Starvation mode

Well there was a study done that took a group of people and had them consume no calories for days. The results were 72-96 hours on average it took for the metabolism to slow down.

So when on an extreme deficit combined with a high expenditure lifestyle (totally not recommended) it'd probably be advantageous to keep your metabolism running smoothly by having a cheat meal every 3 to 4 days

That's a bit out of context. No calories is VERY different then low calories. Also if the "cheat day" was high calorie enough, it might wipe out the deficit created by the low calorie days. The bottom line is, if you need to lose a lot of weight, you are going to experience some metabolic slowdown along the way. You simply must push through this.

I said cheat meal, not cheat day. The idea of the cheat meal would be to keep the metabolism running smoothly while on a very low calorie diet. It's an idea, or broscience. The no calorie study I mentioned was to give the OP an idea of how hard you would have to diet for starvation to even start happening. No calories is an extreme example and it took 3 to 4 days. That was just one study though. There's of course others. I'd still recommend the 2 cheat meals a week if eating at an extreme deficit 0-500 cal/day or at least eat extra around workout times. I'm a believer in diet experimenting. Live and learn!

1 cheat meal is not going to have a measurable effect on your metabolism like you suspect. Recommending 2 cheat meals per week while dieting on 0-500 calories per day makes no sense because eating that little never ever makes sense. Dieting experimenting like that is just idiotic. There is a difference between experimenting and just doing reckless things.

Most experiments are idiotic. The point of an experiment is to quell one's curiosity by trying an intriguing idea and see what happens. That's how we learn! Most people (especially here in the U.S.) have no clue how efficient the human body is. One of the benefits of even trying to attempt a fasting style diet is the discipline you gain from it. Most people just lack discipline. Taking in zero calories takes a lot of discipline. Do it for a week or two. Unless you have blood sugar issues you'll survive! You don't have to live your life by the textbook.

I don't think most people associate "starvation mode" with literally starving to death, but good on you all who went down that road. I think it's more likely in reference to the problem you get when you undereat and your body decides to hang on to every last calorie out of some biological programming (OMG THERE'S A FAMINE!!).

Weight loss is more than calories in v calories out, sorry. I've eaten 1200 cals for weeks and lost NOTHING, even gained a kg or two, and upped my calories to 1300 or 1400 and started losing again regularly. Lots of people have experienced this. Eating too little and not losing? Up your calories by 100 - 200 and start losing again.

I eat around 1700 to 2100 calories a day these days but less than 20g a day of carbs. I lose weight at the rate of about 1.5kg a week. I'm 40, 5'9" and 104kg. I've lost about 23kg since I started.I would eat close to or slightly over my BMR most days, and I don't exercise. I work in an office. What you eat is equally as important as how many calories. Those who love your internet science, go look it up.

@tuxedord re: metabolism impacts
I do think every body is different, but I'm happy to share my experience, as a sample size of one, and some other observations.

(1) When I consume ~BMR for 4 weeks, my metabolism decreases 20%. I lose weight pretty quick (~1lb/wk) despite the slow metabolism and pretty low BF% (16%). I can continue running 4 mi/day, but I do run faster when fuelled better.

(2) There's a metabolic limit to how much energy fat can render. It's ~30kcal/lb fat/day. Someone carrying 100lb fat can tolerate a big caloric deficit, considering he can get 3000kcal/day from stored fat before eating a bite. This guy will have little metabolic "adverse effect" from severe caloric restriction. Someone with 20 lb fat on their skeleton, by contrast, will see metabolic impacts with a much smaller deficit.

(3) I've had appreciable experience with fasting (for spiritual reasons), and my body reacts very quickly to caloric restriction. Maybe it's because I'm lean to start with or because past experience has conditioned my body to recognize fasting. When I cut calories to <500/day, I feel sleepy within 24 hours. I can think and function fine, but exercise is out of the question and I need 2 hrs more sleep/day.

Weight loss is more than calories in v calories out, sorry. I've eaten 1200 cals for weeks and lost NOTHING, even gained a kg or two, and upped my calories to 1300 or 1400 and started losing again regularly. Lots of people have experienced this. Eating too little and not losing? Up your calories by 100 - 200 and start losing again.

Aren't you special? Why don't you go teach the starving kids in Africa how to gain weight while eating at a deficit.

Weight loss is more than calories in v calories out, sorry. I've eaten 1200 cals for weeks and lost NOTHING, even gained a kg or two, and upped my calories to 1300 or 1400 and started losing again regularly. Lots of people have experienced this. Eating too little and not losing? Up your calories by 100 - 200 and start losing again.

Aren't you special? Why don't you go teach the starving kids in Africa how to gain weight while eating at a deficit.

Did you realize starvation mode and starving are not the same thing?

You are referring to starving, they are referring to starvation mode. Few posts up are a few links with plenty of studies to educate yourself about the mode, not the starving.

And yes, to above post, obviously 1200 was the goal, and was not adhered to constantly very well, probably some binges in there, hence the weight gain.
Exact reason for one of the myths attached to starvation mode, you'll gain fat and weight and burn off muscle. Never mind the fact if deficit was that much you likely burned off muscle anyway, right along with the fat.
Eating more finally just unstressed their body and likely some decent water weight dropped, as well as generally less stress is better for weight loss anyway.

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I don't think most people associate "starvation mode" with literally starving to death, but good on you all who went down that road. I think it's more likely in reference to the problem you get when you undereat and your body decides to hang on to every last calorie out of some biological programming (OMG THERE'S A FAMINE!!).

Weight loss is more than calories in v calories out, sorry. I've eaten 1200 cals for weeks and lost NOTHING, even gained a kg or two, and upped my calories to 1300 or 1400 and started losing again regularly. Lots of people have experienced this. Eating too little and not losing? Up your calories by 100 - 200 and start losing again.

If you were eating at 1200 exactly, and meaning you weighed and measured everything, then you would have still lost weight.
Most likely you were not doing this, and were actually eating at maintenance during that time.

Will your metabolism slow? Yes
Your body by design is meant to preserve life....so if there are less calories coming in, than what is needed, it will do what it can to protect the body and sustain life. But will you stop losing weight? No.

Then you have a hormone (as mentioned by another poster) leptin
Its job / role signals the body to oxidize body fat.....as you get smaller, you have less leptin in your system.....
That is why (depending on where you are with BF% and body weight).....doing a High Carb refeed is recommended.
By doing a high carb refeed, it triggers the release of more leptin in the body.
So do a refeed that is high in carbs, moderate in protein, and little fat.

I eat around 1700 to 2100 calories a day these days but less than 20g a day of carbs. I lose weight at the rate of about 1.5kg a week. I'm 40, 5'9" and 104kg. I've lost about 23kg since I started.I would eat close to or slightly over my BMR most days, and I don't exercise. I work in an office. What you eat is equally as important as how many calories. Those who love your internet science, go look it up.

You don't have to exercise to lose weight.
I will say this though.....be careful, the more weight you lose, without doing exercise.....the more of that weight loss will be from muscle.
Which will slow your metabolism
What you eat is important....but it will still come down to calories....
I mean if you could clarify which foods or calories you are referring too, I would like to hear.

When people up calories and lose weight - its water weight they lose. Dieting is stressful on the body - and as a result, it retains water.

Biggest issues with very low calories are getting enough micro and macro-nutrients, the increased risk of sustainability/adherence as well as its impact on energy levels.

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Okay, okay so starvation mode is a myth. Calories out > than calories in will result in weight loss. Some slowing of the metabolism will happen if the deficit is large enough for long enough.

Maybe OP wants to know how large a deficit can he maintain without adverse effects on his metabolism? I'd like to know that too.

I'd like to know that too, although in addition to effects on metabolism, I'd like to know effects on muscle mass, and on my ability to sustain it, as well as my ability to make fitness gains. I can figure out the latter two, and perhaps observe somewhat the first two (by monitoring yourself for negative effects) but I'd love to know the research.

I don't think there's been a lot that is especially definitive on this topic. There's that study you see cited here a lot that shows that a VLCD has much great effects on metabolism that a 25% deficit and that a 25% deficit without exercise has a more significant effect than a 25% deficit made up of half exercise and half calorie cutting (which seems to have no significant negative effect that won't be cured quickly after one stops dieting), but just that one study seems insufficient and it doesn't address the question I have (and OP seems to have), which is what about a greater deficit where the additional deficit is created by exercise?

As it is, 1-2 lbs per week seems to be the usual advice, unless you are extremely obese and ideally under a doctor's care, so that's what I'm going with, but I'd love more information too.

20% reduction is an overstatement mostly. The reduction in caloric requirements to maintain weight or continuing to lose weight isn't the body defending against fat loss. It's a reduction in the bodies energy demands due to reduced caloric expenditure post fat/lbm reduction.

Please see this video:

http://videocast.nih.gov/summary.asp?live=2993&bhcp=20

And skip to 35:00.

Metabolic reduction is 15%-20%, and is directly related to leptin reduction which is directly related to body fat mass loss.

The effect is a 15%-20% reduction in metabolism, and this effect has been seen in a study of over 100 patients over a 3-4 week period. It has been extrapolated from an NIH database on long-term weight loss to also exist out to 3-4 years of maintained weight loss.

There seems to be a difference between this and the study that heybales cited (which you should look at), which found that the negative effect could be overcome more quickly, especially for those who had a 25% deficit half made up of exercise. Personally, I monitor my TDEE, and (while I admit my way of doing so is imperfect), I've not yet seen a decrease beyond that explained by simply weighing less, which I think can be somewhat explained by the fact that most of the loss occurred while I was extremely overweight, and (to a lesser degree) because I've been working hard to maintain LBM and to do as much of this as possible through exercise.

But let's say that you are right, and the experience of the people in the study or the personal accounts of people like vismal are not representative of what you or I could expect. What difference does it make? I'm fine at the deficit necessary to lose weight, and if at my goal my TDEE isn't about 1900 (which is what's predicted) but 1600 or so, well, that's a bummer, but I'd rather do what is necessary to deal with that than not lose weight at all. I mean, better not to have gotten fat, but that milk is split, right?

Why do you want to starve yourself????????????????

PLEASE EAT! EAT! EAT!!!!!!!!!!!!!!!

Eating 1,700 and burning 1,700 is NOT good!!!

FOOD IS FUEL

THESE FORUMS - AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!! Repeating myself, time & time again

ZZZZZ!!!

Overwrought much?

He clearly said he's using that as an example to simplify his question.

This topic gets debated to death around here. Here's some factual information:

You can starve. If you deprive yourself of enough calories for a long enough period of time, you will die. It has and does happen to people. When people starve to death, they lose TONS of weight. They do not magically stop losing weight because they are starving. They do see some slowdown to their metabolisms but not enough to cease weight loss. They exhaust the great majority of their stored fuel. They look like skeletons before they die.

In order to die you need to be at or near zero intake for a very long time (depending on how much stored energy you have).

So is starvation mode real? It just depends what you mean by starvation mode. If you mean a magical metabolic condition that stops you from losing weight because you are eating low calories, then no, it's a myth. If you are asking can you starve to death by eating nothing or next to nothing for a long long time, then yeah, that can happen.

^ This. Very clear explanation.

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