Question: Starvation Mode, Why?
Replies
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Thanks guys! This is exactly what I was looking for.
So, I'm reading through the articles, but just to get a live back-and-forth here to deepen my understanding, why are very low calorie diets so demonized?
For example, 900 calories a day for a 180 lb person, a person could lose as much weight as for however long they sustain that eating habit. However, if they were to get to 140 or so and decide that they'd like to maintain that weight, they'd just start eating the "minimum required calories" to maintain, and that would be that. Is that right?
And, if so, what is metabolism and how/why is it affected?
Speaking in general terms:
1) Malnutrition. It's hard to have a well-rounded diet on such low calories and you can end up missing out on vital macro/micronutrients. That can have a lot of negative effects upon your entire body.
2) Body composition. Without adequate protein intake, you increase the risk of losing excessive amounts of muscle along with the fat. This can result in you getting to your goal weight and discovering that you just look like a smaller version of what you were before - skinny, but still soft and flabby. In the vernacular it's referred to as "skinnyfat" - the medical term for it is MONW (Metabolically Obese, Normal Weight). It means that you can still suffer the medical issues associated with obesity even though you're at a "normal" or "healthy" weight because of an excessively high body fat percentage.
3) Workout performance/fatigue. If you're not adequately fueling your workouts, your performance is going to suffer and you're going to feel tired, run down and more prone to injuries because your body can't recover properly without adequate "building materials" (nutrients).
Great info here! That really clarifies the counter argument. However, looking at diets such as Paleo, where the diet is high protein, high veggie, and all around healthy, it seems like this type of lifestyle would be low in calories and high in nutrition. Would a person with this dietary habit still suffer lean muscle loss and malnutrition?
Why I bring up any of this is because I'm committed to a vegetarian-based paleo diet. This diet is focused on protein rich foods, and 90 % veggies. I'm finding it really hard to go above 1000 calories a day with this diet. I'm worried about the long-term implications, as I really like what this diet is doing to my weight, skin, overall wellbeing.
Thanks again for all the awesome insight!
You can check the research by Stuart Phillips. In the past year he published a study in which subjects eating high levels of protein and incurring high deficits did not los any lean mass. However the intake was 2.4 g/kg/day, which is not easy, esp on a vegetarian diet.
It would that high deficits can have fewer negative effects if they result from high volumes of exercise (as opposed to diet only) and people w/higher levels of body fat.
I wouldn't be overly concerned about a low calorie intake if you are just starting out. There will be little short term risk and you have time to refine your diet and add more calories.2 -
When I did my first run with MyFitnessPal back in 2007, Starvation Mode was part of fitness orthodoxy. Here is a discussion from 2008 when it was accepted by all commentors without dissent: http://community.myfitnesspal.com/en/discussion/7611/starvation-mode
Another thread from back then says that MFP will warn you of Starvation Mode if your net calories fall below 1,200 for the day: http://community.myfitnesspal.com/en/discussion/25331/starvation-mode
I took me nine years to put 15 pounds back on, so I am here logging again. Starvation Mode has been reclassified from True to Wacky. That is one reason I like MFP. Advice is based on current science. Fitness woo is not tolerated.
When the evidence changed, the advice kept up with the science.
I agree but...
Yes, undereating can't possibly prevent you from losing fat. But in the right circumstances, it can postpone a drop on the scale by causing you to retain water. Plus it can affect your energy levels and energy expenditure and thereby change your CICO equation.
If you are overweight (obese is outside of this proclamation, more variables to consider), consistent undereating is never the right choice.
It feels to me again as though in our rush to correct the idea that "starvation mode is not a thing", we're ignoring the possibility that a poster is asking because they have been eating too few calories.
I like the concept that "he who eats the most and still loses is the winner".
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Karen,
I'm leaning on that side myself. However, what lead you to believe this? Do you have any articles?
Thanks for the input!
History is full of natural experiments. People have starved for many reasons like famine, war, etc. None of them became obese as a result of not eating enough.8 -
Starvation is a very real process and can lead to death.
Your body does not stop losing weight at a certain point that would cause you to go into "starvation mode", where you would quit losing weight. Everyone has seen photos of starving people that look like skeletons with skin covering them.
If your body is not getting enough nourishment (food & water) over time ( and it could be a matter of 6-8 weeks sometimes less, sometimes more ) vital organs will begin to shut down, leading to death, eventually.1 -
Thanks guys! This is exactly what I was looking for.
So, I'm reading through the articles, but just to get a live back-and-forth here to deepen my understanding, why are very low calorie diets so demonized?
For example, 900 calories a day for a 180 lb person, a person could lose as much weight as for however long they sustain that eating habit. However, if they were to get to 140 or so and decide that they'd like to maintain that weight, they'd just start eating the "minimum required calories" to maintain, and that would be that. Is that right?
And, if so, what is metabolism and how/why is it affected?
Speaking in general terms:
1) Malnutrition. It's hard to have a well-rounded diet on such low calories and you can end up missing out on vital macro/micronutrients. That can have a lot of negative effects upon your entire body.
2) Body composition. Without adequate protein intake, you increase the risk of losing excessive amounts of muscle along with the fat. This can result in you getting to your goal weight and discovering that you just look like a smaller version of what you were before - skinny, but still soft and flabby. In the vernacular it's referred to as "skinnyfat" - the medical term for it is MONW (Metabolically Obese, Normal Weight). It means that you can still suffer the medical issues associated with obesity even though you're at a "normal" or "healthy" weight because of an excessively high body fat percentage.
3) Workout performance/fatigue. If you're not adequately fueling your workouts, your performance is going to suffer and you're going to feel tired, run down and more prone to injuries because your body can't recover properly without adequate "building materials" (nutrients).
Great info here! That really clarifies the counter argument. However, looking at diets such as Paleo, where the diet is high protein, high veggie, and all around healthy, it seems like this type of lifestyle would be low in calories and high in nutrition. Would a person with this dietary habit still suffer lean muscle loss and malnutrition?
Why I bring up any of this is because I'm committed to a vegetarian-based paleo diet. This diet is focused on protein rich foods, and 90 % veggies. I'm finding it really hard to go above 1000 calories a day with this diet. I'm worried about the long-term implications, as I really like what this diet is doing to my weight, skin, overall wellbeing.
Thanks again for all the awesome insight!
Are you getting adequate protein and fat on your 1000 calories? I don't see how you're getting enough vegetarian protein, especially considering that, strictly speaking, paleo diets exclude legumes, soy and dairy. If you're relying on eggs, nuts and veggies to get your protein (unless you're going by the RDA, which is ridiculously low), that should be blowing that 1000 calorie target out of the water.
Honestly, adding an extra 200 calories isn't hard; it's an extra tablespoon of olive oil throughout the day and a handful of berries, or another baked sweet potato, or a very small handful of any kind of nut. There's absolutely no reason you should find it hard to add something that small.4 -
Hi Everyone,
So, I'm scientifically minded, and I like to understand the chemistry and other metabolic processes that are going on in weight loss. Don't get me wrong, I'm not actually a scientist or otherwise scientifically-educated, so I'm really coming from a zero-knowledge standpoint here.
That being said, I was wondering if anyone knows why our metabolism rates suffer so much if we "enter starvation mode" by eating less than our daily required calories every day? I'm stumped on this because I don't understand why we'd go into starvation mode when we have fat to burn. It seems counter-evolutionary.
How could our bodies magically (seemingly) decide to lessen the amount of calories needed to function due to "starvation mode" based on short-term eating changes? How would eating fewer calories than the daily requirement make the base metabolism suffer longterm?
Anyone have any ideas or articles they could link?
Starvation mode as it is often applied isn't a thing. Adaptive thermogenesis is a thing...meaning your metabolism will dial down to some extent in a calorie deficit in that your body will make adjustments to become more efficient...this is actually an evolutionary protection against starvation and limited food supply. Basically, steep deficits will cause your body to shut down "non-essential" functions to become more efficient...things like growing hair...nails turn brittle...loss of menstrual cycle, etc. Involuntary movements also decrease which will ultimate have a negative impact on the CO side of the equation.
Also, steep deficits can really jack around with hormones which can have a negative impact on resting metabolism. Steep deficits also stress the body which raises cortisol levels which can impede fat loss.2 -
cwolfman13 wrote: »Hi Everyone,
So, I'm scientifically minded, and I like to understand the chemistry and other metabolic processes that are going on in weight loss. Don't get me wrong, I'm not actually a scientist or otherwise scientifically-educated, so I'm really coming from a zero-knowledge standpoint here.
That being said, I was wondering if anyone knows why our metabolism rates suffer so much if we "enter starvation mode" by eating less than our daily required calories every day? I'm stumped on this because I don't understand why we'd go into starvation mode when we have fat to burn. It seems counter-evolutionary.
How could our bodies magically (seemingly) decide to lessen the amount of calories needed to function due to "starvation mode" based on short-term eating changes? How would eating fewer calories than the daily requirement make the base metabolism suffer longterm?
Anyone have any ideas or articles they could link?
Starvation mode as it is often applied isn't a thing. Adaptive thermogenesis is a thing...meaning your metabolism will dial down to some extent in a calorie deficit in that your body will make adjustments to become more efficient...this is actually an evolutionary protection against starvation and limited food supply. Basically, steep deficits will cause your body to shut down "non-essential" functions to become more efficient...things like growing hair...nails turn brittle...loss of menstrual cycle, etc. Involuntary movements also decrease which will ultimate have a negative impact on the CO side of the equation.
Also, steep deficits can really jack around with hormones which can have a negative impact on resting metabolism. Steep deficits also stress the body which raises cortisol levels which can impede fat loss.
And some of those adaptations endure well after the deficit condition passes.
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I'd be curious to see what happens to people who have been anorexic for years. Do they pile on the weight in record time when they start eating normally again? Do they have to eat less than another person at the same weight, but who has never suffered from anorexia? Have they done irreparable damage, and their system will never work efficiently again, or does it return to normal eventually?3
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Try toasting your cashews or buying roasted ones - I dislike the flavour of raw cashews but love them cooked. Most nuts are improved by cooking.1
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Christine_72 wrote: »I'd be curious to see what happens to people who have been anorexic for years. Do they pile on the weight in record time when they start eating normally again? Do they have to eat less than another person at the same weight, but who has never suffered from anorexia? Have they done irreparable damage, and their system will never work efficiently again, or does it return to normal eventually?
I gained 70 lbs in, like, 4 months. However, I was not eating normally. My body finally broke and I started binging.2 -
Christine_72 wrote: »I'd be curious to see what happens to people who have been anorexic for years. Do they pile on the weight in record time when they start eating normally again? Do they have to eat less than another person at the same weight, but who has never suffered from anorexia? Have they done irreparable damage, and their system will never work efficiently again, or does it return to normal eventually?
Honestly, I think *true* anorexics struggle to gain. I doubt that any one that has struggled with it ever "piles on weight in record time". It's a mental/control issue - trying to overcome the perception of being *not perfect". It's very very hard to get past that perception. I've never been anorexic, but I have known a couple.6 -
lemurcat12 wrote: »Thanks guys! This is exactly what I was looking for.
So, I'm reading through the articles, but just to get a live back-and-forth here to deepen my understanding, why are very low calorie diets so demonized?
For example, 900 calories a day for a 180 lb person, a person could lose as much weight as for however long they sustain that eating habit. However, if they were to get to 140 or so and decide that they'd like to maintain that weight, they'd just start eating the "minimum required calories" to maintain, and that would be that. Is that right?
And, if so, what is metabolism and how/why is it affected?
Speaking in general terms:
1) Malnutrition. It's hard to have a well-rounded diet on such low calories and you can end up missing out on vital macro/micronutrients. That can have a lot of negative effects upon your entire body.
2) Body composition. Without adequate protein intake, you increase the risk of losing excessive amounts of muscle along with the fat. This can result in you getting to your goal weight and discovering that you just look like a smaller version of what you were before - skinny, but still soft and flabby. In the vernacular it's referred to as "skinnyfat" - the medical term for it is MONW (Metabolically Obese, Normal Weight). It means that you can still suffer the medical issues associated with obesity even though you're at a "normal" or "healthy" weight because of an excessively high body fat percentage.
3) Workout performance/fatigue. If you're not adequately fueling your workouts, your performance is going to suffer and you're going to feel tired, run down and more prone to injuries because your body can't recover properly without adequate "building materials" (nutrients).
Great info here! That really clarifies the counter argument. However, looking at diets such as Paleo, where the diet is high protein, high veggie, and all around healthy, it seems like this type of lifestyle would be low in calories and high in nutrition. Would a person with this dietary habit still suffer lean muscle loss and malnutrition?
Why I bring up any of this is because I'm committed to a vegetarian-based paleo diet. This diet is focused on protein rich foods, and 90 % veggies. I'm finding it really hard to go above 1000 calories a day with this diet. I'm worried about the long-term implications, as I really like what this diet is doing to my weight, skin, overall wellbeing.
Thanks again for all the awesome insight!
How much protein are you actually getting on your diet? I ask, because I have some experience with paleo (not doing it any more) and it prohibits two of the easiest vegetarian sources of protein: legumes and dairy. I think getting adequate protein on vegetarian paleo would be tough even without eating only 1000 calories. And some of the sources of protein (eggs, nuts and seeds) would be higher cal due to the fat content.
Anyway, I basically agree with AnvilHead's comments, and my understanding is that too steep a deficit can be a problem for muscle loss and greater metabolic adaptation than necessary, even with a healthy diet, and same for workout performance, of course. I also think a diet can't be considered truly healthy if it's hard to eat adequate calories on it--after all, how would you consider eating in that manner at maintenance if it makes eating adequate calories too much of a challenge?
I average at around 40-50 g of protein a day, with fortified meat substitutes, spinach, legumes, etc. Everything I eat has some protein in it, because I seek it out. I don't feel deprived at all during the day, which is why by the end of the day, I end up being so low in calorie totals. I'm working to end my day at at least 1200 calories, though, after hearing everyone's input here.
My thoughts behind paleo are basically that I'm a mindless eater, and I do not naturally gravitate towards healthy choices. If I might my standard base diet a heathy one, then I wont have to worry about eating processed, chemical filled crap or being addicted to sugar, or any of the other hazards modern day diets cause. I'd also love to drop some pounds. I have a condition called PCOS, so it's ridiculously difficult for me to lose weight, even with low calorie intake, as well (if anyone has any input on that, please let me know!)
Thanks for the interest and information!! I really appreciate it.
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lemurcat12 wrote: »Thanks guys! This is exactly what I was looking for.
So, I'm reading through the articles, but just to get a live back-and-forth here to deepen my understanding, why are very low calorie diets so demonized?
For example, 900 calories a day for a 180 lb person, a person could lose as much weight as for however long they sustain that eating habit. However, if they were to get to 140 or so and decide that they'd like to maintain that weight, they'd just start eating the "minimum required calories" to maintain, and that would be that. Is that right?
And, if so, what is metabolism and how/why is it affected?
Speaking in general terms:
1) Malnutrition. It's hard to have a well-rounded diet on such low calories and you can end up missing out on vital macro/micronutrients. That can have a lot of negative effects upon your entire body.
2) Body composition. Without adequate protein intake, you increase the risk of losing excessive amounts of muscle along with the fat. This can result in you getting to your goal weight and discovering that you just look like a smaller version of what you were before - skinny, but still soft and flabby. In the vernacular it's referred to as "skinnyfat" - the medical term for it is MONW (Metabolically Obese, Normal Weight). It means that you can still suffer the medical issues associated with obesity even though you're at a "normal" or "healthy" weight because of an excessively high body fat percentage.
3) Workout performance/fatigue. If you're not adequately fueling your workouts, your performance is going to suffer and you're going to feel tired, run down and more prone to injuries because your body can't recover properly without adequate "building materials" (nutrients).
Great info here! That really clarifies the counter argument. However, looking at diets such as Paleo, where the diet is high protein, high veggie, and all around healthy, it seems like this type of lifestyle would be low in calories and high in nutrition. Would a person with this dietary habit still suffer lean muscle loss and malnutrition?
Why I bring up any of this is because I'm committed to a vegetarian-based paleo diet. This diet is focused on protein rich foods, and 90 % veggies. I'm finding it really hard to go above 1000 calories a day with this diet. I'm worried about the long-term implications, as I really like what this diet is doing to my weight, skin, overall wellbeing.
Thanks again for all the awesome insight!
How much protein are you actually getting on your diet? I ask, because I have some experience with paleo (not doing it any more) and it prohibits two of the easiest vegetarian sources of protein: legumes and dairy. I think getting adequate protein on vegetarian paleo would be tough even without eating only 1000 calories. And some of the sources of protein (eggs, nuts and seeds) would be higher cal due to the fat content.
Anyway, I basically agree with AnvilHead's comments, and my understanding is that too steep a deficit can be a problem for muscle loss and greater metabolic adaptation than necessary, even with a healthy diet, and same for workout performance, of course. I also think a diet can't be considered truly healthy if it's hard to eat adequate calories on it--after all, how would you consider eating in that manner at maintenance if it makes eating adequate calories too much of a challenge?
I average at around 40-50 g of protein a day, with fortified meat substitutes, spinach, legumes, etc. Everything I eat has some protein in it, because I seek it out. I don't feel deprived at all during the day, which is why by the end of the day, I end up being so low in calorie totals. I'm working to end my day at at least 1200 calories, though, after hearing everyone's input here.
My thoughts behind paleo are basically that I'm a mindless eater, and I do not naturally gravitate towards healthy choices. If I might my standard base diet a heathy one, then I wont have to worry about eating processed, chemical filled crap or being addicted to sugar, or any of the other hazards modern day diets cause. I'd also love to drop some pounds. I have a condition called PCOS, so it's ridiculously difficult for me to lose weight, even with low calorie intake, as well (if anyone has any input on that, please let me know!)
Thanks for the interest and information!! I really appreciate it.
many women here have PCOS and lose weight and they dont have to resort to low calories. a lot of them do low carb/keto. its still about CICO.I have a metabolic disorder and lose weight,its slower but it still comes off from being in a deficit(CICO). check the low carb forums and Im sure many can help you out2 -
Karen,
I'm leaning on that side myself. However, what lead you to believe this? Do you have any articles?
Thanks for the input!
You're asking for studies to prove a negative ("starvation mode does not exist").
That's not how science works.
If someone is proposing that something exists, especially something so counter to all observed phenomena as a biological mechanism that amounts to creating energy out of nothing (by having your body not only function on far fewer calories than it would otherwise need, without tapping stored energy, but even having it "hold on" to the calories you are taking in and storing them as additional calories, which is how most people describe this "starvation mode" mechanism), then it's up to them to provide studies that shows this actually occurs.
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My take is there is no such thing as starvation mode, but
When someone is on a VLCD or even just lower calorie without strength training they are losing muscle mass as well as fat and as muscle burns more Calories than fat they will end up needing fewer Calories to just exist than someone of the same weight who has either not needed to lose weight to get there or has lost at a slower rate and strength trained.0 -
lynn_glenmont wrote: »Karen,
I'm leaning on that side myself. However, what lead you to believe this? Do you have any articles?
Thanks for the input!
You're asking for studies to prove a negative ("starvation mode does not exist").
That's not how science works.
If someone is proposing that something exists, especially something so counter to all observed phenomena as a biological mechanism that amounts to creating energy out of nothing (by having your body not only function on far fewer calories than it would otherwise need, without tapping stored energy, but even having it "hold on" to the calories you are taking in and storing them as additional calories, which is how most people describe this "starvation mode" mechanism), then it's up to them to provide studies that shows this actually occurs.
That's not exactly true. We frequently use science to prove negatives. Also, just because there aren't studies that show something occurs doesn't mean it doesn't occur. It is possible to prove, for example, that the moon isn't inhabited. At the same time, it possible that there is there is an object orbiting the sun that no studies have been done on.0 -
Christine_72 wrote: »I'd be curious to see what happens to people who have been anorexic for years. Do they pile on the weight in record time when they start eating normally again? Do they have to eat less than another person at the same weight, but who has never suffered from anorexia? Have they done irreparable damage, and their system will never work efficiently again, or does it return to normal eventually?
For me no. When I was in inpatient and day hospitalization treatment the goal was to gain 1-2 kg a week until you reach BMI 20 starting at 1,500 calories and increasing it by 300 until at least 2,100. I got up to 3,600 a day and never once gained more than 0.5 kg a week and I was on exercise restriction. My metabolism must have went insane only to gain 1 lbs a week on 3,600! My starting weight was BMI 16 and I didn't ever reach 20 by the time I was discharged after 5 months.1 -
cwolfman13 wrote: »Hi Everyone,
So, I'm scientifically minded, and I like to understand the chemistry and other metabolic processes that are going on in weight loss. Don't get me wrong, I'm not actually a scientist or otherwise scientifically-educated, so I'm really coming from a zero-knowledge standpoint here.
That being said, I was wondering if anyone knows why our metabolism rates suffer so much if we "enter starvation mode" by eating less than our daily required calories every day? I'm stumped on this because I don't understand why we'd go into starvation mode when we have fat to burn. It seems counter-evolutionary.
How could our bodies magically (seemingly) decide to lessen the amount of calories needed to function due to "starvation mode" based on short-term eating changes? How would eating fewer calories than the daily requirement make the base metabolism suffer longterm?
Anyone have any ideas or articles they could link?
Starvation mode as it is often applied isn't a thing. Adaptive thermogenesis is a thing...meaning your metabolism will dial down to some extent in a calorie deficit in that your body will make adjustments to become more efficient...this is actually an evolutionary protection against starvation and limited food supply. Basically, steep deficits will cause your body to shut down "non-essential" functions to become more efficient...things like growing hair...nails turn brittle...loss of menstrual cycle, etc. Involuntary movements also decrease which will ultimate have a negative impact on the CO side of the equation.
Also, steep deficits can really jack around with hormones which can have a negative impact on resting metabolism. Steep deficits also stress the body which raises cortisol levels which can impede fat loss.
I would argue that the bodily responses to a steep deficit that you've outlined justifies the use of the term "starvation mode" in that situation.
I think it's a dangerous practice to jump into a thread without knowing specifics about the OP and say something like, "starvation mode is a myth, you need to eat less not more". (This last statement is not directed at you cwolfman, just in general).
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Found this years ago and in my experience as a trainer and reading forums like this, this applies to most people when they start.
11 reasons you are not losing weight, brief on starvation mode
Another good article with links about starvation mode and such0 -
Everybody has some good comments here. I think you will generally find that starvation mode is considered a myth. The bottom line is that in order to lose weight you have to be in a calorie deficit, period. When you operate at a calorie deficit your body is burning fat stores (and unfortunately muscle if your not careful). That is the goal if you want to lose weight. Whether you eat 1,200 calories per day or 2,500; you have to burn more calories than you eat in order to be in that deficit. I don't believe there is any difference between a person that eats 1,200 and burns 1,500; and a person that eats 2,500 and burns 3,000. The effects on the body are exactly the same.
The real question is whether you are nutritionally sound and giving your body the appropriate amount of nutrients for your health. Some believe that you can't properly do this with lower than 1,200 calories per day. I think that is debatable depending on the vitamin supplements you take and the quality of the food that you are eating. In my opinion starvation is depriving the body of proper nutrients which can be done no matter how many calories you are taking in. You could be eating that 2,500 calories per day and still be "starving" if you aren't taking in the proper balance of healthy foods and nutrients.
So for me personally, I am not hung up on some calorie minimums. I am more interested in the balance of what I am eating and how my calories are burned.0 -
"In the wild," body fat is precious and is difficult to obtain. Once you've got it, your body is going to do everything it can to defend it. That's why if your body senses that it's entering a time of famine, hormonal changes happen to protect your fat stores. You can call it "starvation mode" or not, but whether you believe "starvation mode" exists, there are metabolic changes that work to conserve your energy stores.
It's not going to somehow prevent you from ultimately losing weight (and then dying) if you're truly starving, but the body definitely does respond to extended deprivation by attempting to stave off starvation in a number of ways.2 -
Use google scholar to search for NEAT. Read a lot of stuff. You'll figure out that as people consume 500 calories below their NEAT for an extended time, they lose weight and their NEAT falls.
If the person started their weight loss project with a calorie goal of 1800 that was 500 below their NEAT of 2300, then stayed really good on that target every day for a few months, they would lose weight. Yeah!. But, if they kept their calorie target at 1800 while their NEAT fell to 1800 due to both weight loss and the metabolic damage of excessive calorie deprivation, they'd stop losing weight. This is NOT "starvation mode". This is what happens when you're doing it wrong.
The person should re-calculate their nutrition needs for continued weight loss at intervals of 5 or 10 lb lost throughout their weight-loss project.0 -
"In the wild," body fat is precious and is difficult to obtain. Once you've got it, your body is going to do everything it can to defend it. That's why if your body senses that it's entering a time of famine, hormonal changes happen to protect your fat stores. You can call it "starvation mode" or not, but whether you believe "starvation mode" exists, there are metabolic changes that work to conserve your energy stores.
It's not going to somehow prevent you from ultimately losing weight (and then dying) if you're truly starving, but the body definitely does respond to extended deprivation by attempting to stave off starvation in a number of ways.
Savithny, let's run with that thought for a moment. "In the wild," which do you think the body would want to protect more, the fat that is so difficult to come by, or the muscles and other organs that the body uses to keep it alive?1 -
goldthistime wrote: »cwolfman13 wrote: »Hi Everyone,
So, I'm scientifically minded, and I like to understand the chemistry and other metabolic processes that are going on in weight loss. Don't get me wrong, I'm not actually a scientist or otherwise scientifically-educated, so I'm really coming from a zero-knowledge standpoint here.
That being said, I was wondering if anyone knows why our metabolism rates suffer so much if we "enter starvation mode" by eating less than our daily required calories every day? I'm stumped on this because I don't understand why we'd go into starvation mode when we have fat to burn. It seems counter-evolutionary.
How could our bodies magically (seemingly) decide to lessen the amount of calories needed to function due to "starvation mode" based on short-term eating changes? How would eating fewer calories than the daily requirement make the base metabolism suffer longterm?
Anyone have any ideas or articles they could link?
Starvation mode as it is often applied isn't a thing. Adaptive thermogenesis is a thing...meaning your metabolism will dial down to some extent in a calorie deficit in that your body will make adjustments to become more efficient...this is actually an evolutionary protection against starvation and limited food supply. Basically, steep deficits will cause your body to shut down "non-essential" functions to become more efficient...things like growing hair...nails turn brittle...loss of menstrual cycle, etc. Involuntary movements also decrease which will ultimate have a negative impact on the CO side of the equation.
Also, steep deficits can really jack around with hormones which can have a negative impact on resting metabolism. Steep deficits also stress the body which raises cortisol levels which can impede fat loss.
I would argue that the bodily responses to a steep deficit that you've outlined justifies the use of the term "starvation mode" in that situation.
I think it's a dangerous practice to jump into a thread without knowing specifics about the OP and say something like, "starvation mode is a myth, you need to eat less not more". (This last statement is not directed at you cwolfman, just in general).
Yes, when you get to the point that you're shutting down bodily functions, you are starving your body...and steep deficits can be very dangerous.1 -
TimothyFish wrote: »"In the wild," body fat is precious and is difficult to obtain. Once you've got it, your body is going to do everything it can to defend it. That's why if your body senses that it's entering a time of famine, hormonal changes happen to protect your fat stores. You can call it "starvation mode" or not, but whether you believe "starvation mode" exists, there are metabolic changes that work to conserve your energy stores.
It's not going to somehow prevent you from ultimately losing weight (and then dying) if you're truly starving, but the body definitely does respond to extended deprivation by attempting to stave off starvation in a number of ways.
Savithny, let's run with that thought for a moment. "In the wild," which do you think the body would want to protect more, the fat that is so difficult to come by, or the muscles and other organs that the body uses to keep it alive?
I read in the intro to a weightloss study about an obese person who starved to death and remained technically obese at the time of death. So this person, who still had a good supply of fat available, cannibalized enough organ tissue to cause organ failure. That case changed my thinking about vlcds.1 -
goldthistime wrote: »I read in the intro to a weightloss study about an obese person who starved to death and remained technically obese at the time of death. So this person, who still had a good supply of fat available, cannibalized enough organ tissue to cause organ failure. That case changed my thinking about vlcds.
I do not know the study that you are referring to, but my feeling on this happening would be that the person was severely restricting protein intake (the body cannot convert either fat or carbs to amino acids) and that the resulting cannibalism of the protein from muscles and organs caused the death w/o eliminating a great deal of the adipose tissue from the body.0 -
goldthistime wrote: »I read in the intro to a weightloss study about an obese person who starved to death and remained technically obese at the time of death. So this person, who still had a good supply of fat available, cannibalized enough organ tissue to cause organ failure. That case changed my thinking about vlcds.
I do not know the study that you are referring to, but my feeling on this happening would be that the person was severely restricting protein intake (the body cannot convert either fat or carbs to amino acids) and that the resulting cannibalism of the protein from muscles and organs caused the death w/o eliminating a great deal of the adipose tissue from the body.
I agree, that seems the most likely scenario. This case was just mentioned in passing, no details were given.
0 -
TimothyFish wrote: »"In the wild," body fat is precious and is difficult to obtain. Once you've got it, your body is going to do everything it can to defend it. That's why if your body senses that it's entering a time of famine, hormonal changes happen to protect your fat stores. You can call it "starvation mode" or not, but whether you believe "starvation mode" exists, there are metabolic changes that work to conserve your energy stores.
It's not going to somehow prevent you from ultimately losing weight (and then dying) if you're truly starving, but the body definitely does respond to extended deprivation by attempting to stave off starvation in a number of ways.
Savithny, let's run with that thought for a moment. "In the wild," which do you think the body would want to protect more, the fat that is so difficult to come by, or the muscles and other organs that the body uses to keep it alive?
YOu're painting it as a zero-sum game. I was answering the specific question in the OP.
The OP's question was "why would you not just burn fat rather than slow metabolism?" And the answer is: "Because it is better for the organism to slow metabolism and not burn fat if you don't have to."
If you're running low on gas and you don't know when the next gas station is, do you drive as fast as possible with the windows down and the AC on? Or do you slow down, try to drive more efficiently and make the gas you have last as long as possible. Same thing.
"In the wild," of course the body wants to burn the fat first. But it doesn't want to burn the fat OR lose the muscle. So first it cuts down on energy expenditure in a number of ways, both hormonal and by cutting back on movement.
The fact that *we* think of extra fat as bad stuff that should be gotten rid of is largely cultural. It's also the result of knowing that over a long life in a resource-rich environment, extra fat is unhealthy. That's not really the "in the wild" that we are adapted to living in, though.4 -
goldthistime wrote: »TimothyFish wrote: »"In the wild," body fat is precious and is difficult to obtain. Once you've got it, your body is going to do everything it can to defend it. That's why if your body senses that it's entering a time of famine, hormonal changes happen to protect your fat stores. You can call it "starvation mode" or not, but whether you believe "starvation mode" exists, there are metabolic changes that work to conserve your energy stores.
It's not going to somehow prevent you from ultimately losing weight (and then dying) if you're truly starving, but the body definitely does respond to extended deprivation by attempting to stave off starvation in a number of ways.
Savithny, let's run with that thought for a moment. "In the wild," which do you think the body would want to protect more, the fat that is so difficult to come by, or the muscles and other organs that the body uses to keep it alive?
I read in the intro to a weightloss study about an obese person who starved to death and remained technically obese at the time of death. So this person, who still had a good supply of fat available, cannibalized enough organ tissue to cause organ failure. That case changed my thinking about vlcds.
Goldthistime, there is a more simple possibility that would explain this other than that the body has a desire to hang on to fat. Because we have the same number of fat cells when we are obese and when we are thin, the ability of fat cells to process fat and release it as energy is limited, but the number of calories obese people use to move their fat around is tremendous. Even getting out of their recliner and going the bathroom is equivalent to a weight lifting set for a thin person. If they don't eat enough, their normal activities could outpace the release of fat and they would starve to death. It isn't that the body wants to hang onto the fat, it just can't keep up with the demand.0 -
TimothyFish wrote: »lynn_glenmont wrote: »Karen,
I'm leaning on that side myself. However, what lead you to believe this? Do you have any articles?
Thanks for the input!
You're asking for studies to prove a negative ("starvation mode does not exist").
That's not how science works.
If someone is proposing that something exists, especially something so counter to all observed phenomena as a biological mechanism that amounts to creating energy out of nothing (by having your body not only function on far fewer calories than it would otherwise need, without tapping stored energy, but even having it "hold on" to the calories you are taking in and storing them as additional calories, which is how most people describe this "starvation mode" mechanism), then it's up to them to provide studies that shows this actually occurs.
That's not exactly true. We frequently use science to prove negatives. Also, just because there aren't studies that show something occurs doesn't mean it doesn't occur. It is possible to prove, for example, that the moon isn't inhabited. At the same time, it possible that there is there is an object orbiting the sun that no studies have been done on.
No, it really isn't. All you can say is you haven't found any life or any sign of life in the parts of the moon you have observed at the times that you have observed them. There could be life there in some part you haven't observed, or life you don't recognize as life, or life that is intentionally hiding from you and moving away as you approach any particular place. You can't prove any of those possibilities are untrue.3
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