Why not eat below BMR?

I don't think it is that your body begins to "cannibalize" the organs.

I don't think it is that your body begins to "cannibalize" the organs.

OP's word was "catabolize" not "cannibalize".. Two very different things..

Twinketta is right about losing your Lean Body Mass too. You will lose muscle, a lot more than you want to. That is another problem with radical cutting diets.

Wow, I get home and there's a ton of responses! Guess I struck a nerve.

I'm thankful for all the responses, especially for the fact that its drawn some very intelligent folks out of the wood work, many of whom I am hoping to add as MFP friends on this journey.

The reason I had asked was because I have been eating at BMR for 4 weeks now with no movement on the scale; I've been counting calories for 6 weeks and lost about 8 pounds right off the bat in the first 3. I am 65 pounds or so overweight (245lbs, 37 years old, 5'10"). Being stuck, I wanted to make an adjustment but was being torn in both directions - afraid to go lower than BMR because of all the warnings of the dreaded starvation mode and metabolic downregulation, but not quite convinced that my "stall" was do to eating too little and, in fact, feeling overstuffed at trying to eat back all the exercise calories necessary to net my BMR.

So here I am, not much more clear on where to go - as this thread alone shows, there is no real consensus in this forum with respect to BMR. From the posts that make the most sense to me, and many of them seem to be in relative consensus with one another, I gather that the real importance of BMR is its use to derive one's TDEE, a far more useful number from which you can run a controlled deficit, and not as some magical floor. While eating 500 calories a day is obviously harmful, dipping consumption to or slightly below BMR is not the evil that people parrot here.

Thanks a bunch for your help!

If eating below your BMR is perfectly fine, then where do you draw the line? When does a diet cease to be a diet and become an eating disorder. Personally, threads like this seem to simply be attempts at justifying and validating eating disorders. Have fun with y'all's anorexia and 500-800 net calories per day.

I'm out...gotta hit the gym and get home to finish eat my 2150 calories today.

Choosing an arbitrary number for the sake of having a threshold is one thing, but at least admit to what it is. If all you've seen this thread to be is an attempt to justify an eating disorder, then you have some issues with sliding down slippery slopes too easily - not all of us do.

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!

I'm not posting this thread to restart all the flaming and trolling. I want this to shine a bit of objectivity on the subject of very low calorie diets and metabolism. I spent a decent amount of time explaining things in the thread that was deleted, so it was disheartening to see the information deleted. I think we can all agree that among other important goals, this community is about education.

As this thread in question is being discussed on my profile page, someone asked me to re-explain what I discussed in the removed thread. I'm simply going to copy and paste my response here:

Yes, very low calorie diets (VLCD) can reduce RMR and disrupt various components of the endocrine system. But correlation is not causation. Meaning... is it the VLCD or is it the effect of the VLCD that leads to the slowdown? Put differently, VLCD cause high rates of fat loss due to the massive energy deficits. Fat happens to be the home of the master hormone responsible for metabolic regulation - Leptin. Leptin lets out bodies know that it's fed. So if we have less fat, we have less Leptin. If we have less Leptin, we have less of a "fed" signal to the brain. If we have less of a fed signal, the body responds accordingly with the slowdown in RMR (and some other adaptations).

But the logical question you should be asking is, "Won't smaller or normal deficits also cause a loss in fat? And won't that loss in fat lead to the same sort of negative adaptations?" And the answer is yes. It's just that the VLCD will cause these adaptations to happen faster... but you'll also lose fat faster. Follow me?

This isn't an argument for people to start following VLCD as most will fail miserably. Once you factor in the psychology aspects of them, they're just not right for most long term fat loss plans. In addition, the lower your energy intake is, the more careful you have to be about nutritional adequacy. Meaning it becomes very easy to shortchange yourself of particular facets of nutrition, which can ultimately tap into "health."

For example, back in the day when the medical community was busy trying to fix obesity, they used VLCDs and weren't mindful of protein quality or quantity. Protein happens to support muscle mass. Sure, around here we're interested in preserving skeletal muscle, as that's what helps us get "toned," "lean," "athletic looking," "ripped," or whatever the cool buzzword is nowadays. But these experiments on the obese patients led to losses in other types of muscle... namely cardiac muscle, which plays an important role in being alive, obviously.

Point is, the more food you eat, the easier it is to cover all of your nutritional bases. You can still screw things up, but it's just harder.

In the thread that was deleted last night, I spoke of the Minnesota Starvation Experiment ran by Ancel Keys, which took already relatively lean men and locked them down in the lab where they were given 50% of their calorie needs for half of a year. They also had supervised exercise ever day if memory serves me correct. We know that lean people will react faster (in terms of metabolic slowdown) to big energy deficits than fat people will. Which makes sense.... fat bodies don't "think" they're starving as quickly since they have all of this excess energy in storage, right?

But even with the test subjects in this experiment being lean to start, after the 6 month period, they only experienced a slowdown in RMR of 15% or so. I mean total energy expenditure dropped by 40% or so, but the remaining 25% (above the 15%) was due to the loss in weight (tissue costs something to maintain and a bigger body is more expensive to move around). Everyone knows that as weight is lost, calorie needs go down.

The "starvation mode" totaled 15% after half a year of low calorie dieting. And that's the primary point... life requires energy expenditure. And metabolism can be thought of as our total energy expenditure in this case. Even if there is negative adaptation to low calorie dieting, metabolism can only drop so far... there's a minimum threshold that's required to keep your heart beating, to fuel respiration, power the brain, transport nutrients, digest food, etc, etc.

I also posted a few links to more current research.... one paper compared a 25% deficit to a 890 calorie intake. The low calorie intake lost more weight than the 25% group. Yes, they had a metabolic slowdown... but so did the 25% group, which corresponds to what I said above about big and small deficits.

There's a lot more that I could say on the topic. For example, NEAT (non-exercise activity thermogenesis) is turning out to play a substantial role in the reduction in total daily energy expenditure experienced on prolonged diets... big or small deficits. Which only stands to solidify the importance of exercise while dieting. NEAT drops unconsciously... so we counteract that by doing more activity consciously via structured exercise. But we won't dive into that end of things as this is already far too long.

The bottom line is this... VLCDs are not as destructive as people around here are making them out to be. People see VLCD and immediately think of anorexia. Anorexics lose weight past the point of healthy thresholds. They also aren't mindful of nutrition quality, more often than not. Not on low calorie diets are "unhealthy."

There's a time and a place where they may even make sense for some. I've used them. I've used them with some of my clients.

It's just that those times and places don't match beginners who obviously need to learn nutrition fundamentals before they go experimenting with advanced dieting techniques. If they jump right into very strict and limiting diets, there's a good chance they're going to wind up gaining weight, not because of some crazy adaptation that winds up creating stored energy (fat) out of thin air... but because they're not going to stick with it, and when they fall off the wagon, they fall hard and typically eat their faces off.

I'm not out there advocating VLCDs. Not at all... heck, I wrote the Nutrition 101 article, which everyone should have read by now, and nowhere in it did I advocate VLCD. I'm simply trying to maintain the integrity of information while steering people in an optimal direction. It seems like too many people around here are stuck on absolutes. They believe there is 100% right ways of doing things and 100% wrong ways of doing things. There's no in between. In reality, there are very few absolutes in the game of fat loss.

I actually started "medically supervised" weight loss last week with a doctor.
As part of my pre-planning my program, she set me up to have a RMR test -- that's where they determine your resting metabolism rate -- or the energy burned by your body just sitting down quietly. I'll be happy to share the findings:

My weight: 238 pounds
My height: 5'4"
My RMR: 1800 calories.... that's what my body needs to function.
An additional 540 calories was added to the total as "lifestyle & activity" -- getting up to go the copy machine, climbing stairs to the 2nd floor, etc. That's a total RMR of 2340 calories.

The determination is:
1800-2300 calorie daily intake will maintain my current weight.
1440-1800 calorie daily intake is the "weight loss zone."
Anything under 1440 daily calorie intake should be medically supervised.

I'm going back this Saturday to the gym, to have a VO2 test -- that's where they determine your optimal heart rate for weight loss. Most people tend to exercise in the cardio zone -- which is certainly great. But for someone like me who still needs to focus on weight loss - I need to work out at a different heart rate.

I think the key is "medically supervised." I also underwent a complete blood workup and EKG... which will all be repeated in a couple of weeks. As part of my plan I meet with a nutritionist every week and either the doctor or the PA. I am NOT doing the VLC diet, frankly because that kind of scares me... but knowing this other information is pretty helpful in helping me with my day.

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!

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.

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.