IF works worse for nearly every outcome, including compliance. I would not recommend it. It's worse for fat loss, muscle gain, performance (to the extent it affects performance), etc. I would, again, not recommend it.
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Intermittent Fasting Yayyyy
Let's say two diets are equal in every respect they can be equal (macros, total calories, food quality, etc.) only one is based on IF and the other is not. Let's also assume the person on IF is taking in BCAA's every 3-5 hours to hit his/her leucine threshold, and that the diet is manipulated such that his/her training performance isn't altered. For someone trying to lose as much fat as possible and lose as little muscle as possible, are there any reasons at all to prefer the IF diet, assuming the person's compliance for either diet is held constant? Is there anything at all about that "fasted window/state" that enhances fat loss relative to not being in that state?
If not (and I assume not), to avoid getting a mere "No" in response, could you briefly elaborate on the failings of those that argue that IF is advantageous for fat loss?
(I recently got in a verbal tussle with a co-worker that is IF-ing, claiming it doesn't speed up muscle loss and it expedites fat loss. Then again, he's also only eating ~1,000 calories a day, not taking BCAA's during his fasted state, and he's not setting up his diet such that it won't affect his workouts; hence, all of the assumptions above. I would like to "steal-man" the IF argument as much as possible before critiquing it.)
Thanks!
✓ Member
IF works worse for nearly every outcome, including compliance. I would not recommend it. It's worse for fat loss, muscle gain, performance (to the extent it affects performance), etc. I would, again, not recommend it.
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My response is just to repeat the second paragraph of OP. If you don't feel like elaborating (which I get), could you direct me to some sources that do elaborate?Originally Posted by Jordan Feigenbaum
Thanks
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I'll try and take a shot at this:
Jordan's take on IF, 2012:
http://startingstrength.com/resource...t-fasting.html
2016:
http://startingstrength.com/resource...-question.html
Also, sticking to a strict 8-hour eating window would not allow you to optimize MPS (?)
7 Rules to Optimize Protein Intake | Barbell Medicine
✓ Member
I guess I'm just wondering what you'd like me to elaborate about, ya know? There is just no appreciable benefit from doing it when looking at it big picture. Theoretically, the compliance could be improved with it for the right person, but the data does not support that either. So, when asked about it I'm like "Yea it doesn't work better than a non IF diet, there are real drawbacks including compliance, insulin sensitivity, BMR, and performance related outcomes- but if you're already married to IF then let's cut this conversation off right now because I don't really care."
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Well we're just all about the "why" here at SS so I guess that's what I was asking for. I'd like to be able to give my clients and friends who ask about IF more than just "Yea don't do it bc I heard a Coach/PhD I look up to say it isn't optimal." The help you guys and gals provide here is free and I appreciate beyond words the fact that it is free. So if I'm asking for more than what I'm paying for (nothing) then that's cool, just say that. I'm not so naive as to think you'll give me a 50 page dissertation explaining the cons of IF, but maybe some sources that can get me started on education myself.
✓ Member
I'm just trying to understand exactly what you're asking for, specifically. Do you want me to opine eloquently about all the drawbacks of IF? Do you want an editorial reflecting the current state of the data on the topic? Moreover, do you think that makes a compelling argument to your friends or clients?
I think the posts I've made in this thread are easily sufficient for that purpose (clients and friends), but perhaps you're asking for something more specific.
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I have friends that aren't satisfied with my coming back to them and saying, "My boy Feigenbaum ain't down with IF, and that's my argument against." It's not very compelling (and shouldn't be of course).
So..when you says it's not optimal for X, Y and Z, I'm just hoping you or someone else can point me in the sources backing that up--not bc I don't believe you but so I can have a deeper understanding of WHY it's not optimal. (Ex. "It's not optimal for insulin sensitivity." What study suggested that?)
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Sorry for the double post, but the support doesn't have to be a study, could just be a physiological explanation. (Ex. IF isn't optimal for BMR bc [enter physiological explanation].)
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The problem with these discussions is a meaningful definition of "intermittent fasting," first and foremost. In the literature it can mean anything from alternate day fasting to time restricted eating of wildly varying lengths. On the interwebs I think the most common iteration is arguably the 16/8 approach popularized by Martin Berkhan, and it's probably the most practical.
I think one of the better posts I've seen on the topic is at Martin Berkhan's site and is a review by Alan Aragon, who isn't a proponent of IF, though address the depth of research on the topic pretty well:
Intermittent Fasting: Where Are We Now? | Intermittent fasting diet for fat loss, muscle gain and health
Obviously Martin's comments are going to be biased as he's in business for himself pushing this diet, but Alan's review itself is quite good, and I don't think it's otherwise available (Alan gave Martin permission to publish it for free).
I think the worst thing you can say about IF is that it's not clearly superior to not IF for most stuff. In terms of it being *worse* for the items Jordan is indicating, I would have to assume that is coming from his personal experience, as the sum of literature doesn't really support any of those points to the best of my knowledge. As Alan alludes to in the article above, the most comprehensive review of the subject is probably this:
Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. - PubMed - NCBI
To quote the authors:
As above, there is a trend for it actually improving hunger, which in my mind is probably the reason people seem to really like it with respect to compliance when attempting to lose fat, which is the most common application of these diets. This would be a disadvantage while trying to actually gain weight, though.While intermittent fasting appears to produce similar effects to continuous energy restriction to reduce body weight, fat mass, fat-free mass and improve glucose homeostasis, and may reduce appetite, it does not appear to attenuate other adaptive responses to energy restriction or improve weight loss efficiency, albeit most of the reviewed publications were not powered to assess these outcomes. Intermittent fasting thus represents a valid--albeit apparently not superior--option to continuous energy restriction for weight loss.
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