Wednesday, June 2, 2010

Diet Mythology: Ancel Keys and The Fat Fallacy

Bad science breeds diet mythology. Somewhere along the way someone screws up. The screw-ups can range from borderline deception and outright idiocy to a more subtle kind that is not apparent upon closer scrutiny and careful reflection by a third party. Sometimes the devil is in the details.

In many cases the mass media is to blame. Dumbed down translations of results, coupled with soundbites taken out of context and comments from "experts," can easily distort the true meaning of a study. Sensationalistic headlines like "fruit is fattening" sells more papers than "HFCS in refined foods may cause weight gain".

Sometimes we are to blame. When looking for the next cutting edge diet strategy or pill to optimize fat loss and muscle gain, we tend to look for stuff that validates our theories or fantasies. We are prone to readily accept any evidence, however weak and vaguely presented, as long as it jibes with our own thinking.

Diet mythology

In this article series I am going to track the origin of diet myths and pinpoint where things got wrong. I thought it would be fitting to kick off with an old school myth that in some circles is still alive and kicking today. Even if it's old news to most of you, I hope you will find the origins of the myth interesting. It's an excellent example of how bias may warp the minds of scientists. Personally I find this stuff fascinating.

Future articles will reveal how people came to believe that breakfast is healthy, delve into the "30 g protein in one sitting"-myth, carbs and growth hormone, late night eating, among other things.

Fat, cholesterol and heart disease

I still see dietitians in the press media and television warning against the dangers of saturated fat. You have to wonder how long it's going to take until this myth finally dies completely.

The most notorious example of research gone wrong in the field of nutrition has to be that of Ancel Keys and his "Seven Countries" studies. I've mentioned Keys' groundbreaking work on starvation in the past: "The Minnesota Starvation Experiment", which resulted in the two-volume Biology of Human Starvation. Perhaps it was those impressive credentials that bought him so much trust and good will in the scientific community. As history would come to prove, even a brilliant mind like Keys's is susceptible to bias and error.

The birth of the fat fallacy goes back to the 1960's, when Keys started promoting a low fat diet to lower cholesterol levels. At that time he was in the process of finishing up the first study on cholesterol and heart disease. At this point he had convinced himself that there was a connection between fat intake, cholesterol and heart disease. He changed his stance slightly in the early 1970s , when he discovered that death in heart disease was best predicted by the intake of saturated fat specifically.

Keys needed stronger evidence for his hypothesis. Since he had already seen the connection in the "Seven Countries" study, it made sense to him that he would continue his work on the study over a longer time period. His findings were published in the 1980s and it was concluded that there was a connection between deaths from heart disease and serum cholesterol. Populations with a high saturated fat intake (U.S, Finland) had more deaths from heart disease, while populations with a low saturated fat intake (Greece, Italy) had fewer.

The fear of saturated fat had gradually been building up and reached its peak after the results of that study was made public. It was further compounded by studies showing a positive link between dietary fat, obesity and cancers in the early 1990s. By this time there seems to have been a mind shift in the public perception of fat - all fat was basically considered bad.

I wonder what Keys would think of the meal I had today: 1.2 lbs of fatty grilled pork rib goodness.

The mistake: Ancel Keys cherry picked his data to support a pre-existing notion he had about a connection between saturated fat, cholesterol and heart disease. Instead of choosing to continue his work in the seven countries from his original study, he should have selected other populations. When more and different data is added into the mix, the connection disappears. Keys seems to have been blinded by his own bias and wanted to validate, not investigate.

The consequences: Keys's findings resulted in the crusade against dietary fat in the 1980s and '90s. The message to the public was that dietary fat should be minimized and replaced with grains, and saturated fat replaced by unsaturated fat. Everyone started doing low fat, high-carb diets. On a related note, Keys's study also gave birth to the Mediterranean diet and the notion that people should adopt a diet rich in monounsaturated fat.

The truth: Many of the old theories about dietary fat and disease have now been contradicted by more rigorous studies that dispute the results, but it wasn't until about ten years ago the tide started to turn. It is now quite clearly established that there is no clear connection between fat intake, weight gain and many of the aforementioned disease states. Unfortunately Average Joes and Janes, especially those 40 years and older that don't spend their time debating nutrition on Internet forums, still think fat is "unhealthy". At least those I converse with.

Note: There are many nuances to Keys's story and I've only given a brief summary of the events which lead to the fear of cholesterol and fat. One book that covers the topic in great detail is Anthony Colpo's "The Great Cholesterol Con". It's an impressive piece of work and an excellent read.

Thoughts on dietary fat
and diet

Fat gain, heart disease and other modern maladies has everything to do with caloric excess and much less to do with dietary fat or any other macronutrient. For those of you who spend time nitpicking about what fat sources to eat for optimal health, consider this.

1. Reach and maintain the lean state first and foremost

Because for health, everything else is secondary. Lean people nearly always have excellent health markers. If you focus primarily on reaching and maintaining a lean state, your metabolic profile will be much better than if you had focused on perfecting the fat composition of your diet. Unfortunately, I know many people for whom the priorities seem reversed. Barring extremes it's an indisputable fact that fat loss does more for your blood lipids than weight maintenance with better fat sources.

Use whatever means you want to reach the lean state; whether you use a low-fat or high-fat diet is secondary to you reaching that objective. Then, maintain the lean state by adding weight slowly. An added bonus of that approach is that more of it will be muscle and less of it will be fat.

Adopting a whole foods approach helps in this endeavour. As it happens, the fat composition of a whole-foods diet is also favorable for health.

Everything is a go if it's an unprocessed food. Dairy is also fine. But eat only food you like and can live with in the long term. Is it not self-evident why am I telling you this? It seems not, because I often hear about how people force oil down their throat even if they hate it. So, if you don't like fish, eat beef. Can't stand avocados, eat eggs. You get the point.

Refined foods with a high fat content should not be an everyday diet staple. Besides diet compliance, there's the issue with trans fats and industrially processed oils present in these foods (which is what people should be concerned about).

My ideas on how to best approach maintenance of the lean state has been outlined in this article.

2. Eat fish or add fish oil to your diet

Even if you get your fats from unprocessed foods for the most part, your omega-6/omega-3-ratio is likely to be skewed towards omega-6. Unless you eat fatty fish on a regular basis, I would advise to add 3 g of fish oil per day. Doing so is prudent and may have modest health benefits in the long term.


KEn said...

Awesome, how many caloreis were in that fatty pork rib :)

LayzieBone085 said...

Maintain the lean state by adding weight slowly

*How slow is slowly? I know every trainer has a different recommendation as far as weight gain goes for a bulking/recomp diet, Your thoughts?

Also how much is too much when it comes to Fish-Oils per day? I currently take 6, 6 CLA and 3 Sesamin Caps.

How much is too much dairy? I usually eat 1 cup of cottage cheese a day and maybe 1 scoop of casein mixed into it with peanut butter before bed.

Thanks Martin, keep up the good work.

Adam said...

Fantastic article, really looking forward to seeing more in the "myth" series. Whatever the majority of people believe seems to become undeniable fact...I've given up trying to have a civil conversation with anyone about saturated fat. I'm a huge fan of fatty pieces of steak, and if I had a dime for every time I was told about how my "arteries are clogging" and I'm heart attack waiting to happen I'd be retired at 35.

Anonymous said...


From my admittedly rudimentary understanding of things, it would seem that saturated fat is only a potential issue in those with a genetic propensity towards expression of a small, dense LDL pattern, but in almost any other case, as you point out, saturated fat is anything but a bogeyman when you're not mainlining lard as your one and only source of calories.

-Bob Davies

Kat Eden said...

This is EXACTLY the sort of article ive been looking for as a useful reference and referral tool. I've been well aware of the Keys fallacy for some time, but sometimes have trouble explaining it to people. I love the way you've simplified, and look forward to the rest of the series!

PS - I'm a recent fan of IF, man does that stuff work! I've been trying to lose my pregnancy excess for months, and IF did the trick in 2 weeks the reality is that much of what we've been taught even about good, paleo nutrition is turning out to be too regimented for real results.

aequitas equitas said...

By far the best article on the "fat myth" that I have ever read. Not the most intracate but clear and to the point. Well done, Sir.

Darrin said...

Great post. The "low fat dogma" still, unfortunately, reigns supreme nearly 50 years on. We're gonna need as many nails in this coffin as possible. I look forward to reading the rest of the series!

Tan Yew Wei said...

Very Nice Martin. I'd assume the lean state refers to <15% body fat for males and <24% body fat for females. I'd also assume that to a point, being leaner isn't going to improve health markers further (ie: 10% body fat versus your ridiculously low body fat).

Looking forward to the future articles in this series.

Verbatim said...

Eye opening expose on the fish oil fallacy.

seand said...

Sorry, but I literally laughed out loud when I saw that your dinner had two tiny florets of broccoli... Why even bother putting them on the plate?

Martin Berkhan said...


No clue. 1000-1200 kcal or thereabouts. A lot of bone. I like chewing on them.


Depends. But you knew I'd say that. 6 g is fine. It's hard to go overboard on fish oil unless you're doing something completely retarded like Poliquins megadosing shit.

I have no clue what you mean by "how much dairy". Why would you want to limit it.



Martin Berkhan said...

Bob Davies,

Yeah, well, there's a lot to discuss regarding that depending on how much detail you want to cover and what/who you have been reading. But you're absolutely right in your last statement.

Kat Eden,

Thanks, glad you enjoyed the article and are getting great results with IF.

Martin Berkhan said...


15% is only considered the lean state if your goal is to be mediocre. Sure, it's the "healthy" standard for Average Joes but who the hell wants to be average.


Not so "eye opening" unless you have been swalling all the claims about fish oil hook, line and sinker. There are no miracle supplements. That doesn't mean supplementing with fish oil is useless.


I admit that it was mostly for show. I like broccolli though. But I also had a mountain of cottage cheese and a pound of berries waiting to be devoured after the ribs. I wanted to make sure I'd fit it in.

Dominik said...

Also interesting to read on this topic:

And I like your mindset, Martin :)

malpaz said...

reading up on some of your links and studies...of course i hand down agree with everything you said. the older laides i work with are currently eating their fat free oatmeal with skim milk, plus food every other hour b/c 'thats healthy'....anyways

so when your lean you assuming your healthy? this is the point i beg to differ on, especially for females.
if it is simply about how you look in front of a mirror, then yea anythings possible, but if you want health and leaness WITH reproductive abilities what kind of fat % do you find manageable in your women? how do their nutritonal and supplemental needs change? and their training schedules?

i am lean now
i would like to 'gain' some muscle
i dont have a period though, thoughts/suggestions?

sleepytechnics said...

hey martin,

another excellent article fcoz!

q how can you eat the cottage cheese? do you have some special ingredient or smt? because i cant get that stuph down my throat the way it is. one time i tried to mix it with whey and i almost puked. the brand i use is danone but i guess its always comparable taste. thnx. s.

Ryan said...


Love the site and am very curious regarding the LeanGains system.

Regarding fish oil, it's clear that certain benefits (namely the nootropic and mood/energy elevating ones) are probably overstated and unsupported by research, but as inflammation fighters and perhaps very minor recomposition aides there is significant research supporting them:

I was wondering if you could comment on the similarities of the LG system to the established fast fat loss systems as put forth by LMcD's rapid fat loss, biotest's velocity diet, and more general medical/bariatric interventions in the form of protein sparing modified fasts (PSMF).

I noted that it seems that protein only meals (or BCAAs) seem to have a certain "pass-through" effect with regards to altering the hormonal effects of fasting. Protein only meals in the fasted state also can result in significant GH elevations (

My question, then, is: could a system of extended fasting like leangains benefit in any anticatabolic/anabolic/fat loss way by incorporating a few BCAA or whey "pulses" in the fasted period, while maintaining a low caloric intake and zero carb/fat for the duration of the 16hr fast? I'd be concerned somewhat that this could disrupt the appetite suppressing catecholamines and reduce adherence. Your thoughts or experience in this matter would be great.

Lena said...

..not to mention the multi billion dollar industry that lives of Key's con; sponsoring studies supporting their products, influencing politicians and controlling much of the dumb a** lies we see in media.

Spot on as always Martin, will dig into Colpo's book.


Anonymous said...

Great read, Martin. I do want to bring up one very minute (and potentially moot) point that Lyle first brought up.

Lyle discussed some circumstantial evidence about how saturated fats are harder to mobilize. On a related note, there are no studies yet to show that although saturated fat is solid at room temperature, if it is completely liquid at normal body temperature (~10-15 degrees Celsius higher than room temperature).

Lyle stated that it might be possible to avoid the problem of stubborn fat in the future if saturated fat intake on subsequent bulks are curtailed. If adipocytes are predominantly filled with unsaturated fats as opposed to saturated fats during prolonged caloric excess, the idea is that the problem of fat mobilization in the single-digit BF% range is less likely to occur.

The practical "take home" points would sound to be:

1) Limit saturated fat intake during bulks
2) Saturated fat intake can be higher during cutting phases since it won't be deposited into adipocytes under hypocaloric conditions.

What do you think? Does Lyle's caveat have merit?

Again, my question helps to highlight the tendency for IF to avoid this problem anyway.


LayzieBone085 said...

The only reason I would limit dairy is because:

1) sometimes dairy products are more expensive then some poultry (chicken, tuna) depends if you can find sales (cottage cheese can be more expensive per serving.

2) Satiety (chicken/beef is more filling than cottage cheese or yogurt)

Martin Berkhan said...


"so when your lean you assuming your healthy?"

Generally speaking yes.

"this is the point i beg to differ on, especially for females."

Women are tricky in the sense that they don't suffer the same health consequences from being overweight as men, at least not before menopause, much due to more favorable fat deposition. The health improvements that can be had from going from normal body fat (~23-26% for women) to lower body fat are less predictable. Generally speaking, being leaner than the norm, which is inflated due to our sedentary lifestyle and nutrition, yields health benefits - but more so for men than men.

"if it is simply about how you look in front of a mirror, then yea anythings possible, but if you want health and leaness WITH reproductive abilities what kind of fat % do you find manageable in your women? how do their nutritonal and supplemental needs change? and their training schedules?"

Good question. Based on my personal experience this is subject to a lot of individual variation in between women. I know some who can maintain and function very well at 15% while others lose their period at that point. But this is subject to a lot of confounders - is it the body fat % who causes amenorrhea or is it the diet. Women often tend to pursue fat loss in an aggressive way and are prone to extremes. They also suffer more adverse sides than men in that the negative feedback signals/responses to extreme dieting are more pronounced.

Martin Berkhan said...


Try cottage cheese with something sweet - canned fruit, berries, honey, cacao, sweetener if you want to keep calories low etc. Goes down a lot easier that way

Martin Berkhan said...


To make a long story short, I think these "magical" nootropic and physiological effects of aminos are exclusive to protein-naive subjects. Look at the appetite-suppressing effects in naive and habitual consumers, for example. There's also evidence for tyrosine tolerance in studies on depression as I recall. They mention this in the discussion by alluding to a highly individual response:

"This indicates that personal response may be based on factors such as age, individual food preferences or training status, as described by Chromiak & Antonio (2002)."

But I admit that there's some weird stuff going on in that study. For example, the concomitant increase in HGH and insulin doesn't make much sense. Also note this part:

"In our model, increased hGH and decreased cortisol levels
after AA ingestion have an inhibiting effect on the synthesis of leptin."

Given that insulinogenesis = leptin synthesis usually, or maybe the measurements taken in this brief time period missed out to factor in the latent effect on leptin (5 hrs). Don't know, just briefly skimmed the study. Interesting stuff, but probably not applicable to people on a high protein diet since blood plasma AAs never really reach low levels like they do in protein-naive subjects after fasting.

Martin Berkhan said...

Btw Ryan, this was a big deal about 6-7 years ago but there's a reason that HGH-releasers never really took off as a supplement. Stuff just didn't work like it was supposed to.

Martin Berkhan said...


"Lyle stated that it might be possible to avoid the problem of stubborn fat in the future if saturated fat intake on subsequent bulks are curtailed."

Yeah, interesting theory. Who knows. It wont alter my stance on what people should be eating.

iiro said...

There's the link, not sure if I remembered to post it at the end of my comment. Cheers! - Iiro

iiro said...

Hello again, Martin

I have a question, I've tried to get my head around this issue but I'm afraid my expertise isn't up to snuff. I'm getting constantly better though! So I hope you'll find time to check out this article by Ray Peat. I have no idea how much critique this guy might warrant, but I'd love your insight on his views.

In short he's against serving people the idea of fish oils being beneficial. I don't think he relates to cholesterol in the sense the general public is driven to think ("Eggs are bad" "butter's bad"), but rather cancer and inflammation. And I know it's very contemporary to market everything as containing possible drivers for cancer, and since my understanding on these things is still very limited, I'd love to know what your take on this is.

Is it the omega3 that is the problem, or is it fish oil generally? He cites some research that claims that the fatty acids oxidize way before they enter the cells they're supposed to go to. Sorry if this seems like a dumb question.

Best regards, Iiro

Anonymous said...

I was wondering if I could vent something in here and maybe have someone comment it as well:

I've been trying IF for about one month now: not eating anything until two o'clock, and having three meals up until 9 in the evening, repeat. On training days; i eat most calories after workout, on rest days I eat most calories on the first meal.

Physically; the results are good. I'm getting more definition and not losing muscle, and this is something that I want to work as it suits my daily schedule and I like eating big when eating.

However, the part about 'after three days you won't feel much hunger anymore' is sadly not true. Even after having eating _big_, I'm still hungry in the mornings up until two o'clock, and I usually also feel a bit nauseous in these periods.

I've tried drinking coffee, and NOT drinking coffee, lots of water, less water, but the hunger is always there and so is the nauseous feeling.

Any hints on what I could do, or If I'm doing anything wrong? Or maybe IF just isn't for me? One would think that after one month the body had adapted to the changes, but it seems it still craves breakfast...

Martin Berkhan said...


I looked at the first three references in the article and then I quit reading.

2 out of 3 studies were on rats and one was just an oddity.

That's all I needed to form an opinon of the author. Someone who quotes rat studies as an argument against fish oil does no know what the hell he's talking about.

Rodent metabolism and their reaction to dietary interventions are a hell of a lot different than human models.

Humans evolved on a largely marine diet rich in omega-3 fatty acids. No such thing with rats.

Look at the studies that caused people to shun cholesterol - researchers based that on animal models where cholesterol were not part of their evolutionary diet.

Same thing with the DNL pathway. I could show you how carbs are fattening if I base that on animal studies (and some people love to do this) but yet that pathway is not very active in humans.

Conclusion: You can make all kinds of crazy claims if you base your argument on animal models/metabolism.

Martin Berkhan said...


"However, the part about 'after three days you won't feel much hunger anymore' is sadly not true. "

It's not true FOR YOU. Reason:

a) your diet setup is crap - too low on calories, protein, veggies etc.

b) IF is not for you.

Based on my experience, my money would be on "a".

sleepytechnics said...

@anon, martin,

i have been doing IF for about 2 months and i also get hungry at morning and noon. i guess this is because the body thinks its going to get food. while my stomach grawls i just drink alot and after a while it stops. i solve it by drinking alot of tea water or coffee. it stops and i just continu with the fast.
greetz s

Ben said...

Hey Martin,

I just picked up some VPX meltdown after re-reading your supplement guide. I want to get rid of some stubborn body fat and this stuff seems like it will help along with an IF regimen. I was wondering when you recommend taking it.

I fast from 8PM to 12PM and I am trying to decide whether to take it when I wake up (during the fast), with breakfast at noon, or before I work out (at about 2:00). Do you have a preference here?

Martin Berkhan said...

You'll want to take it during the fast, not after meals, since insulin negates the effects of yohimbine.

Fredrik Gyllensten said...

Yet another good article..
I've added the book 'The Great Cholesterol Con' to my 'to read' list.. Could you possibly write an article with your your top book recomendations?

I'm going over to Mexico nest week (from Norway), so I should be able to get a lot of reading during the travel..

I currently have this books etc. in my 'to read list' - your thoughts?

- Jamie's Ministry of Food (Jamie Oliver)
- Girth Control (Alan Aragon)
- Atomic Dog -- The Testosterone Principles (TC Luoma)
- Pumping Iron (Film, 1976)
- Assess & Correct (Eric Cressey, Bill Hartman og Mike Robertson)
- The Purposeful Primitive (Marty Gallagher)
- The Protein Book (Lyle McDonald)
- Optimal Shoulder Performance: From Rehabilitation to High Performance (Eric Cressey & Mike Reinold)
- Standing on the Shoulders of Giants (Intervjuer fra Nate Green)
- Bulletproof Knees (Mike Robertson)
- Living the Low Carb Life (Jonny Bowden)
- Nutrition and Physical Degeneration (Weston Andrew Price)
- The Great Cholesterol Con (Anthony Colpo)
- Zhekov IP and others, Weightlifting Training and Technique, Livonia Michigan, Sportivny Press, 1992

LD@DSD said...

The "fat is bad" crowd touts that since the reduction of saturated fat in America death by heart attack has dropped by a large percentage (i think like 40%). But the reason for this is not because we are having less heart attacks, but because the treatments and response for them has improved so much.

Berzinator said...

Good article supporting your article here Martin:

My name is Martin Berkhan and I work as a nutritional consultant, magazine writer and personal trainer.

Welcome to the Internet's leading resource on intermittent fasting and all things related.

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