Eating 500 Calories

Mandi98U
Mandi98U Posts: 115 Member
in Health and Weight Loss
I'm not planning on doing this so don't hate I am just trying to understand things better. If someone was to lose weight eating at a huge unhealthy deficit for example eating only 500 calories a day, then went back up to eating at a maintenance calorie level after losing weight, would they maintain or gain wait since they are eating more than their body is used to and why?

Replies

  • jemhh
    jemhh Posts: 14,261 Member
    The definition of maintenance calories is the number of calories needed to maintain weight. So if you eat at maintenance, you maintain (within a small range, nobody weighs exactly the same every day.) Keep in mind that we are talking about true maintenance, not what a TDEE calculator or MFP says is maintenance.
  • LivingtheLeanDream
    LivingtheLeanDream Posts: 13,342 Member
    It would be madness! eating that low would totally would destroy the metabolism, there's a reason the minimum intake is 1200 cals, that's what our organs need to function properly and there would be a huge amount of muscle lost with the fat...

    But hypothetically to answer, well it depends - their body would be used to eating that much less that their maintenance calories would be well under what the norm would be, it reduces the BMR (basic metabolic rate) over time. Gain happens when we consistently eat over our TDEE / maintenance cals.

  • StealthHealth
    StealthHealth Posts: 2,417 Member
    If a person's maintenance cals were 2500 per day, they ate 500 per day for a period of time to lose weight and then returned to eating at 2500 per day they would gain weight.

    This is because losing weight in this manner means that the weight loss is predominantly lean body mass (LBM) and with reduced LBM a persons metabolic rate is lower*.

    If that same person, rather than returning to 2500 cals, found their true "new" maintenance figure and ate to that they would maintain - that is the "by definition" that @jemhh states.

    It would be interesting to see how much lower that new maintenance was in practice but I'm not going to try I don't recommend anyone else does.

    * there are other factors that would impact upon the "calories out" when returning to normal. NEAT is likely to be suppressed for some time and the new, lower weight would also be a factor.
  • Karen_DisneyFan
    Karen_DisneyFan Posts: 130 Member
    37+ years ago (when I was very young and dumb, lol) I ate 500 calories a day for about 3 months and lost just over 30 pounds. I was able to keep it off for only a short time since I didn't really learn how to eat correctly when not on such a restricted deficit.
    Currently I follow 5:2 - which is 2 days a week at up to 500 calories and then 5 days at "maintenance" or TDEE. My TDEE has gone down from 2100 calories to 1900 over the 2 1/2 years I've been following 5:2. I've lost almost 40 pounds and I still have another 40 or so to go, but this way of life is very sustainable for me and only 2 days a week restricted or "fasting" is not usually too difficult.
    Good luck with whatever you decide to do... I wouldn't recommend 500 calories every day - it's very hard to sustain, but do some research on 5:2/Intermittant Fasting and you might find something that will work for you.
  • Orphanogenesis
    Orphanogenesis Posts: 523 Member
    http://community.myfitnesspal.com/en/discussion/1077746

    http://www.bodyrecomposition.com/fat-loss/why-big-caloric-deficits-and-lots-of-activity-can-hurt-fat-loss.html

    https://www.nationaleatingdisorders.org//
  • size102b
    size102b Posts: 1,370 Member
    edited March 2017
    I've done this and you will lose glycon stores at first then water after if you gradually increase your calories you will still lose weight if you need to once you start eating more you have to gradually increase calories that way you won't get a huge weight gain of water etc
    I've done it
    It doesn't destroy your metabolism or eat your muscle as long as your having extra nutrients

    I've lost weight like this and gained abit back then did cals after and carried on losing 1-2 lbs a week I even built good muscle up.
    I did meal replacements I'd not do them again as its to hard but it never messed me up losing weight again.
  • janejellyroll
    janejellyroll Posts: 25,763 Member
    size102b wrote: »
    I've done this and you will gain glycon stores at first then water after if you gradually increase your calories you will still lose weight if you need to
    I've done it
    It doesn't destroy your metabolism or eat your muscle as long as your having extra nutrients

    I've lost weight like this and gained abit back then dis cals after and carried in losing 1-2 lbs a week I even built good muscle up.
    I did meal replacements I'd not do them again as its to hard but it never messed me up losing weight again.

    Assuming an average sized person, how could eating 500 calories a day *not* result in unnecessary muscle loss?
  • size102b
    size102b Posts: 1,370 Member
    You go into ketosis where your body survives off your fat stores lots doctors recommended these plans
  • janejellyroll
    janejellyroll Posts: 25,763 Member
    size102b wrote: »
    You go into ketosis where your body survives off your fat stores lots doctors recommended these plans

    But there is a limit to how much fat your body can metabolize in a day -- after that, you're using muscle.
  • 3bambi3
    3bambi3 Posts: 1,650 Member
    size102b wrote: »
    You go into ketosis where your body survives off your fat stores lots doctors recommended these plans

    Yeah, no.
  • Nova
    Nova Posts: 10,318 MFP Staff
    Dear Posters,

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