Starvation mode

Eating too few calories will slow down your metabolism. But a slow metabolism doesn't suddenly make you stop losing weight if you continue eating at a deficit. This myth came from people who crash diet, consuming 500-700 calories a day, drop 5 lbs, then return to normal eating only to find they gained it all back and more.

And yes, it takes consistent, long term (a few weeks) low calorie eating to slow down your metabolism. Likewise, it takes consistent long term normal eating to return it back to it's proper state.

Starvation mode is a myth birthed from a pebble of truth.

The kittens are AWESOME!

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.

Believing in starvation mode is as much a myth as believing that eating Twinkies will make you thin, blonde, and sweet inside.

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.