'...how long must you be at the increased Caloric rate before the metabolism returns to normal levels. Does periodic increases such as some do with "free days" provide a protective measure against metabolic drop?'
I don't think periodic increases (in calories) as a protective measure against metabolic drop are going to be be easily supported by study results.
But, I'd be interested if you can find that study!
In www.ncbi.nlm.nih.gov/ , the search argument, 'metabolic decrease metabolic increase caloric restriction' does not give the kind of result you are looking for.
I don't know where the 'starvation mode' stuff came from.
Thank you DC!! I appreciate that so much. The term gets thrown around so much, and sometimes I don't feel that people truly understand the concept of it, esp this part:
2. If you consistently eat less than 1200 calories per day (1500 for men), your body will go into starvation mode.
Although there are important reasons why people shouldn’t go below these minimum calorie intake levels (see Question 6 below), there is no single level of calorie intake that determines when people will shift into “starvation mode.” What determines this is the difference between your calorie intake and your needs, which varies for everyone depending on factors like size, age, gender, health factors, and activity level. Also, your individual genetics play a large role in how quickly and how strongly your body responds to extreme calorie deprivation. In most cases, a starvation-level diet is one that persistently provides less than 50% of the energy you would need to maintain your ideal weight at your normal activity level. That could be quite a bit more or less than 1200 calories, depending on individual factors, and it will normally take more than an occasional day of going too low on calories to cause problems.
Fitness Minutes: (14,252)
9,689 3/13/14 12:38 P
This is a great question. We hear about people using this as a reason for them not losing weight, instead of as a reason why they gain weight faster when they resume higher calories.
It slows down metabolism, but not enough to offset the drop in calories. If you cut down to 800 calories a day, and this puts you in " starvation mode ", you will still lose weight, but less, as you both lose total body weight, and as your metabolism slows.
However this idea that this means, if you use 1300 calories for basic body function, that you won't still lose 1 lb. a week, is a problem. The common advice is to restart eating the proper amount of calories, which is good advice. The problem comes when these people believe that they are not losing because they aren't eating enough. If their metabolism is slower, they will gain back faster, and if they believe that they should be losing when they increase calories because they are not in starvation mode, they are severely disappointed. I see this all the time.
The truth is, you will lose weight if you cut calories, but you may also slow down your metabolism, and not see the losses you hope to see. So if you think 1000 daily calorie deficit = 2 lbs. a week, so 2000 = 4 lbs a week, you may find out, it is 2.5, and you are starving. If you follow this long enough, you may slow your BMR from 1500 to 1300, and when you start eating 1500 again, actually gain weight.
I find that starvation mode is most often used by people to explain their inability to lose weight, when to do so, it would need to reduce their BMR's to what they currently consume. Most people have a BMR over 1200, so the probability if you think you are eating 800 calories, and not losing, is that you are not counting calories correctly, and actually eating a lot more.
So really what you need to do, is eat more than your BMR, and never get into starvation mode. I understand that the OP is only discussing it as an intellectual conversation, but it would need to be based on the deficit from each person's individual BMR, and tightly controlled. I think it would be hard to find participants for this study, or to keep them secluded for long enough to guarantee that the results weren't tainted. You couldn't let these people walk past a Cinnabon for example..
You would need to test for caloric deficit to determine the slowing of metabolism, as well as how long it kept declining, while constantly monitoring the health of your patients. You would need patients willing to risk their health, and be imprisoned basically.
I did read a book once that had conscientious objectors to WW2 who agreed to be starved ( simulating German camp prisoners ), under supervision, as an alternative to service, and then when they were emaciated, they were fed back to health to see how to do it.
I would check your library though. The author is Todd Tucker, and the book is the Great Starvation Experiment.. starved so that other would be better fed.
These patients were chosen from work camps here in the U.S. Volunteers, who considered it to be a service to their country, instead of fighting in the war. It took over a year, and I found it to be very interesting, but after reading it, I doubt that the study will ever be repeated.
The previous posters are correct that there are really too many variables involved to give an easy answer to your questions. In general, you'd likely need months of eating below what your body needs in order for your metabolism to start slowing down to compensate. How much it slows down will depend on how much you're eating relative to your individual needs. How long it takes to bounce back will depend on how long you've been eating too little, how significantly you've been eating under what you should be, and how responsive your body is to the changes.
for muscles the use it or lose it period is two weeks. beyond that i agree with renata that there are too many variables for any sort of conclusive studies or data. think of how long the study would have to go on and how many people of how many different body compositions. there just isn't funding for amassing this kind of data, especially when you consider that the already known extreme end is basically bad for you all around. which means it's at least a little ethically grey.
i mean, look at people getting sick. you get the 24 hour flu bug, you're awful for a day or two and most people are fully bounced back by day 7. The more chronic your issue the more of an impact it's going to have on your health and the longer it's going to take to recover from it and the bigger/longer/stronger the issue the less likely it is that you'll be back from it 100%. the closest thing you might be able to find is data on recovering anorexics or cancer survivors, but the before data is likely to be pretty sketchy.
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1,337 3/13/14 7:30 A
I don't know the answers to your questions, but from a scientific viewpoint I'm doubtful that information on the level you are looking for exists. It's too many variables.
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13 3/13/14 5:21 A
So, I know there has been research demonstrating reduced metabolic rate with extremely reduced Caloric intake, and a corresponding rate of loss that is slower than expected based purely on the intake/outtake viewed. Has there been research in exactly how dramatic of a reduction causes this, how long one must be at the reduced rate before the metabolic drop occurs (I assume your body does not respond day by day. We don't tend to be that reactive) - which naturally begs the converse question, how long must you be at the increased Caloric rate before the metabolism returns to normal levels. Does periodic increases such as some do with "free days" provide a protective measure against metabolic drop?
I'm very interested in this research, purely from an intellectual standpoint. It is hard to locate facts and citations rather than supposition.
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