3500 calories = 1lb of fat - is this fact or myth?

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I'm trying to calculate my personal tdee because with the calories set by mfp I've been gaining at a rate of around 1 lb a week and all the online tdee calculators give different results.
So (sorry,this is boring !) I tried to work it out by calculating my average calories per week (over 8 weeks)and then subtracting 3500.
But have also seen a couple of articles saying the 3500 rule is a myth and that there are no hard and fast rules!

Replies

  • Gallowmere1984
    Gallowmere1984 Posts: 6,626 Member
    edited November 2016
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    That is the amount of energy contained, but that does NOT mean 3500 kcals of deficit will result in 1 lbs. of fat loss. The body has a lot of ways of storing energy; fat just so happens to be the most space efficient.

    ETA: this is why a caloric surplus is generally required for any amount of appreciable muscle accumulation. Muscle tissue's storage is roughly 700 kcal/pound. Unfortunately, the body just doesn't like to put that 700 kcal there as much as it likes to put the 3500 into the adipose tissue. If only it were so easy to forcefeed muscle. We'd all be Stan Efferding within a month of 8,000 kcal/day. ;)
  • comptonelizabeth
    comptonelizabeth Posts: 1,701 Member
    edited November 2016
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    So can I assume that my tdee is roughly calories consumed minus 3500 (per week?) As I'm thinking that a gain of 1lb per week is too fast- I mean I'm happy to be a bit fatter but there will come a point where I'm not! (And yes I'm lifting but as a 61 year old woman with a chronic health condition I know I can't expect to gain much in the way of muscle !)
  • trigden1991
    trigden1991 Posts: 4,658 Member
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    Don't think your maths is quite right;

    Average Daily Calories - (average pounds per week gained * 3500/7) = TDEE
  • PAV8888
    PAV8888 Posts: 13,633 Member
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    There is some elasticity in your metabolism and you may also be gaining for other reasons too (water retention due to exercise for example); but, in general, you can assume you're eating about 3500 above TDEE. if you want to get very technical about it you could determine a ratio of fat to lean mass that you may be thinking/hoping you're accomplishing (say 1:1, which would be pretty good) and then calculating the average.

    Now while Gallowmere above gives an in range number for fat catabolised (I use 800 instead of 700), the synthesis of lean mass seems to be a very inefficient process. And I've seen figures that I've averaged to around 4200 Cal for 1lb of lean mass anabolised.

    And of course you should probably ignore scale weight and look at trending weight applications or web sites to judge changes in weight.
  • comptonelizabeth
    comptonelizabeth Posts: 1,701 Member
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    Don't think your maths is quite right;

    Average Daily Calories - (average pounds per week gained * 3500/7) = TDEE

    Thank you - yes I know, sorry it was clumsily put. I calculated it weekly then divided by 7.

  • comptonelizabeth
    comptonelizabeth Posts: 1,701 Member
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    To be honest I think I'll just ditch calculations and jus assume I need to cut my daily amount to slow down the rate of gain!
  • Mycophilia
    Mycophilia Posts: 1,225 Member
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    There's also articles that explain in more detail what the 3500 calorie rule is and how you should/shouldn't apply it. As with most things, there are some caveats to take into consideration.
  • trigden1991
    trigden1991 Posts: 4,658 Member
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    To be honest I think I'll just ditch calculations and jus assume I need to cut my daily amount to slow down the rate of gain!

    Good plan. Somewhere between 0.5-1lb a week (towards the lower end) is a good rate of gain. Any more and you will be adding excess fat.
  • comptonelizabeth
    comptonelizabeth Posts: 1,701 Member
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    To be honest I think I'll just ditch calculations and jus assume I need to cut my daily amount to slow down the rate of gain!

    Good plan. Somewhere between 0.5-1lb a week (towards the lower end) is a good rate of gain. Any more and you will be adding excess fat.

    Yup tell me about it - not planning on posting pics anytime soon. :smiley:
  • comptonelizabeth
    comptonelizabeth Posts: 1,701 Member
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    Mycophilia wrote: »

    There's also articles that explain in more detail what the 3500 calorie rule is and how you should/shouldn't apply it. As with most things, there are some caveats to take into consideration.

    Thanks - I'll have a look!