When asking the question “does intermittent fasting work”, do you get the feeling that the ‘fat loss industry’ is getting desperate? And why shouldn’t it? In a context for which the basic formula for success can be as simple as “calories in/calories burned”, they need something more tantalizing to keep an audience spellbound and coming back for more. And what better way to do that than to simply reverse direction every few years? So what was once a hard and fast rule (i.e. eat 5 or 6 small meals a day) is now a scourge to avoid (i.e. “don’t do THAT; it doesn’t speed your metabolism and your body will adapt”).
As if with the predictability of seasonal change, we’ve now got the question “does intermittent fasting work”, which simultaneously raises the question of effectiveness of its seeming diametrical counterpart: “Does higher meal frequency work?” If they both “work”, which one works better? You’ve got to find yourself asking these questions if the “calories in/calories out” formula falls within the realm of mundane for you.
'Intermittent Fasting': Is it the best fat burning method or does it cause weight loss at the expense of calorie-burning muscle tissue?
But regardless of your affinity to the latest fat loss fads, you’ve got to honestly acknowledge a common phenomenon: the tendency among marketers of such fads to suddenly “pooh-pooh” what came before in favor of what’s hot now. Current proponents of intermittent fasting (IF) are all too quick to not just answer the “does intermittent fasting work” question in the positive, but to likewise claim that the frequent meal technique is abjectly ineffective.
So let’s not just investigate the “does intermittent fasting work” question; let’s also revisit whether the frequent eating of small meals works.
“Does Intermittent Fasting Work?” Or is it just a case of “out with the old?”
I recall as if it were yesterday even though it was in August of 2001. I was sitting in a trendy bar across from two of my stepbrothers in the popular Gaslamp Quarter of downtown San Diego. We were drinking lots of beer and discussing one of my stepbrother’s latest passions of the time – a disciplined adherence to Bill Phillip’s ‘Body for Life’ principles. What really resonated with Ron more than any other principle of the program was the recommendation of eating 5 to 6 smaller meals each day instead of the common 1 to 3 daily meals in which much of the population partakes.
“I’ve lost fifteen pounds of fat within a couple of months of doing this”, he said enthusiastically. “I’d have never guessed that eating more often could be so effective without trying it myself after reading the book. I’ve never heard of such a thing”
“That’s strange you’ve never heard of it”, I replied with sincere surprise. “Bodybuilders have been doing that for decades.”
And that’s a fact to consider when confronted with the hyped up sales material of those now pedaling the intermittent fasting protocol. It’s not enough for them to merely say that intermittent fasting works; they have to build its credibility by claiming its counter-practice (frequent meals) was wrong all along. But bodybuilders HAVE been using the ‘frequent meals’ technique successfully for decades. And so have millions of people who’ve lost fat and stayed lean using the 5-6 daily meals protocol outlined by any one of dozens of books.
In pointing this out, I’m not attempting to answer the “does intermittent fasting work” question in the negative; I’m merely saying its proponents are being dishonest in selling it from their decided premise – the notion that small, frequent meals have suddenly been found to be woefully ineffective.
“Does Intermittent Fasting Work?” First off… what is it anyway?
The term ‘intermittent fasting’ is actually pretty vague. That’s because its pivotal root word, ‘fast’, covers a range of applications. With even a basic knowledge of the English language, for example, we know that the word ‘breakfast’ is derived from the fact that we’re “breaking” our nighttime “fast” when we eat our first daily meal. Obviously, this implies that even the relatively short period of food abstinence we experience from 6 to 10 hours of sleep is considered fasting.
We also know that the inherent mystique surrounding an extended fast is nothing new. Every major religion places a special significance upon an adherence to fasting. We instinctively know that its practice is an immediate front-line denial of the flesh while its polar opposite (gorging) is, for many of us, a natural first response to hedonistic impulse. We’ve heard the health-nut crowd tell us (for decades) that fasting somehow “cleanses” our bodies – as if it evokes little Ajax scrubbers to surface in our blood vessels and give them the shine of a freshly cleaned kitchen countertop. (Haha… I’ve always wondered how long they imagine our “post-cleansed” eating takes to dull that shine away)
Now we’ve got a certain type of fasting that’s been labeled ‘intermittent fasting’ (IF). Of course, aside from being vague, the name is also a bit ridiculous because all fasting needs to be intermittent. The only other kind would have to be indefinite or “constant fasting” – which would leave us… well… dead, I think. Of course, we could also engage in a one-time fast, which would also result in no intermittency. But there wouldn’t be a point in doing that unless we discover we hate fasting on our first attempt at adopting its intermittent application.
Okay, with semantics discussions out of the way, let’s look at some common terminology used in the realm of ‘intermittent fasting’:
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ADF (alternate day fasting): Just as the name implies – alternating between a day of not eating with a day of… well, eating like a starving person (which you likely will be after a day of fasting). This is typically done in an eating/not eating pattern of either 24 hrs./24 hrs. or 36 hrs./12 hrs.
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Fast-Five Diet: A book by Bert W. Herring that outlines an intermittent fasting regimen of 19 hours of daily fasting coupled with 5 hours of daily eating time. Alternatively, there’s a similar intermittent fasting ratio of 20/4.
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CR (calorie restriction): This includes any type of reduction in calorie intake below a baseline of what was consumed regularly before the reduction. Thus, calorie restriction can be accomplished using intermittent fasting, moderate meal frequency, or high meal frequency.
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FFM (Frequent Feeding Model): The practice of eating 5 to 6 (sometimes as high as 8) meals per day as a method of eating fewer calories due to calorie intake that’s more commensurate with energy expenditure. Naturally, this is the method that now needs debunking in order to sell intermittent fasting. Funny… I can almost guarantee that the same people who are now lambasting this technique in favor of I.F. were once singing the praises of FFM as the ultimate answer to everyone’s fat-loss desires.
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Insulin Sensitivity: Is a term that refers to how well or poorly the body’s glucose-lowering response to insulin is working. ‘Insulin resistance’ (metabolic syndrome) is a condition of extremely low sensitivity to insulin that results in blood glucose levels that are consistently above normal. Insulin sensitivity relates to our discussion of intermittent fasting as it contrasts with the frequent feeding model because some proponents of IF are now attempting to discredit the FFM by claiming the latter lowers insulin sensitivity.
With that basic terminology as a foundation, let’s further investigate the question “does intermittent fasting work.”
“Does Intermittent Fasting Work”: If so… is it just due to cutting calories?
Those who are suddenly marketing ‘intermittent fasting’ are making bold claims that there’s science behind the practice. These claims are apparently based on just a few limited studies done on intermittent fasting. An abstract for a review of such studies, done by K.A. Varady, can be found right here.
In that review, done in November 2010 at the University of Illinois Chicago’s kinesiology department, the effects of daily CR were compared with those of intermittent CR. Daily CR is considered any daily calorie reduction of 15% to 60% below normal intake. Intermittent CR, in this study review, is 24 hours of ad libitum (volitional intake) food consumption intermittently altered with 24 hours of complete or partial food restriction. In other words, it’s slightly modified ADF (alternated day fasting); modified to the extent that “fasting” on the non-eating day did not necessarily involve the complete elimination of food. The study review was to determine the effects of each of these respective CR techniques on weight loss, fat loss, and lean mass retention in overweight and obese individuals.
According to this review, the two methods were comparable in overall fat loss effectiveness with the intermittent CR method possibly being more effective for retaining lean body mass. Granted, the review only had short-term study comparisons (4 to 12 weeks) for contrasting the effects of lean mass loss to fat mass loss between the two CR methods being compared. However, within this time frame, the daily CR studies showed 25% of weight loss attributable to loss in lean mass, whereas the intermittent CR studies showed 10% of weight loss attributable to loss of lean mass.
Wow, one would think a finding like this would have bodybuilders in droves trading their 5-6 meals of daily CR for a “starving day/feasting day” alternative. Why isn’t THAT happening?
For one thing, the studies being reviewed have their flaws. When examining the entire review, one finds that body fat was measured using a different method for those who participated in the daily CR protocols than was used for the intermittent CR participants. Daily CR people were tested mainly with duel energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI). Intermittent CR groups were tested mostly with bioelectrical impedence analysis. The difference in accuracy between the two methods is enough to create variability in findings that compare the two diet methods.
Another reason for raised eyebrows among bodybuilders and fitness enthusiasts being presented this finding is a lack of research on the effects of intermittent CR (or ADF) for those engaged in exercise protocols. Fasting, or any severe calorie restriction, can obviously expose the muscles of a recuperating bodybuilder or athlete to the ravages of catabolism.
This is something to consider for anyone asking the “does intermittent fasting work” question – especially given the importance of muscle building to counter sarcopenia in one’s quest for long-term leanness.
“Does Intermittent Fasting Work” because FFM doesn’t increase metabolism?
Those who are hell-bent on selling us intermittent fasting as a better fat loss method than FFM are quick to rationalize their claims by bringing up the topic of insulin. They say that “insulin stores fat” and “frequent eating raises insulin.” They basically make the following claims to sell their alternate diet philosophy:
- Eating 5 to 6 meals doesn’t really boost metabolism
- Eating 5 to 6 daily meals raises insulin
- Eating 5 to 6 meals suppresses ghrelin
- Ghrelin is a stimulator of HGH (human growth hormone)
- Insulin is a suppressor of HGH
- Fasting is a stimulator of ghrelin and HGH
- HGH is a fat burning hormone
- Thus… intermittent fasting burns fat and FFM makes you fat
“What?”
In truth, ANY eating raises insulin and the degree it’s raised is more dependent on the insulin sensitivity of the individual and the size/composition of the meal. When we fast and then gorge ourselves with food, we get an insulin spike. When we eat frequent meals that are too big and comprised of sugary food choices, we get an insulin spike. If we eat frequent meals but keep them relatively small and low glycemic, we can get less of an insulin spike and less daily net insulin levels than too much sugar with either IF or FFM.
Furthermore, who among us adopts or recommends the frequent meal model under the assumption that it directly boosts metabolism? It indirectly boosts it by helping build calorie-burning muscle tissue with the providence of catabolism-preventing nutrients for recuperating muscles on a steadier basis. I’ve personally always seen it as a tactic to both make calorie intake more easily commensurate with calorie expenditure while simultaneously keeping the body in positive nitrogen balance. Although the required frequency of meals might be excessive at a point, we know the overall method is effective due to extensive anecdotal evidence from years of practice among bodybuilders and fitness contestants.
And even though ghrelin, low blood sugar, and training in a fasted state might stimulate more HGH release, we can’t just assume that this effect overrides any negative effects of tissue catabolism from mini-starvation periods. It might; it might not. It actually might occur to a very limited extent with the law of diminishing return kicking in at a very specific time.
Is there currently enough “science” to know when that time is? No… there’s not.
With that said, please leave us your comments if you’ve used intermittent fasting to lose body fat – especially if you’ve done it while attempting to build or preserve muscle mass.




