Yet ANOTHER Study Debunking "fasted cardio"
Azdak
Posts: 8,281 Member
At least when it is promoted as a "fat loss" strategy.
This study was just published, and authored by some well-known names in the profession: Brad Schoenfeld, Alan Aragon, Colin Wilborn, and James Krieger.
It is important because it is one of the few studies (the first?) to compare the two approaches (fasted vs fed) over a longer period of time. Most studies on this topic have only looked at the ACUTE response during exercise.
Two groups did aerobic exercise for 60 min, 3 times per week, for what appears to be 4 weeks. Calorie intake was equal for both groups and was set at a 500 kcal/day deficity. One group exercised in a fasted state, the other was fed prior to exercise (250g replacement drink).
Both groups lost body fat, but there was no significant difference between the groups. In conclusion, the authors stated:
Journal of the International Society of Sports Nutrition 2014, 11:54 doi:10.1186/s12970-014-0054-7
The study results confirmed what exercise researchers already knew. Both Aragon and Schoenfeld have written articles arguing against fasted cardio in the past. While certainly not in the same universe as those two, I wrote in more detail on the topic about a year ago.
http://www.myfitnesspal.com/blog/Azdak/view/fasted-cardio-does-not-enhance-fat-loss-617168
Keep in mind that this research is only looking at fasted cardio as a fat loss strategy. This has NOTHING to do with whether or not individuals find it more comfortable to exercise in a fasted state, nor whether exercising fasted or not affects the quality of the workout. Those are separate topics and completely irrelevant to this discussion.
As I have said many times: if you prefer to exercise in a fasted state, NOTHING in this or other studies argues against that idea. The caveat is really only for those are doing it under the mistaken belief that it will cause them to lose more fat. The study didn't say "fed" was better--just that there was no difference.
This study was just published, and authored by some well-known names in the profession: Brad Schoenfeld, Alan Aragon, Colin Wilborn, and James Krieger.
It is important because it is one of the few studies (the first?) to compare the two approaches (fasted vs fed) over a longer period of time. Most studies on this topic have only looked at the ACUTE response during exercise.
Two groups did aerobic exercise for 60 min, 3 times per week, for what appears to be 4 weeks. Calorie intake was equal for both groups and was set at a 500 kcal/day deficity. One group exercised in a fasted state, the other was fed prior to exercise (250g replacement drink).
Both groups lost body fat, but there was no significant difference between the groups. In conclusion, the authors stated:
These findings indicate that body composition changes associated with aerobic exercise in conjunction with a hypocaloric diet are similar regardless whether or not an individual is fasted prior to training.
Journal of the International Society of Sports Nutrition 2014, 11:54 doi:10.1186/s12970-014-0054-7
The study results confirmed what exercise researchers already knew. Both Aragon and Schoenfeld have written articles arguing against fasted cardio in the past. While certainly not in the same universe as those two, I wrote in more detail on the topic about a year ago.
http://www.myfitnesspal.com/blog/Azdak/view/fasted-cardio-does-not-enhance-fat-loss-617168
Keep in mind that this research is only looking at fasted cardio as a fat loss strategy. This has NOTHING to do with whether or not individuals find it more comfortable to exercise in a fasted state, nor whether exercising fasted or not affects the quality of the workout. Those are separate topics and completely irrelevant to this discussion.
As I have said many times: if you prefer to exercise in a fasted state, NOTHING in this or other studies argues against that idea. The caveat is really only for those are doing it under the mistaken belief that it will cause them to lose more fat. The study didn't say "fed" was better--just that there was no difference.
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Interesting, thanks for sharing!0
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Not surprised by the results. That said, I lose more weight when doing runs first thing in the morning in a fasted state because I'm more likely to actually go on the run if I do it that way.
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Hundreds of bodybuilders from the 90s disagree with you. Strongly.0
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jofjltncb6 wrote: »Hundreds of bodybuilders from the 90s disagree with you. Strongly.
You mean they disagree with the study.0 -
Unfortunately, those bodybuilders are all n=1 examples and whose to say that if they did their cardio in a fed state with equivalent energy balance their results would be any different.
A few points on the study though. Even though 4 weeks is longer than the acute studies of the past it still is only 4 weeks. There was no statistical significance over the 4 weeks but would that still be the case after 12-16 weeks? (I dieted down to bb comp over 20 personally)
I still agree that you should just do your cardio (the minimum required for fat loss if you are doing it purely for aesthetics) whenever you can and don't sweat over the fasted vs fed stuff.
I had someone ask me this exact question the other day. Male and approximately 25% BF. Majoring in the minors.0 -
I prefer to do my workouts in the morning before I eat. I get better results.0
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chrisdavey wrote: »Unfortunately, those bodybuilders are all n=1 examples and whose to say that if they did their cardio in a fed state with equivalent energy balance their results would be any different.
A few points on the study though. Even though 4 weeks is longer than the acute studies of the past it still is only 4 weeks. There was no statistical significance over the 4 weeks but would that still be the case after 12-16 weeks? (I dieted down to bb comp over 20 personally)
I still agree that you should just do your cardio (the minimum required for fat loss if you are doing it purely for aesthetics) whenever you can and don't sweat over the fasted vs fed stuff.
I had someone ask me this exact question the other day. Male and approximately 25% BF. Majoring in the minors.
I don't have as much time to look at these things in detail these days, but I believe that the one instance in which fasted cardio might play a supporting role in better fat loss results in when you have someone who is very lean and needs to become extremely lean. I think Lyle McDonald goes into this on his site (and I think it forms part of the basis for his "stubborn fat" book.
The issue in fat oxidation vs fat mobilization. Unfit, obese individuals have plenty of fat available, but their ability to oxidize fat is impaired. Fit, very lean individuals have the opposite problem--they can oxidize fat, but can struggle to mobilize their fat stores. In this case, interventions such as fasted cardio, HIIT, and some supplements might have a more significant effect.
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jofjltncb6 wrote: »
I think she's referring to better results in performance and how she feels during the workout.0 -
I'd say using a word like "DEBUNKED" is jumping the gun. You forgot to mention that the study consisted of 20 women. ...Although peer reviewed, that's a very scant sample to generalized conclusion up to a general population.
All the women were screened to NOT be very overweight, they didn't have a lot of fat in the first place, so this study may or may not apply to young female in their 20's within healthy BMI range. It DOES NOT say whether that is valid for anyone outside these demographic variables.
" Subjects were 20 healthy young female volunteers (age: 22.4 ± 2.8 yrs; height: 163.4 ± 4.7 cms; weight: 62.2 ± 6.5 kgs"
They were also pretty fit it would seem from what the study says:
"All participants reported performing aerobic exercise several days a week on a regular
basis and several were off-season collegiate track and field athletes."
And the participants were performing LISS. Which might be an interesting variable changing fat loss numbers.
"Training consisted of 1 hour of steady-state aerobic exercise performed 3 days per week (...) increased intensity to 70% MHR for the next 50 minutes."
Burning fat cells only starts after 20 minutes of continuous exercise. I really wonder how that significant "fat loss" could occur. I've been taught that the total kcal burn is higher at higher intensity, and thereby also the fat burn. I tested it myself in 10 minute intervals. I burn 45 kcal at 70%, 55 kcal at 75% and a whopping 80 kcal at 80% almost doubling the burn. (the burns are low cause I'm old and not overweight anymore)
Also the fed group were younger than the fasted.
"The FED group was significantly younger than the FASTED group (21 ± 1.7 yrs versus, 23.8 ± 3.0 yrs"
The study concludes: "Percent body fat. There was no significant interaction between time and group, and there was no significant effect of group."
Body Fat%
FASTED-PRE 26.3 ± 7.9
FASTED-POST 25.0 ± 7.7
ES 0.17
FED-PRE 24.8 ± 8.4
FED-POST 24.1 ± 8.5
ES 0.08
I'm not an expert. But to me it looks like the BF% loss was HIGHER in the fasted group 26.3%-25%. While the fed group BF% loss was 24.8-24.7. Meaning the fasted group lost 1.3 in BF%, but the fed group lost only 0.7%.
I don't care if that is statistically insignificant. I'll take a 0.6% extra bodyfat loss for fasted cardio any day, ha-ha. Stated another way: If I can almost double my fat loss doing very low intensity cardio FASTED, compared to having been fed first, then that's something I should consider doing even more
If you wanna check the study yourself, here's the link:
http://www.jissn.com/content/pdf/s12970-014-0054-7.pdf
Edit: Formatted for better clarity. I wonder what their LBM loss was...the study doesn't say.0 -
Fasted cardio just makes me feel very sluggish and shaky. I'm not a fan!0
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I hate working out on an empty stomach. About a half an hour in and I am done (and cranky. and shaky). I like to eat a little something before and then a bigger meal later.0
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Foamroller wrote: »I don't care if that is statistically insignificant. I'll take a 0.6% extra bodyfat loss for fasted cardio any day, ha-ha.
Then you clearly don't understand statistical significance. 0.6% is far below the accuracy of ANY bodyfat measuring technique (except perhaps vivisection).
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I eat after. I feel sick to my stomach if I eat before. I drink water during the workout. I love working out first thing in the morning to get it out of the way.
I guess this study indicates that it is just personal preference.0 -
FunkyTobias wrote: »Foamroller wrote: »I don't care if that is statistically insignificant. I'll take a 0.6% extra bodyfat loss for fasted cardio any day, ha-ha.
Then you clearly don't understand statistical significance. 0.6% is far below the accuracy of ANY bodyfat measuring technique (except perhaps vivisection).
As I said. I don't care about statistical significance. I only care about the actual numbers
Edit: The study referred to by the OP, states that the group who performed FASTED CARDIO in LISS lost MORE BODYFAT than those who had a meal pre-workout within 4 weeks. Whether that is something which is universally true for the general population, we don't know.0 -
Foamroller wrote: »FunkyTobias wrote: »Foamroller wrote: »I don't care if that is statistically insignificant. I'll take a 0.6% extra bodyfat loss for fasted cardio any day, ha-ha.
Then you clearly don't understand statistical significance. 0.6% is far below the accuracy of ANY bodyfat measuring technique (except perhaps vivisection).
As I said. I don't care about statistical significance. I only care about the actual numbers
Derp.
Lack of statistical significance means that the difference in the results is no different than you would expect from random chance. If, instead of fasted/fed, they plotted the results by the color of their outfits, you find a similar result.
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I know the meaning of statistical significance. Now you remind me of why I'm very happy I never pursued an academic carrier.FunkyTobias wrote: »Foamroller wrote: »FunkyTobias wrote: »Foamroller wrote: »I don't care if that is statistically insignificant. I'll take a 0.6% extra bodyfat loss for fasted cardio any day, ha-ha.
Then you clearly don't understand statistical significance. 0.6% is far below the accuracy of ANY bodyfat measuring technique (except perhaps vivisection).
As I said. I don't care about statistical significance. I only care about the actual numbers
Derp.
Lack of statistical significance means that the difference in the results is no different than you would expect from random chance. If, instead of fasted/fed, they plotted the results by the color of their outfits, you find a similar result.
Anyway, I would say that if the scientist who made this study was after statistical significance, then why was the study comprised of only 20 participants, effectively making the numbers in each group consisting only of 10 individuals. It's also a bit concerning that although the participants were randomized. ALL the younger females were clumped into the fed group. Could a more spread population perhaps have differed the results? I don't know.
Could the fact that all the participants were not very fat, probably very athletic also give different results compared to, let's say BMI above 28 people.
Since you are so much more scholarly endowed than me, I'm sure you would know that a "study" of 20 people is NOT a big enough number to make conclusions about the GENERAL POPULATION. So based on that the whole study is not statistically significant whichever conclusion you want to believe is right.
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It clearly would not matter for weight loss since it is total calories and not how many fat calories are burned.0
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As was stated earlier, it would be interesting to see a study run over a longer period. However, with that being said, I don't believe results from fasted cardio are statisticaly superior compared to a fed state. I do believe that it is individual preference. If one can perform to the best of their abilities fasted, then go for it. If a fasted state inhibits performance, either mentally, physically, or both, then why even bother?
ETA: As was stated earlier, "majoring in minors"0 -
The study proves nothing based on the small demo of participants and the short duration. Plus, just based on the statistical significance, it would be impossible to get any real data because not matter what, the numbers would always be too close to call.
Personally, I do my morning runs fasted because, if I eat before running, I get gastro issues. I also do my strength training fasted for no real reason other than I don't want to eat at 5:30 AM. I'd rather eat after my workout at 7 AM.0 -
This is interesting. I guess I never thought fasted or fed cardio made a difference in anything but how you feel. I prefer to work out semi-fasted. If I work out in the morning, I do it fasted because I am usually not hungry for breakfast until I have been up for an hour or two anyway. My water aerobics class starts at 4:00 PM and I have found that I get a little nauseous if I have eaten within 2 hours of the class, unless I ate something really light like a slice of toast or handful of nuts. I usually have a Quest bar for my afternoon snack so I make sure I have eaten it before 2:00 on those days.
Whatever. It is working for me and I am satisfied with my weight and fat loss so far.
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What's the ES value column in the Table 2 ??
From this study one can't even conclude that the cardio has any effect on weight loss - after 4 weeks on a 500 cal/day deficit the average weight loss was 2.9 pounds ;-)0 -
For me, regardless of the study, I hate fasted cardio, I don't feel like I have the same amount of energy and end up cutting sessions short. So when im trying to cut it's harder on fasted as I don't burn as much as I do doing none fasted.0
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Is this the study that Schoenfeld recently submitted for review in May in believe?
ETA: Disregard. I answered my own question. I was waiting for this to come out.
In to see 1 group of people actually discuss the study vs the other group of people that want to state how they know fasted cardiovascular is better because they believe so. Should be interesting.
I think you are going to be disappointed.
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You forget that they are dosing on clen during this time of fasted cardio, so it MUST be true.jofjltncb6 wrote: »Hundreds of bodybuilders from the 90s disagree with you. Strongly.
A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 30 years and have studied kinesiology and nutrition
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You forget that they are dosing on clen during this time of fasted cardio, so it MUST be true.jofjltncb6 wrote: »Hundreds of bodybuilders from the 90s disagree with you. Strongly.
A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 30 years and have studied kinesiology and nutrition
Don't they also take "stuff" that increases their BMR back then?
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I believe this is why the myth gets passed on in the fitness industry. Most competitors that tout it are getting into mid to low single digit percentages of body fat for a competition and more than likely this subtle change has an impact on their overall look.chrisdavey wrote: »Unfortunately, those bodybuilders are all n=1 examples and whose to say that if they did their cardio in a fed state with equivalent energy balance their results would be any different.
A few points on the study though. Even though 4 weeks is longer than the acute studies of the past it still is only 4 weeks. There was no statistical significance over the 4 weeks but would that still be the case after 12-16 weeks? (I dieted down to bb comp over 20 personally)
I still agree that you should just do your cardio (the minimum required for fat loss if you are doing it purely for aesthetics) whenever you can and don't sweat over the fasted vs fed stuff.
I had someone ask me this exact question the other day. Male and approximately 25% BF. Majoring in the minors.
I don't have as much time to look at these things in detail these days, but I believe that the one instance in which fasted cardio might play a supporting role in better fat loss results in when you have someone who is very lean and needs to become extremely lean. I think Lyle McDonald goes into this on his site (and I think it forms part of the basis for his "stubborn fat" book.
The issue in fat oxidation vs fat mobilization. Unfit, obese individuals have plenty of fat available, but their ability to oxidize fat is impaired. Fit, very lean individuals have the opposite problem--they can oxidize fat, but can struggle to mobilize their fat stores. In this case, interventions such as fasted cardio, HIIT, and some supplements might have a more significant effect.
But for the average person just trying to lose weight and fat.................not so much.
A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 30 years and have studied kinesiology and nutrition
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Or did it without t3 and clen?chrisdavey wrote: »Unfortunately, those bodybuilders are all n=1 examples and whose to say that if they did their cardio in a fed state with equivalent energy balance their results would be any different.
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This discussion has been closed.
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