked out by a doc first would not be a bad thing).

2. Depends on how you feel, and how you prefer to calculate. BMR itself is not a significant # except to estimate total daily burn and such. Again see 1. A 1000-2000 calorie deficit may be safe for you while it isn't even possible for me. (I don't burn 2000 some days.)

3. Myth. Though your body and its systems do work best when you give it proper nutrition, and hydration. Even so there is not a magic # of calories that is ideal.

jardane1 wrote: »

I have done the calculations and my BMR is around 3740 *i am 452 lb and 6'4 tall*. I want to lose 2 lbs a week so i need to cut out 1000 calories so my normal intake should be
2742. Lately i have been doing a ton of walking, between 3 and 4 miles a day and the calories burned walking are around 1000 calories.

Here are my questions
1. should i be eating back the calories i burn when walking/exercising?
2. Is there a harm in eating far below your daily limit like 500 to 1000 calories below?
3. Is starvation mode a real thing or just something people believe?

Kst76

DeguelloTex wrote: »

karintalley wrote: »

1000 calories sounds about tight for a 450 pound person. 3-4 miles is what, an hour - 90 minute walk Op? I am 174 pound and I burn 300 calories in 60 minutes walking.

I'm 230 pounds and so do I. I think one of us is wrong.

Maybe, maybe not. What is your pace?

When I walk I average between 3.7 - 4.1 mph.

SonicKrunch

You can definitely prevent muscle loss while cutting if you are not already within a normal BMI range. Eat enough protein and work your muscles and your body will consume fat stores for energy and use the intaked protein to ensure it doesn't need to eat muscle tissue to survive. Don't eat enough protein and your body will start to consume your muscle tissue along with the fat. This is why a lot of people who lose weight get down to skinny rails at the end of their loss, rather than just ending up with a normal bodyshape.

Being 5'7-8 and only consuming 50-75 grams will mean while you are losing the 50 pounds you still want to go, you will be cannibalizing your muscles on your deficit. Will you lose all your muscle, certainly not but you will end up being quite skinny...which isn't exactly a bad thing either depending on what you are going for aesthetically. Runners/cyclists don't mind being smaller, makes it easier for them to run/cycle. I also have no idea what jardane1's goal is, however since he weighs so much it would be better for him to maintain his muscle mass now and cut his muscle down later if he wants after he's lost a significant amount of fat.

Even taking a low end 0.5g/lb you will end up at 100-125 pounds in maintenance.

As they say muscle requires more calories to sustain themselves, but the actual truth is muscle requires more protein intake which in turn requires more calories, they are not all made the same.

Chrysalid2014

astralpictures wrote: »

I'm about 5'7" - 5'8", and I take in about 50 - 75 grams of protein daily on average. I've had no issues wasting away. Only consuming 1g of protein daily is very unlikely with most people's diets, so is a non-factor.

My point was that while he may reach those protein levels since his calorie allowance is much higher than someone like me, it isn't a necessary to losing weight. There is no way to completely prevent some muscle loss while cutting, as far as I know. But it isn't as dire as losing all muscle either since almost everyone consumes a lot more protein than you'd think (unless you're a vegetarian/vegan and not trying to find other sources than meat).

I don't know why you'd assume that. Many overweight people (myself included) got that way by eating carb-laden and sugary stuff that has very little protein in it relative to the calories, and/or by drinking too much booze.
Now that I've got my macros in order I've actually had to consciously look for ways to increase my protein to the required level. I just am not used to choosing those kinds of foods.

And there are ways to minimize muscle lost while cutting. A very good result is that 15% of the weight you lose will be LBM. A very bad result is 50%. So there's a huge difference in results there.

Sure, it's not necessary to losing "weight", but like Sonic said most people don't want to end up skinny and weak. It takes a lot of time and effort to get that LBM back after you've lost it.

So, this might be something you want to look into further before you lose much more... the subject comes up on an almost daily basis on these forums so there's lots of info available.

DeguelloTex

karintalley wrote: »

DeguelloTex wrote: »

karintalley wrote: »

1000 calories sounds about tight for a 450 pound person. 3-4 miles is what, an hour - 90 minute walk Op? I am 174 pound and I burn 300 calories in 60 minutes walking.

I'm 230 pounds and so do I. I think one of us is wrong.

Maybe, maybe not. What is your pace?

When I walk I average between 3.7 - 4.1 mph.

About 4.5 ... 13:30 miles.

ETA: This week has been 13:19, 13:23, 13:35, and 13:29 per mile for 4.5 miles.

Kst76

Then you are not burning much at all. ..hmmm.
If you are using a HR monitor, as am I, it pretty much proves you can't trust those either .
You are practically jogging and only burn 300 calories.

Kst76

,../

astralpictures

SonicKrunch wrote: »

You can definitely prevent muscle loss while cutting if you are not already within a normal BMI range. Eat enough protein and work your muscles and your body will consume fat stores for energy and use the intaked protein to ensure it doesn't need to eat muscle tissue to survive. Don't eat enough protein and your body will start to consume your muscle tissue along with the fat. This is why a lot of people who lose weight get down to skinny rails at the end of their loss, rather than just ending up with a normal bodyshape.

Being 5'7-8 and only consuming 50-75 grams will mean while you are losing the 50 pounds you still want to go, you will be cannibalizing your muscles on your deficit. Will you lose all your muscle, certainly not but you will end up being quite skinny...which isn't exactly a bad thing either depending on what you are going for aesthetically. Runners/cyclists don't mind being smaller, makes it easier for them to run/cycle. I also have no idea what jardane1's goal is, however since he weighs so much it would be better for him to maintain his muscle mass now and cut his muscle down later if he wants after he's lost a significant amount of fat.

Even taking a low end 0.5g/lb you will end up at 100-125 pounds in maintenance.

As they say muscle requires more calories to sustain themselves, but the actual truth is muscle requires more protein intake which in turn requires more calories, they are not all made the same.

This is my second go around losing the weight. I already almost hit my goal 2 years ago, losing 60 lbs and hitting 160-165 lbs. I actually maintained quite a bit of muscle mass that time around still eating the same amount of protein I am now and lifting about 3 times a week. Did I lose some muscle? Of course, I lost 60 lbs of weight! I put back on some of the weight lost, not all, because I got derailed with quite a bit of stuff all at once. I do agree that a lot of people have trouble becoming "skinny fat" when getting to their goal weight and should pay more attention to macros as the goal becomes closer to being achieved if they want their body composition to be more fit.