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> Running burns about 100 Calories / mile[0] (62.5 Calories / km). Okay, at least that blog post is written by someone with a phd, but you can't really take th

> Running burns about 100 Calories / mile[0] (62.5 Calories / km). Okay, at least that blog post is written by someone with a phd, but you can't really take this at face value either. It's probably reasonably true in general (obviously still highly dependent on the person doing the running), but you seem to be assuming that this rate is the same on short runs and long runs, which sound suspicious. I wouldn't at all be surprised if the rate of energy expenditure increased as the time/distance of the race increased. Also if they're running instead of sleeping, I imagine that is probably increasing energy use as well. I'd also be pretty surprised it the 100 calories/mile was taking into account the person's resting metabolic rate. That could easily add another one to two thousand (more depending on the person) calories per day. Finally, even with your analysis coming to 1.5lbs of fat, that's quite a lot of fat in a trained athlete. I'd expect most of the men running these races are well below 10% body fat, and the lower your body fat is the more resistant the body tends to be when it comes to losing more. Losing 1.5 or more lbs of fat would probably be moving their body fat percentages down quite noticeably, which is not easy to do at such low levels. So maybe it is all bs, but I don't think it can be ignored so easily either.

nordsieck 7y ago
> I'd expect most of the men running these races are well below 10% body fat You're way off > This study compares body composition characteristics with performance among participants in a 161-km trail ultramarathon. ... Mean (+/-SD) BMI (kg x m(-2)) was 24.8+/-2.7 (range 19.1-32.2) for the men and 21.2+/-2.1 (range 18.1-26.7) for the women. Among the three fastest runners, BMI values ranged from 22.1 to 23.4 for men and 21.5 to 22.9 for women. [0] ___ 0. https://www.ncbi.nlm.nih.gov/pubmed/20222002 https://www.ncbi.nlm.nih.gov/pubmed/20222002
- atomical 7y ago
  You are confusing BMI with body fat percentage.
  - nordsieck 7y ago
    > You are confusing BMI with body fat percentage. I understand that they are different things. Unless these are bizarrely jacked ultra-marathoners, BMI should work just fine.
    - frickinLasers 7y ago
      For clarity, you could have just quoted the body fat percentages from the next couple sentences in the abstract. >> Mean (+/-SD) percent body fat values for men and women were 17+/-5 (range 5-35) and 21+/-6 (range 10-29) , and ranged from 6 to 14 and 14 to 27 among the fastest three men and women. I would imagine the fastest finishers are not "bizarrely jacked" (they usually look pretty scrawny), but their BMI is not very well correlated with their body fat percentage.
      - eredengrin 7y ago
        Also this line > We conclude that despite wide variations in BMI and percent body fat among ultramarathon participants, the faster men have lower percent body fat values than the slower men, and finishers have lower percent body fat values than non-finishers. So I do stand corrected that not all of them are significantly below 10% body fat, but some definitely were (I don't see a breakdown anywhere giving an indication of how many), including some of the top finishers. I'd also imagine the ones at higher percentages who performed well probably have higher floors to begin with for how little body fat they can reasonably reach. In any case, it is not at all abnormal for BMI to have nothing to do with body fat percentage or how jacked someone looks, especially with athletes. BMI is probably one of the most meaningless health metrics in common use.
      - dmix 7y ago
        Even further I'd imagine looking at the data for the top 30% of runners who are in the competitive tier this article is talking about would have more relevant and uniform data with narrower ranges.
    - runamok 7y ago
      I've gone to ultras. You really need to have a range for the elites vs. everyone else. It's a very inclusive sport and you have participants that are fairly overweight even. Based on what I recall from my college track days where I knew my teammates' body fat percentages (4% to about 10%) I'd estinate that most elite men are at the lower end of that. Also because most men have more muscle mass their metabolic resting rate is higher so that definitely could be part of the reason why women and men peak performance is so close in ultras. They are using 10 to 15% more calories per hour I'd estimate. Also on a hilly course they need to tote that extra mass up a lot of extra climbs. I am surprised no one has mentioned Ann Trason that won 13 (iirc) Western States and used to win many ultras outright.
deleted 7y ago
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nordsieck 7y ago

> I'd expect most of the men running these races are well below 10% body fat You're way off > This study compares body composition characteristics with performance among participants in a 161-km trail ultramarathon. ... Mean (+/-SD) BMI (kg x m(-2)) was 24.8+/-2.7 (range 19.1-32.2) for the men and 21.2+/-2.1 (range 18.1-26.7) for the women. Among the three fastest runners, BMI values ranged from 22.1 to 23.4 for men and 21.5 to 22.9 for women. [0] ___ 0. https://www.ncbi.nlm.nih.gov/pubmed/20222002 https://www.ncbi.nlm.nih.gov/pubmed/20222002

atomical 7y ago
You are confusing BMI with body fat percentage.
- nordsieck 7y ago
  > You are confusing BMI with body fat percentage. I understand that they are different things. Unless these are bizarrely jacked ultra-marathoners, BMI should work just fine.
  - frickinLasers 7y ago
    For clarity, you could have just quoted the body fat percentages from the next couple sentences in the abstract. >> Mean (+/-SD) percent body fat values for men and women were 17+/-5 (range 5-35) and 21+/-6 (range 10-29) , and ranged from 6 to 14 and 14 to 27 among the fastest three men and women. I would imagine the fastest finishers are not "bizarrely jacked" (they usually look pretty scrawny), but their BMI is not very well correlated with their body fat percentage.
    - eredengrin 7y ago
      Also this line > We conclude that despite wide variations in BMI and percent body fat among ultramarathon participants, the faster men have lower percent body fat values than the slower men, and finishers have lower percent body fat values than non-finishers. So I do stand corrected that not all of them are significantly below 10% body fat, but some definitely were (I don't see a breakdown anywhere giving an indication of how many), including some of the top finishers. I'd also imagine the ones at higher percentages who performed well probably have higher floors to begin with for how little body fat they can reasonably reach. In any case, it is not at all abnormal for BMI to have nothing to do with body fat percentage or how jacked someone looks, especially with athletes. BMI is probably one of the most meaningless health metrics in common use.
    - dmix 7y ago
      Even further I'd imagine looking at the data for the top 30% of runners who are in the competitive tier this article is talking about would have more relevant and uniform data with narrower ranges.
  - runamok 7y ago
    I've gone to ultras. You really need to have a range for the elites vs. everyone else. It's a very inclusive sport and you have participants that are fairly overweight even. Based on what I recall from my college track days where I knew my teammates' body fat percentages (4% to about 10%) I'd estinate that most elite men are at the lower end of that. Also because most men have more muscle mass their metabolic resting rate is higher so that definitely could be part of the reason why women and men peak performance is so close in ultras. They are using 10 to 15% more calories per hour I'd estimate. Also on a hilly course they need to tote that extra mass up a lot of extra climbs. I am surprised no one has mentioned Ann Trason that won 13 (iirc) Western States and used to win many ultras outright.

deleted 7y ago

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