Exercise does not increase 24-hr fat oxidation

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Azdak
Azdak Posts: 8,281 Member
in Fitness and Exercise
This is a long article and some of the terminology may be challenging for those with no physiology background, however this is one of the most solid research overviews on the topic I have ever seen.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2885974/

I consider it a must read if you plan to make any comments about "fat burning" and exercise.

The author reviews a number of studies, including his own, showing that, regardless of what happens during the workout itself, exercise intensity has no effect on 24 hour fax oxidation. Nor does resistance exercise, but that is more difficult to study, so the results may be incomplete.

For anyone who likes to read research articles and has a passing interest in the topic, I think it is time well spent to work through this.

Replies

  • elmct57
    elmct57 Posts: 594 Member
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    my physiology class was 30+ years ago--you want to break it down for us?
  • fit2sit
    fit2sit Posts: 82 Member
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    That was a good read. I'm going to bookmark that for future reference. Its interesting to see that one can't get a great workout in and then cruise on the "fat burn" the rest of the day. Perhaps I missed it as it is a long read, or maybe they didn't add it, but I'm wondering how quickly the body returns the fat oxidation levels from post workout times. I would think it'd be a rather quick equilibrium as increased VO2 levels are returned to normal, fat oxidation would return to normal.

    I guess the only way to lose that fat is to hit the gym to increase fat oxidation during medium intensity exercising.
  • Kresent
    Kresent Posts: 39 Member
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    Thanks for the article. "We must educate the public that participation in moderate doses of exercise will not burn more fat unless changes are made to energy or fat intake." I like it.
  • chrisdavey
    chrisdavey Posts: 9,835 Member
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    "Our studies would suggest that energy and macronutrient intake is a more important modulator of daily fat balance, and therefore, that exercise recommendations made for the sake of regulating fat mass cannot be made without also considering energy and macronutrient intake. Unfortunately, we cannot at this time we cannot make recommendations of how energy and macronutrient intake can be modulated to induce negative fat balance. We can state with a degree of confidence that if energy intake is maintained below expenditure, than exercise will induce a state of negative fat balance. However, whether manipulations of macronutrient intake will be as effective remains to be demonstrated"

    Interesting :)

    Thanks
  • Azdak
    Azdak Posts: 8,281 Member
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    "Our studies would suggest that energy and macronutrient intake is a more important modulator of daily fat balance, and therefore, that exercise recommendations made for the sake of regulating fat mass cannot be made without also considering energy and macronutrient intake. Unfortunately, we cannot at this time we cannot make recommendations of how energy and macronutrient intake can be modulated to induce negative fat balance. We can state with a degree of confidence that if energy intake is maintained below expenditure, than exercise will induce a state of negative fat balance. However, whether manipulations of macronutrient intake will be as effective remains to be demonstrated"

    Interesting :)

    Thanks

    It's a fancy way of saying that it mostly boils down to: "energy in vs energy out" and "losing weight is 70% (or more) diet and 30% exercise".

    I especially liked that it was a 2009 article which made for a more up to date review.

    This meshes with other research reported in the last 10 years or so suggesting the limitations of exercise as the sole intervention for weight loss.

    It also supports my long-held contention that substrate utilization during exercise is irrelevant.

    What I would like to see is similar research performed following higher-intensity efforts like HIT or HIIT. Most of the studies looked at in the lit review seem to define "high intensity" as 70%-75% of VO2max.
  • adrienc
    adrienc Posts: 57
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    Thanks for the article - very instructive!
  • ShaneT99
    ShaneT99 Posts: 278 Member
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    We can state with a degree of confidence that if energy intake is maintained below expenditure, than exercise will induce a state of negative fat balance.

    In other words, eat less than you burn. Got it. :wink:
  • iplayoutside19
    iplayoutside19 Posts: 2,304 Member
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    In other words, You can't out excersise a bad diet!

    What I would like to see is similar research performed following higher-intensity efforts like HIT or HIIT. Most of the studies looked at in the lit review seem to define "high intensity" as 70%-75% of VO2max.

    Me too, I know from personal experience regardless if I've had a bad nutrition day, HIIT always gives me some awesome results in how I feel, and in looser clothing.
  • kennedar
    kennedar Posts: 306 Member
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    This makes a lot of sense. I tried to lose weight for 3 months using only the gym without any change in my diet. I gained a pound. While I lost some body fat, as a % it was very low. Within 3 weeks of watching my diet I have lost 6 pounds and feel like I am on a roll!
  • Azdak
    Azdak Posts: 8,281 Member
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    In other words, You can't out excersise a bad diet!

    What I would like to see is similar research performed following higher-intensity efforts like HIT or HIIT. Most of the studies looked at in the lit review seem to define "high intensity" as 70%-75% of VO2max.

    Me too, I know from personal experience regardless if I've had a bad nutrition day, HIIT always gives me some awesome results in how I feel, and in looser clothing.

    Keep in mind, the authors do NOT say that exercise does not help you LOSE fat--they are just saying it, by itself, does not increase fat oxidation. They say up front that their findings present somewhat of a paradox--we know that exercise helps, there is conflicting information as to the exact mechanism. The authors present some "maybe" ideas in the report and, as all good papers do, suggest areas for further research.

    So, this is definitely NOT a paper that discourages exercise as part of a fat loss program--it just questions some of the assumptions and cliches associated with the discussion.
  • iplayoutside19
    iplayoutside19 Posts: 2,304 Member
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    In other words, You can't out excersise a bad diet!

    What I would like to see is similar research performed following higher-intensity efforts like HIT or HIIT. Most of the studies looked at in the lit review seem to define "high intensity" as 70%-75% of VO2max.

    Me too, I know from personal experience regardless if I've had a bad nutrition day, HIIT always gives me some awesome results in how I feel, and in looser clothing.

    Keep in mind, the authors do NOT say that exercise does not help you LOSE fat--they are just saying it, by itself, does not increase fat oxidation. They say up front that their findings present somewhat of a paradox--we know that exercise helps, there is conflicting information as to the exact mechanism. The authors present some "maybe" ideas in the report and, as all good papers do, suggest areas for further research.

    So, this is definitely NOT a paper that discourages exercise as part of a fat loss program--it just questions some of the assumptions and cliches associated with the discussion.

    I agree, I've been active my entire adult life but continued to get fatter. It wasn't until I started counting calories that I made any progress.
  • adrienc
    adrienc Posts: 57
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    This makes a lot of sense. I tried to lose weight for 3 months using only the gym without any change in my diet. I gained a pound. While I lost some body fat, as a % it was very low. Within 3 weeks of watching my diet I have lost 6 pounds and feel like I am on a roll!

    I've got exactly the same story! It's only when I started counting calories that I started losing weight!
  • AwMyLoLo
    AwMyLoLo Posts: 1,571 Member
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    bump
  • Lyadeia
    Lyadeia Posts: 4,603 Member
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    It is very important to remember that nutrition and exercise work hand in hand to make you lose body fat. We must eat nutritious foods in order to fuel our muscles...properly fueled muscles are more apt to grow stronger and have more endurance while we exercise, and this in turn can increase our metabolism because it takes more fuel to make lean muscle do what it it does than fat. The more lean muscle you have, the more calories you are able to burn.

    But if we feed ourselves crap...then building all that muscle won't matter one single bit because we are still storing fat and not fueling ourselves properly in order to burn it more efficiently.

    Exercise is wonderful, but without proper nutrition, you'll be hard pressed to get anywhere. On the other hand, while you will lose weight simply by dieting alone, you would also be losing some lean muscle mass if you don't exercise it to make it grow...and this might make you skinny, but you will still have some health issues to deal with.

    We need both. :)
  • jillybeanruns
    jillybeanruns Posts: 1,420 Member
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    bump to read later

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