I think this is largely a myth. (The 1700 calorie end is vaguely plausible but not the 1300 calorie end). There was a good article posted here a while ago [1] which talked about this.

Now, it isn't necessarily easy to maintain a certain calorie count, in terms of either knowing how much you're eating or actually sticking to it despite hunger pangs. And some foods can help you feel fuller with less, you can have different balance of muscle vs fat at the same weight, etc. In those senses I agree with people who say calories in calories out isn't the whole story. But in the end, thermodynamics always wins.

Quote from the article:

> Starvation Mode is this wacky idea that if you eat too little an amount of calories for an extended period of time your body stops burning fat; in fact, it starts doing the opposite–you start gaining weight ‘even when consuming 800 calories’. Sound familiar?

> So, how much truth is there to this?

> Well, see, Starvation Mode is an odd one. Because, while it’s not entirely correct, it’s not entirely incorrect either.

> The correct part: When you reduce calories, more specifically as you begin to get leaner, there is, in fact, some slowing of metabolic rate.

> The incorrect part: Due to this low-calorie consumption your body decides fuck you and proceeds to enter this phantom zone of otherworldliness where the laws of thermodynamics cease to exist, resulting in no fat loss, or worse, gaining fat on some absurdly low number of calories.

It goes on for quite some time, and it's worth reading, but I'll quote just one more part.

> This British actress was adamant she had a slow metabolism, turned out she was simply misreporting calorie intake.

> When she recorded her food intake via video journal, her intake, according to her, was 1100 calories. When they checked her actual intake (with doubly labelled water) it came to 3000 calories.

> Even when she was keeping a food diary, she misreported by 43%.

[1] https://physiqonomics.com/eating-too-much/ discussed at https://news.ycombinator.com/item?id=31381410

I could do it for a few days but I probably couldn't keep it up for long. I'd throw up probably within a week from gradually basically not being able to keep up. I would still be full from the last one when it came time for the next one, and that would get a bit worse each day.

People are in fact different, and most Americans are like fish that aren't aware of water when it comes to their concept of what is a reasonable amount of food. They are swimming in it all day since birth, and these gross amounts seem normal.

I am thin and energetic. I burn my food. But fairly sedentary and lazy, IE, my job isn't chopping wood all day nor do I ever go to a gym. But I just have nervous energy and am very thin. I'm willing to do active things when there is something to do, I typically go up and down stairs with energy etc. I almost always feel grossly overstuffed after about the 2nd meal if I'm staying with other people and eating on their schedule for more than a day. Normally I just eat one not-large meal late at night and nurse one large (say 14oz) coffee most of the day.

So it's not a slow metabolism, at least as far as most cliche signs appear. When I do eat too much, I don't gain weight much. And yet, I just can not gag down a fraction of what everyone around me eats.

Oh and I'm American too. This isn't coming from an Asian or something when I said Americans. Mostly German & French ancestry. Raised in upper middle class, north east, moved around a out equal parts rural and urban. Basically I was raised in the same environment that I'm saying warped most Americans, and the same quality (good and bad ie processed) and quantity of food was available.

People simply vary and you just can't make many assumptions based on one's own experience.

Wait I just realized something ... unless capitalism has done it's usual thing and hotpockets are much smaller now than the last time I had one. In which case disregard. The more I think about it the more I fear this is entirely likely. :)

If you have that slow of a metabolism then you should either build more lean mass and get more active, which drives up the metabolism, or eat less. One way to eat less without feeling hungry is to eat bulkier food, more fibre, and lower GI foods. Since I started eating pure rye bread I'm much less hungry.

It worked for him