Calorie requirements for a thin person vs someone who lost weight to become thin.

Ive never been the naturally thin person so have no idea , when im thin its because i have to constantly work at it.

It's not just women. Formerly obese people burn fewer calories than otherwise physically similar people who were never obese. Apparently, the effect lasts for years, perhaps forever.

I believe there is some evidence that more relatively strenuous exercise can offset this, since it seems to be caused by more efficient low level/effort muscle use. I may be misstating that bit, though.

DeguelloTex wrote: »

It's not just women. Formerly obese people burn fewer calories than otherwise physically similar people who were never obese. Apparently, the effect lasts for years, perhaps forever.

I believe there is some evidence that more relatively strenuous exercise can offset this, since it seems to be caused by more efficient low level/effort muscle use. I may be misstating that bit, though.

Exercise may explain the whole thing. People who are "naturally thin" probably move more than people who are obese. When an obese person loses weight, they don't necessarily pick up a habit of moving more, especially if they lost weight by cutting calories rather than through additional exercise. The "naturally thin" person will still burn more calories because they are still exercising while the formerly obese person is still sitting on the couch.

TimothyFish wrote: »

DeguelloTex wrote: »

It's not just women. Formerly obese people burn fewer calories than otherwise physically similar people who were never obese. Apparently, the effect lasts for years, perhaps forever.

I believe there is some evidence that more relatively strenuous exercise can offset this, since it seems to be caused by more efficient low level/effort muscle use. I may be misstating that bit, though.

Exercise may explain the whole thing. People who are "naturally thin" probably move more than people who are obese. When an obese person loses weight, they don't necessarily pick up a habit of moving more, especially if they lost weight by cutting calories rather than through additional exercise. The "naturally thin" person will still burn more calories because they are still exercising while the formerly obese person is still sitting on the couch.

I sincerely hope this is the answer. Because I know I have picked up the habit of building more movement into my day. (Now if only I could start replacing some of this fat with muscle)

It is based on a study that found that weight loss stimulates changes in hormones regulating hunger and metabolism, and that these changes are still seen at least a year later. Your body is constantly bringing you back to a set point, and scientists are unsure when or if your set point can be adjusted downwards.

I'm pretty sure it has to do with metabolic adaptation for people who have dieted for long periods of time. http://www.biolayne.com/tag/metabolic-adaptation/

I guess since you're putting a lot of stress on your body by creating a somewhat large calorie deficit for an extened period of time, it responds by slowing down your metabolism a notch. Permanently ? maybe.
Also since your weight is always moving, up and down or even just down, your body doesn't know its ''natural'', stable weight anymore so it doesn't get adjusted to anything, and will try to make you go back to where you started from because that was its ''settings'' for a majority of your life. (in opposite of a naturally thin person whose original settings already were ''thin'' for long,, the body can take more because it will balance out in orderr to keep the weight off at that ''setting'').
Damn those people I know who grew up in families with a good sense of nutrition, good food and cooked meals etc, they never developped any kind of eating disorder and now they can eat hatever they want on occasion without ever neither thinking of guilt, or putting a single pound on after days of partying :')

HappyCampr1 wrote: »

eclenden01 wrote: »

It is based on a study that found that weight loss stimulates changes in hormones regulating hunger and metabolism, and that these changes are still seen at least a year later. Your body is constantly bringing you back to a set point, and scientists are unsure when or if your set point can be adjusted downwards.

Well, a year isn't very long in the scheme of things. I'll have been in maintenance for a year next month. Not sure I believe in set points though. I think people just have a certain amount of food they like to eat and whatever calories that is is where they naturally end up unless they're specifically paying attention.

I think you're right. A challenge for me has definitely been behavioral triggers--I like to eat at certain times, and doing 16:8 caused me to miss out on some of those times, and I maintained/lost .5 lb a week when I slacked on IF. I can see how I would start to gain if I started in on calorie-dense foods during those triggers.

I would think this would have to do with the amount of lean mass the two people have. All things equal the one with the lower BF% would have higher caloric requirements. Other than that, there could be genetic reasons for the difference, though the amount should not be large, unless there is a medical/hormonal issue going on.

Not sure about the science but anecdotaly, I have seen this to be true. I know for a fact that I have to eat significantly less than other women of a similar height and weight in order to maintain my weight.

Alligator423 wrote: »

Apparently people who have lost weight have a lower NEAT (non-exercise activity thermogenesis) which is made up of little calorie burns like fidgeting. The body subconsciously is always trying to conserve energy after weight loss without you even realizing. I don't think there are/know of studies that follow people long term, so hopefully eventually this effect dissipates. One can hope!

I've read that this has been seen to persist for at least seven years. I don't remember the details, though.

senecarr wrote: »

Outside of differences in lean body mass or activity level, the idea never makes a bit of evolutionary sense.
If your body can just choose to use less calories, why would it ever use more? We evolved an upright gait, with all the back problems that go with and reduced speed, all to save 4 calories per km walking, but we have an energy saver mode we only turn on after we suffer our first feast then famine cycle? What?

It wasn't all to save calories walking. You can see farther upright and you can use tools more efficiently when you aren't using your hands for locomotion.

You have to force your body to build muscle. It's not the default. I don't think it's that outrageous that the default isn't to be hyper-efficient unless circumstances nudge you toward it. It may well not be a zero-cost adaptation, even if it is a good adaptation to deal with less access to food.

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eclenden01 wrote: »

You're underestimating the role of genetics. This study found that obese people burn 60 percent less calories than non obese people in response to exercise after taking into consideration body composition, just as an example. I think I remember seeing that some people burn 3 times as much per pound of resting lean muscle than others.

http://rnd.edpsciences.org/articles/rnd/abs/2005/02/r5205/r5205.html

erickirb wrote: »

I would think this would have to do with the amount of lean mass the two people have. All things equal the one with the lower BF% would have higher caloric requirements. Other than that, there could be genetic reasons for the difference, though the amount should not be large, unless there is a medical/hormonal issue going on.

Yeah, but my genetics were the same when I was having to eat half-gallons of ice cream to keep my weight up during two-a-days and when I was a fat tub of goo. I wasn't always obese.