BMR IS not for obese and morbidly obese people

Personally I think if you are 300-500lbs then you should be trying to lose weight as fast as possible, every moment you are that obese you are putting your life at risk. With that amount of excess fat, your body will use those stores will before any protein from muscle.

Why would a body with plenty of fat (fuel) starve just because you ate under your BMR for a while? Wouldn't that mean our bodies are incapable of using fat as fuel?

Because what BMR actually is. It is not the optional stuff like growing skin/hair, it is more basic stuff.

It is energy supplied to every cell of the body, less to fat, more to muscle and other cells. Mainly to deal with fluid levels.

Since it is energy supplied to the cells, it cannot come from the cells ultimately.

It would be like a rechargeable battery recharging itself - perpetual motion - which we don't have in our body.

So the BMR will lower. If it wants 1600 calories of energy to do it's thing, and it ends up with 1200 because exercise and other things took the rest, it will eventually slow down a certain amount.

And then interestingly, your body slows down other processes so more is left for the BMR - because some functions just must be done no matter what. Net effect, your BMR lowered, and your maintenance lowered, and your calorie burn on everything lowered.

It has no bearing on how much fat you got as supplies.

And bad effect on that slowdown to other energy expenditure - it seems to remain slower than expected for the weight that is eventually reached. So weight loss is still possible, but slower, and bad end effects making weight loss even more difficult to keep off.

http://www.ajcn.org/content/88/4/906.full

But all of that is just a description of a slowed metabolism, not of starvation. The post to which I replied said you would starve if you ate below BMR. A slowed metabolism and starvation are very, very different things.

To eat below this number means you aren't providing your body with the fuel it needs to have basic brain and organ function. That means you're starving.

Wrong. Your body gets the fuel it needs from its fat reserves - that's why they are there. Tens of thousands of calories worth.

If you don't eat for 8 hours your "basic brain and organ function" doesn't stop, does it ? Even after a week without food those functions will be running along at a high percentage of their usual rate.

if u want to lose 1-2/week , it will not works , u have big chance to give up in first 2-3 months and return to your old habits

so lose as possible as u can and then u can control your plan .

^^^ this is totally wrong.
I started on here with a BMI of 40.4 which is 'morbidly obese', my BMR was not over 3000 cals like you said in original post, it was around 1800.
I have stuck to the guidlines provided by MFP and the BMR / TDEE calcs and have lost 42lbs in 6 months without resorting to starving myself and screwing up my metabolism. I didnt give up in the first 2-3 months, if anything a person is more likely to give up when following a super restricted diet as you are suggesting they do so.

If someone is medically advised to eat so little under the supervision of their dr, then thats just fine, but for the average overweight person its not necessary, and a healthy diet and exercise plan with sensible loss goals will work much better long term.

As obese when u lose reasonable amount of pounds then u will think about bmr but until that u should not eat more than 1500 cal .

I disagree.

i'm obese and your post isnt true for me. i'm eating above my BMR and i'm going at a pace to lose all 80 pounds i have within 12 months. i dont eat my exercise calories back.

i also think it's going to depend on what type of activities you are doing as well. i lift heavy weights and do lots of interval training with cardio. there's no way i would be able to get through those workouts and only eat the 1200 calories MFP suggested i eat. I tried it for a few weeks and not only did it take me longer to recover from a lift session but i also didnt see any more weight loss than when i increased by calories to 1800 calories

MFP never suggests that you eat 1200 calories if you are working out like you have been. The suggestion is that you NET 1200 calories, which means you HAVE to eat the exercise calories back.
That is all.

Personally I think if you are 300-500lbs then you should be trying to lose weight as fast as possible, every moment you are that obese you are putting your life at risk. With that amount of excess fat, your body will use those stores will before any protein from muscle.

On principle, that's a good view, but it can be dangerous to try to lose the weight too fast. It's also much easier to sustain the weight loss if it's gradual.

If you can't spell "you", I really don't think you are qualified to give any type of advice!

^^THIS!

While this may work in a very lean person, you don't seem to take account of the energy in fat reserves. Let's say a 50 kg woman at 20% body fat - that's 10 kg of fat or 90,000 calories - why can't some of that be used to fuel body processes ? It's like saying I have to have my laptop and phone plugged in for them to work and ignoring the batteries.

"Where else could it come from ?" - fat reserves. The food you ate last week, month and year that you didn't need which was consequently stored. The energy enters the system at one point in time, and is used in another. Like a rechargeable battery.

Really ? http://www.ajcn.org/content/49/1/93.long put obese women on PSMF at 300 cals/day and their RMR fell 20% but was still over 1200 calories. What's happening here then. Eating a quarter of their BMR, losing weight - 23 kg of fat and 5kg of fat free mass.

I've read many of these, and they all have similar sized BMR reductions and BMRs over 1,000. Show me one that doesn't.

Wow, a depressed RMR by 22% during the diet, and remained depressed at some level for at least 2 months after eating back at new maintenance level - that's a bummer.

If you are saying this indeed vast reserve of energy stores in fat could be used for anything, why is study after study you present showing that metabolism, RMR, or TDEE post study always lower than expected and predicted for their new lower weight?

Every one of these studies presents the findings that some aspect of the metabolism is lower than predicted for the weight or fat-free mass they are now at. One of the studies and this one shows it lowering faster than the loss - so it is slowing down before needing to slow down you might say.
And as this study shows, remains suppressed even beyond the point the diet is over, for at least 2 months, when they stopped checking in.
At that point, they still had plenty of fat, shouldn't the RMR have raised back up to normal level expected for the amount of fat-free mass they now had? Actually, they didn't even match the RMR / lb fat-free mass they had before the diet began.

There is no denying the body can use the fat stores. That's the whole point of creating a safe deficit. You are allowing the body to do it's normal thing of mainly burning fat all day long (except during exercise where larger % carbs), and you just aren't refilling the fat stores to where they were before.

But at some point, you drop too low on creating that deficit, and as all these studies show, the body slows down to adjust, besides also burning muscle. Why does the body do that if still plenty of fat to use?

You seem to be proving the point that despite plenty of fat, the body has to slow down for some reason, and is willing to burn muscle for some reason. Why if there is plenty of fat does it resort to any muscle catabolism at all. Unless you exercise it more than daily activity by having resistance exercises.

I had a couple favorite case studies, but on rereading, they were not obese at all, 40-60 lbs overweight was all, not as in these studies, it may very well be the reason why their RMR's did drop to below 1000. It was also for folks exercising a lot, which these studies had either no exercise like this one, or very realistic schedules of exercise for 3 times a wk or 30 min a day.

So I'll concede that for these obese folks over 45% fat, and perhaps decent weight too, the RMR/BMR is not dropping as low as their diet would indicate, though from the studies it is indeed dropping lower than their fat-free mass would indicate.
Obviously at some point they would have problems when that magical line of enough fat or not enough fat would be crossed, and cause the effects other studies have shown can occur, which are indeed not as obese.

Always wish they had control group eating more sensibly too, to see what the loss could be there.
This group had 17 to 40 kg avg loss over the course of 10 to 23 weeks. That's 1.7 kg per week on avg. 3.7 lbs. While drinking 300 cal a day. Seems super extreme for not that great an increase of weight loss. There are some on MFP eating a whole lot more and losing that much in the Eating more to lose more group
I see why they needed to check back in 4 and 8 weeks after the study. Considering still some RMR suppression, would be interesting to see where they are 1yr later.

Always wish they had control group eating more sensibly too, to see what the loss could be there.
This group had 17 to 40 kg avg loss over the course of 10 to 23 weeks. That's 1.7 kg per week on avg. 3.7 lbs. While drinking 300 cal a day. Seems super extreme for not that great an increase of weight loss. There are some on MFP eating a whole lot more and losing that much in the Eating more to lose more group
I see why they needed to check back in 4 and 8 weeks after the study. Considering still some RMR suppression, would be interesting to see where they are 1yr later.

There is one study that had a control group - sorry I did not keep the URL but the VLCD group (800 calories/day) was 10% depressed but also rebounded with weeks of the end of the VLCD portion of the study.

But I would not live and die by these studies either. As I posted in another thread, I actually had mine tested and turns out it was 10-20% higher than what the fat2fit radio calculators stated it should be. So with that, even following the MFP theories on "never eat below your BMR" I would have been eating as much as 600 calories per day below my real number. But people on here would have been "high-fiving" me.

So look at my ticker - that is all lost since mid January. Yes, it has been anything but linear. But, over the longer times when I compare my real expended rate (tested by a BodyMedia Fit) and add back real consumption of calories over that same time, the difference (divided by 3500) works out to within 2 lbs. So at least for me it still all comes down to calories burned minus calories consumed.

My RMR is 1.9 per minute so if that is depressed after 4 months of eating below the magical BMR, it sure is holding to what the calculations said it should four months back.