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This is the first post by Greg Davis.
Modern Forager is no stranger to fasting, having reported on its potential benefits in several posts. But has one of the paleo/low-carb heavyweights, in Dr. Mike Eades, weighed in against the practice of intermittent fasting?
In one of his posts this month on his popular blog, “Intermittent fasting: Rad or Fad?”, Eades challenges the purported benefits of such a practice. Intermittent fasting, or IF, has been claimed by many to offer many benefits as reported recently in Scott’s post about his success story with IF. Eades himself experimented with an IF protocol back in the fall of 2007 and reported on it on his site. In his latest on IF, he has some harsh words including:
It’s looking like the intermittent fast is another of those ideas in science that look good in animal studies them not so good in human studies, proving once again that rats and mice aren’t simply furry little humans. And it appears - for humans, at least - that the intermittent fast is indeed beginning to look like the reality of a late-night gimmicky infomercial: long on promises, short on delivery. I suspect that it is also a cautionary tale about the applicability of caloric restriction studies to humans as well.
At first glance, given Dr. Eades stellar reputation and quality of writing, it seems quite a blow to those with high hopes for IF. But a closer examination of his rationale given for this newfound opinion reveals that what might really be saying is that IF is not an appropriate protocol for those seeking weight loss from their approach to diet.
IF fasting, by significantly decreasing thermogenesis, decreases kcal out because our thermogenesis is what burns a whole lot of our calories. If the kcal in are decreased by the IF and the kcal out are decreased by the diminished thermogenesis brought about by the IF, it’s no wonder the IF doesn’t result in a lot of weight loss for most people.
Dr. Eades is a foremost expert on what he is describing, which is called adaptive thermogenesis (link from Dr. Eades’ post). But its interesting to note the angle at which he is viewing the concept. Essentially we’re talking about a slowed down metabolism- a bad thing for weight loss right? Well, yes, probably. But what if weight loss is not your goal. What if you goal is to keep weight on? For many athletes and others using a low-carb approach, part of the appeal is the evidence that low-carb diets preserve lean body mass despite low caloric intake. There is an excellent post recently on the IF Life, Too Fast a Metabolism Accelerates Ageing, which covers many of the relevant issues of a slowed metabolism.
So in summary, the point I want to get across, is that there may not be a clear answer to the (poorly phrased) question “Is IF good or bad”? As with most things, it depends.
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Filed in Intermittent Fasting 13 Comments so far
Allen Yeh on 02 Apr 2008 at 9:39 am #
I know this topic has been talked about in depth over at the PM forum. But even in the weight loss area when I was IF’ing very consistently without the intention of being weight loss. I ended up losing 10+ pounds.
Keenan on 02 Apr 2008 at 9:58 am #
I think much of the problem is what is being eaten once the fast is broken. Dr Eades typically increased his carb intake significantly while intermittent fasting, snacking on foods he wouldn’t have otherwise. A healthy paleo diet coupled with IF should definitely enable one to lose weight. Specifically, IF seems to allow one to lose weight AND gain muscle at the same time, which is an interesting partitioning effect that would be of great interest to atheletes and bodybuilders.
Mike OD - IF Life on 02 Apr 2008 at 10:11 am #
Eades’ main IF issue was with the interpretation of the “general public”, not being able to magically lose weight with eating anything they wanted…which probably included high carbs and sugars. Even the Mattson study used to call out IF was based on people eating 1 meal a day high in carbs, that’s a disaster waiting to happen. While excessively low metabolism is not good, a slower one can definitely have advantages in terms of longevity. Like said above…IF + Paleo = Success….as many people can still gain muscle and lose fat, but the key factors are going to be #1) Multiple smaller meals (not one big one) in the eating window and #2)Making sure to get enough protein in the eating windows. IF on Crap (IFOC) will never have good results. Best part of IF…you make it to fit your lifestyle and needs. IF also offers advantages that an eating 6x a day plan can not (even if the calorie load is identical), namely greater improvements to fasting bloog glucose, fasting blood insulin and other neuro/cellular protective mechanisms that can improve heart/brain/lung function. If metabolic slow down the worry, then people should add in high calorie day(s) like say on the weekend. Metabolic slowdown is going to be an issue on most all diets as it is just based on calorie intake.
Erik on 02 Apr 2008 at 12:31 pm #
The link to Eades article is non-functional…
Scott Kustes on 02 Apr 2008 at 1:22 pm #
I think the key is definitely the food composition. While an IF on Crap is possibly better than a 6x a day on Crap, the true values of IF come from the foods that are being consumed. I’d rather see someone eat 6x/day, Paleo, than eat IFOC. Quality is by far the most important variable here.
Erik, thanks…link fixed.
Cheers
Scott
Manveet on 02 Apr 2008 at 8:44 pm #
All dieting comes down to is the amount of calories ingested vs the amount of calories burned or expended. You NEED to be in a negative calorie balance in order to lose any significant amount of weight or fat mass. I am fully aware of the thermic effect of food (most notably protein) but the extra amount of calories burned by simply eating more protein is of trivial importance when looking at the overall picture. It doesn’t matter if you’re doing South Beach, Zone, IF, Atkins, blah blah blah. All of these diets “work” by the very same principle of thermodynamics. If people are not losing any weight or fat mass on a diet they are simply eating too many calories or not expending enough (sans the few exceptional cases where people have some pre-existing medical condition).
So how does this all tie into IF? Well, it turns out that IF is just ANOTHER kind of dieting approach among the myriad of other dieting approaches out there. Is it better than other dieting approaches? Well, that depends. I’ve always been of the opinion that the best diet for anyone to follow is the one they can stick to for the long run. IF has been a successful strategy for many individuals. If you seem skeptical of this go check out the blog of Martin Berkhan over at leangains.net. He is a prime example that IF can be a successful strategy. Martin has been able to successfully integrate IF into his lifestyle. This does not mean IF is the greatest most amazing diet of all time. It just means that if someone can successfully integrate a reduced calorie diet into their lifestyle for the long run they will reap the benefits.
/rant.
Thanks!
Scott Kustes on 02 Apr 2008 at 9:24 pm #
Manveet, have you read Good Calories, Bad Calories? I think you’ll find a lot of information in that book to dispute the “Change in Weight = Calories In - Calories Out” statement you’ve just made. You should really check the book out. It can’t simply be Calories In vs Calories Out…if that were the case, why does excess calories in adolescence lead to growth of muscularity and bone structure while excess calories in later years leads to obesity? Here’s a word that it all hinges on: hormones. The wrong calories drive the wrong hormones which leads to the body either storing or releasing fat.
If it’s truly all about calories, then you agree that three individuals (assume all perfectly matched genetically and hormonally) will all fare equally as well on three different diets. Let’s put one on a diet of 2,000 calories from Twinkies, one on 2,000 calories from steak, and one on 2,000 calories from lettuce. Still think they’ll end up with the same change in weight? It’s often the ridiculous examples that prove the point. Furthermore, do you concur that individuals are ectomorphs, mesomorphs, or endomorphs? If so, that too disputes the notion of it being simply calories. If the body simply burned calories, we’d all burn them the same way and it would matter not what we ate. Bottom line is genetics and hormones influence the way we process the things we eat.
Martin has had great success with IF, as have I and quite a few others. It works very well because it’s an evolutionary setup. When you eat the foods your body is made for (Paleo foods) in a framework that your body is made for (feast-fast, such as IF), it all works beautifully.
Cheers
Scott
Manveet on 02 Apr 2008 at 10:49 pm #
Scott.
Your example about the difference in children and adults and how calories are partitioned isn’t a good one for two reasons.
1) Childhood obesity is on the rise. This is what happens when you eat many more calories than your body needs.
2) Adding hormones into the equation completely changes the scenario. It’s like asking me who is going to gain more muscle mass from the same diet: A natural bodybuilder or a bodybuilder using steroids? A growing child is “primed” for growth (much like the drug enhanced bodybuilder). A vast majority of the excess calories consumed will be partitioned to feed this growth. Adults are not primed for growth. Sure there is going to be a natural variation in the amount of hormones produced by an adult. But these differences are going to be almost trivial (aside from rare medical conditions) compared to difference seen at the hormonal level between a growing adolescent or child and an adult. It’s like comparing apples to oranges.
I’m only vaguely familiar with Taubes and his work. I’m not denying that you will see some small transient differences in the laboratory when feeding people on different foods (I understand the thermic effect of food) and the fact that protein affords the individual a slight metabolic advantage etc. However, these results have yet to be reproduced in the real world. Under controlled calorie conditions (re: not studies where individuals are required to REPORT their intake. We all know how great people are at tracking their food intake, right?) this seemingly slight metabolic advantage does not result in a significant difference in fat loss. I just don’t buy into any of these self report studies that show a metabolic advantage on a low carb/zero carb diet. In these cases people simply ATE LESS total calories. That’s what happens when you cut out an entire food source out of your diet (especially in North America where we love our pizza, beer, and assorted sugar-laden goodies).
Now, about your hypothetical example. First of all, nobody in the real world eats like that (at least I really hope they don’t). Secondly, provided that each individual was in caloric debt by the same amount, yes I would contend that there would be no significant difference in the amount of fat lost. Of course you will see some difference in total body weight lost (the guy eating lettuce leaves isn’t exactly doing as good of a job of sparing body protein as the guy eating steak) but overall I don’t think there will be a significant difference in total fat loss. I mean you can theorize all you want about insulin being chronically elevated in the twinkie diet and therefore that person won’t lose body fat and blah blah blah. But that’s just not how it’s gonna work out in the real world. Just think about it. Let’s say for these individuals their maintenance intake was 3000 calories. So with their 2000 calorie a day diet they have effectively created a 1000 calorie a day deficit. Now under these circumstances what use does the body have of storing extra energy at an appreciable rate? None. You’re starving. Just look at all of those starved individuals in Africa subsisting off a diet that contains little to no protein or fat and nothing but carbohydrates. Do they look like they are holding onto any appreciable amount of body fat? Of course not.
I understand the idea behind somatotyping. It’s actually a theory that no longer garners as much support as it once did back in the 1930s or 40s. I only agree with it to the extent that it maintains that human beings have a natural variation with respect to body size and shape. However, I contend that these differences are nowhere near as large and important as some people make them seem to be. Sure you may have a slight natural propensity towards endomorphism. But this can be changed through diet and exercise. Furthermore, the vast majority of individuals do not fall so neatly into these three categories.
Lastly, although I can’t speak for Martin, I’d say that his success was largely due to his consistency and commitment to following a plan. Note that I mentioned “a plan” in the sense that there are many ways to successfully diet, but all successful diets will REQUIRE you to eat less calories than you are expending. Many people have achieved Martin’s level of muscularity and leanness without IF. Hell, just looking at his raw numbers on how much muscle:fat he gained while using his approach it wasn’t very different from any other non-retarded approach towards muscle building. For more info on the specifics of this you can peruse the forums at bodyrecomposition.com/forums.
Whew, I think I covered all of the points there!
Manveet on 02 Apr 2008 at 11:06 pm #
Also, just another little point.
Martin used IF as a dieting strategy without any consideration to what evolution intended for our bodies. If you read up on some of the foods he ate during his diet (boxes of cereal, ice cream etc.) it certainly wasn’t in accord to current paleo/warrior diet lore.
Hey, he eat boxes of cereal nearly every other day and he still got lean. Surely what mattered were the overall calories and not necessarily where they were coming from (up to a point).
Scott Kustes on 03 Apr 2008 at 9:04 am #
Manveet,
You’re admitting that hormones play a part and then saying that they don’t. That sounds like a case of cognitive dissonance. You want to believe that it’s purely calories that matter, but your data is showing that it’s not. Why do the two genders fatten differently? Hormones. How about progressive lipodystrophy? Check out this video, and pay attention to the part on lipodystrophy around the 27-29 minute mark.
I’m not a big fan of somatotyping either. However, as you pointed out, it is illustrative that individuals deal with intake differently.
One other point…are you sure that calories in and calories out are independent variables? What if they aren’t? When calories in increases, people tend to become more energetic to burn them off. Similarly, when calories out increases (as through exercise), calories in tends to increase as well. In fact, exercise typically burns relatively few calories, but it primes the body hormonally. Why are calories after exercise preferentially shuttled to muscle growth while calories other times aren’t? Hormones.
The problem with the calories in vs calories out equation is that it relies on precision. Am I to believe that I’ve maintained my weight for the past decade by eating the same number of calories daily/weekly? What happens if I eat 25 calories too many each day? Further, you cannot say “Surely what mattered were the overall calories and not necessarily where they were coming from (up to a point)” and continue to contend that it’s merely calories. It either is or it isn’t…black/white. If junk food calories do not “perform” the same way in the body as whole food calories, it isn’t the calories.
Again, I urge you to read Good Calories, Bad Calories or at least watch that hour long video linked a few paragraphs up. If you read/watch it with an open mind, you’ll see that perhaps the equation is backwards. Taubes contends, and backs up with studies, that we don’t get fat because we eat too much, we eat too much because we’re getting fat. It’s a confusion of cause and effect. Just something to think about.
Cheers
Scott
Manveet on 03 Apr 2008 at 6:46 pm #
Scott,
Like I said before the examples you are using to defend your hormonal thesis on fat loss are too extreme to even be valid within the context of what we are discussing here. It’s like asking me who is going to gain more muscle on the same surplus of calories: a natural bodybuilder or a bodybuilder using steroids? I understand that hormones in large amounts will make a significant difference. That is precisely why bodybuilders use GH, insulin, AAS, and a whole host of other drugs to achieve a certain level of muscularity. However, what I am contending is that the natural variation in hormonal levels we see within certain subsets of the population (e.g. healthy adult males) is of trivial importance compared to the energy equation when it comes to fat loss. Trivial here doesn’t mean absolutely nothing. It means that it plays a very limited or minor role. And this has been supported through empirical evidence.
As to your second point about calories being preferentially shuttled towards muscle growth after exercising, do you think if someone exercising intelligently would be able to gain muscle mass off of a 1500 calorie a day diet? Of course not. Sure the individual may be creating an ideal hormonal milieu through training, but he wouldn’t reap any of the rewards without eating enough calories (provided that his aim were to gain muscle mass).
As to your third point the empirical evidence is in my favor. When studies have been conducted where calories are rigorously controlled and protein is adequate, varying carbohydrates or fats has a negligible effect on total fat loss. In fact I recall one study where calories where rigorously controlled but one experimental group received their carbohydrate intake from table sugar (sucrose) while the other group received their intake from starch. In the end both groups lost about the same amount of fat mass. Studies varying the sources of fat intake have had similar findings.
Now, I mentioned one caveat to all this. I mentioned the words “up to a point.” What I meant by this is that you may see some strange things happening to populations at the extreme ends of the spectrum. Namely individuals that are extremely lean (such as Martin) or extremely obese. But the vast majority of the population need not be concerned with this.
If you want to read a VERY good article that sums up my stance on this whole “is a calorie just a calorie” issue please read this short article on bodyrecomposition.com Here is the link: http://www.bodyrecomposition.com/Articles/calorieacalorie.html
I will have a look at Taubes’ book. I’d be interested in seeing what kind of evidence he uses to back up his claims. Although I have a sneaking suspicion that the studies he uses to support his points are not ones where calories were rigorously controlled.
Cheers
Manveet
Scott Kustes on 04 Apr 2008 at 7:38 am #
Manveet, seems as if we’re mostly in agreement, except for the little quibble over the calories issue. This is more of my feelings on the matter: it depends. Regardless, this is way off the path of the fact that smartly-implemented IF works and works well, as Martin, me, and others can attest.
I can tell you for certain that I maintain my 185lbs at a lower body-fat percentage on fewer calories than I did prior to IF simply because eating a day’s worth of calories in 4 hours is nigh impossible without gorging, an unhealthful habit for sure. It also seems that calories in and calories out are certainly not independent variables as my body temp. drops a touch during my fast and picks up markedly after I start eating. I reckon that is where the advantages of IF come in, enabling the body to run cooler and contributing to less metabolic wear-and-tear (much like running an engine too hot wears it out), while still maintaining the quality of life that the CR folks lose (lack of sex drive…who wants that?!).
In the end, all I really care about it what works. Whether it all boils down to calories or not is of little consequence to me, though as with all things relating to humans, I have a feeling that, “it depends” on any number of factors, including, yes, hormones and sensitivity to their actions. Perhaps amongst us “normal folks” calories are the end-all, but amongst the insulin-resistant, perhaps not?
Just a note that Lyle’s article threw in an extra variable that moves the discussion beyond simple calories: “adequate protein intake”.
Cheers and great discussion!
Scott
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