How fast can fat be burned? I am not asking about how quickly weight can be lost but how much of a human's calorific need can be met by fat alone? Is it healthy to work at the maximum power output of fat for sustained periods?

1 Answer 1


Although it changes from person to person (weight), approximately 60-85% of maximal heart rate are accepted as fat burning zone. If you keep your intensity (lower is better) between above mentioned intervals, up to 70% of the calories burned can come from fat . This article may somewhat help you. Fat Burning During Exercise

how fast? do the math :-) every 45 minutes your run you lose 1 pound

  • That sounds very optimistic. Sorry. A kilogram of raw fat has 9300 kcal energy stored for the body. Therefore you would have to burn 4200 kcal in 45 min of runing. I guess that means running around near the sound barrier
    – Julian
    Commented Mar 14, 2016 at 9:05
  • Yes you are right :-) But in the answer I wrote; you lose 1 pound, not 1 pound of fat. May be I should have been more clear about it. Thanks for the correction.
    – bantandor
    Commented Mar 14, 2016 at 9:13
  • I should try. I sweat alot uring running. So I guess I can reach 1 Kilo per 45 minutes. But the weight loss will be 90-99% water then ( and a lot of pride when I realize how slow my running is)
    – Julian
    Commented Mar 14, 2016 at 9:15

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