Why Low-Carb Diets Work

NOTE: This post is outdated.  I no longer believe everything I have written in this article.  I'll keep it up regardless, but it does not accurately reflect my current thinking.

Although it may seem counter-intuitive, a diet low in carbohydrates, which by definition is also higher in fat, may be the most effective way to lose weight.  I remember when I first heard of the Atkins Diet back in high school, when I saw my friend's father take the cheese off of a piece of pizza and throw away the bread.  Surely you can't lose weight by eating fatty cheese and throwing out the low-fat bread!  But while it made little sense to me at the time, low-carbohydrate diets really do work, and the science supporting this concept is just about indisputable.

Firstly, I would like to state that in weight-loss, what most people are concerned about is losing fat, as opposed to just weight in general.  Fat is the enemy, not muscle; we want to keep our muscle.  As a result, I'll be discussing how the fat tissue is regulated in the body.  In order to understand how low-carb diets help you lose fat, it is important to understand the function of two key enzymes that regulate the fat tissue:  lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL).  The activity of both of these enzymes is controlled by the hormone insulin, which is secreted in response to carbohydrate consumption.  I'm going to get into some biochemistry here... I like biochemistry because, since most people don't understand it, I can make it look like I really know what I'm talking about, even though in reality I'm just making up words and hoping I don't get caught.  Seriously though, it's important to understand a little basic biochemistry in order to truly understand how a low-carb diet burns fat like nothing else.

Why Low-Calorie, Low-Fat Diets Don't Work

NOTE: This post is outdated.  I no longer believe everything I have written in this article.  I'll keep it up regardless, but it does not accurately reflect my current thinking. 

Losing weight isn't easy.  Just ask your neighborhood middle-aged yo-yo dieter.  It's hard to get the weight off, and it's even harder to keep it off.  But the problem, in my opinion, does not lie in a lack of motivation or drive to make a successful lifestyle change.  The problem is that the vast majority of dieters are going about it the wrong way.  The media loves to promote this simple calories in, calories out model of weight loss, and while calories certainly do count for something, there's much more to the story.  What the calories in, calories out concept fails to account for is what your body actually does with the calories it receives, and it turns out that is a vitally important concept in weight loss. 

First off, let's discuss what happens when you try to lose weight by simply eating less (also known as starving yourself).  You start off with all the motivation in the world, probably counting calories and planning out all of your meals.  Let's say you aim to eat 1500 calories a day, and your body wants to burn 2500.  At this rate, according to the simple math of the calories in, calories out model, you should be losing about 2 pounds per week.  And indeed, you'll probably lose a few pounds in the first few weeks on a diet like this.  But you're setting yourself up for failure in the long-term.  Here's why.

5 Fake Health Foods

When people decide to "go on a diet", there are a number of so-called healthy foods that they typically turn to.  Some may be healthy, others simply are not.  But inevitably there are a few myths out there that just won't die, thanks in large part to clever advertising and labeling.  Heck, all food manufacturers have to do to convince people their product is healthy is to slap an "All Natural" or "Low in Fat" label on it.  Here is a short list of 5 of these "healthy" or "weight-loss" foods that dieters typically turn to and why they're not all they're cracked up to be. 


1.  Veggie Burgers

Ohhh veggie burgers... if I had a nickel for every time I've seen a health-conscious, well-intentioned dieter opt for a veggie burger instead of a real one... well I'd probably have about $10.  But that's a lot of nickels.  Veggie burgers are absolutely not a healthy alternative to beef burgers.  If you look up the ingredients of a typical veggie burger, like the Morningstar Farms Grillers Original burger, you'll learn that these things consist of largely soy and other isolated vegetable proteins.  This is a problem.  Soy is not a health food, especially when it's undergone as much processing as the soy in these burgers has.  There are too many risks of soy to fully explore here, but just to name a few...  1. Soy phytoestrogens disrupt endocrine function and have the potential to cause infertility and to promote breast cancer in adult women.  2. Soy phytoestrogens are potent antithyroid agents that cause hypothyroidism and may cause thyroid cancer.  3. In infants, consumption of soy formula has been linked to autoimmune thyroid disease.  4. Free glutamic acid or MSG, a potent neurotoxin, is formed during soy food processing and additional amounts are added to many soy foods.  Check out the Weston A. Price Foundation for more of this information.  Soy is not good for you, and veggie burgers are made up almost entirely of ingredients made in a food science lab.  Not a good choice.  Just eat a real burger.

Historical Context, Part 6 - The Obesity Epidemic

As I've talked about in previous posts, the government began making dietary recommendations in 1977, beginning with Senator George McGovern's Dietary Goals for the United States.  The torch was then passed to the USDA in 1980, which began drafting dietary recommendations every five years.  The most recent USDA Dietary Guidelines for Americans came out at the end of 2010.  For all intents and purposes, the recommendations have changed very little since 1977.  Let's look at some of the specifics of the government's advice here, and we'll see if Americans have been following it over the past few decades.  First on the list, avoid foods high in saturated fat.  This includes eggs (which everyone has been afraid of since that Time magazine article), red meat, and full-fat dairy.  And when you cut something out of your diet, you have to replace it with something else, right?  The government advised that we eat more starches, grains, and vegetable oils in the place of these high-saturated fat foods, along with more low-fat meats like chicken and fish.  Well, it turns out that Americans have been following this advice. Here are a few graphs showing the recent dietary trends:

Since the 1970's, we have done exactly what was recommended for us to do.  We've eaten fewer eggs, and keep in mind also that the egg data does not take into account the countless yolks that are thrown away for fear of their artery-clogging capabilities.  Until recently, an egg white omelet was a stupid idea, and rightfully so; it tastes awful.  We've reduced red meat consumption and replaced it with chicken and fish.  Red meat has become a poster boy for our health problems, but its consumption has declined as Americans' health has deteriorated over the past few decades.  Whole milk consumption has declined immensely.  Americans drink only about 1/3 of the whole milk that they did in 1970.  It appears as though most Americans have switched over to low-fat or fat-free milk, which have both increased dramatically over the same time period.  And then we come to grains, flour, sugar, and vegetable oil.  All three of these have been on the rise in the American diet over the past few decades.  Remember, the Dietary Guidelines recommended that we increase our grain consumption, and we did just that.  Unfortunately, in our attempt to avoid animal fat, we also consumed more sugar.  Sugar was something that was not stressed in the early Dietary Guidelines, but more recently the USDA has begun to recommend reducing sugar intake.  As for vegetable oil, I could not find a graph showing its consumption, but since it didn't exist before the mid 20th century and now it's considered an essential cooking item, it's safe to assume its consumption has increased exponentially. 

So... we followed the advice that was provided to us.  We ate less red meat and saturated-fat-laden foods.  We ate more grains and flour products.  We chose low-fat protein sources like skim milk and chicken breast, and we cooked with vegetable oils.  Well, here's what happened:

Obesity gone wild.   The first graph is from 1985, which was the first year obesity statistics by state were recorded.  In 1985, no state had an obesity rate over 14%.  Actually, data wasn't available for every state, but West Virginia, which has the highest obesity rate today, was under 14% in 1985, so chances are that was just about the highest in the country.  In 2009, only Colorado had an obesity rate under 19%, and there were 9 states with an obesity rate over 30%.  You could say, based on these numbers, that the obesity rate in America has approximately doubled since 1985, maybe even more than doubled.

But don't say it's because we're eating too much red meat and saturated fat, because we aren't.  Grains, sugar, and other carbohydrates are the foods that have been on the rise in America during this period in which obesity took off.  Besides, we have been eating red meat and saturated-fat-containing foods for millions of years.  The obesity epidemic, and the heart disease epidemic for that matter, only began in the 20th century.  As Sean Croxton of Underground Wellness always says, you can't blame new diseases on old foods.  I agree completely.  The culprits here are not red meat and eggs.  It is our overconsumption of grains, flour, sugar, and vegetable oils that is at the core of our health problems.

But what about the heart disease epidemic?  Did the recent dietary change prevent heart attacks?  It actually may have.  Heart disease rates have leveled off since the mid 1970's (see graph below).  Of course, there are other factors involved here, like the fact that everyone and their mother is on statin drugs, which may help prevent heart disease.  I'm not sold on statins at all, but there is some evidence that it's probably helping a few people prevent heart disease deaths.  It is important to note, though, that we are only talking about heart disease deaths.  Is a diet that can reduce your risk for heart disease, but increase your waistline and make your more susceptible to cancer, really the ideal diet?  I don't think so....

Now here we are in 2011.  The newest Dietary Guidelines have just been released, and we've still got a food pyramid that is based on a nutrient-poor food (grains) that hasn't been consumed for 99% of human history.  But what else is our government to do?  We as humans made a decision 10,000 years ago to commit to a grain-based diet when we adopted agriculture as our means for food production.  We sacrificed our health in return for the ability to support a greater population.  As a result, our modern government is obligated to support a diet that can feed the ever-increasing population; a diet based on grains that are high in calories and can be mass-produced fairly easily and inexpensively.  The USDA Dietary Guidelines will NEVER adopt a lower carb Paleo Diet mindset, regardless of how clear the science is.  Firstly, such a stark change in ideals would admit that they've been wrong for the past three decades.  Secondly, it would ruin the agricultural industry.  Thirdly, eating an optimal human diet is just not possible for everyone to do with our current population.  Like I said, we made the decision to eat a grain-based diet when we decided to adopt agriculture. 

So, to conclude this six-part Historical Context series, THIS is why I reject the low-fat concept, THIS is why I think the Dietary Guidelines are ridiculous, and THIS is why I eat the way I do.  I hope my position is more clear now.  Thank you and goodnight.

Historical Context, Part 5 - Inadequate Evidence

Following in the McGovern Senate Select Committee's lead, the USDA drafted its first official Dietary Guidelines for Americans in 1980.  The recommendations were strikingly similar to those of McGovern's recommendations, despite the fact that many of the organizations involved in food and nutrition, like the Food and Drug Administration (FDA), the National Academy of Sciences (NAS), and the National Institute of Health (NIH), had considered the original Dietary Goals to be largely a political document instead of a scientific one.  Now, solid scientific evidence was needed to support the low-fat diets they were promoting (that's a little backwards, no?).  In the early 70's, NIH administrators decided against conducting a $1 billion clinical trial that would likely offer a definitive answer to whether or not low-fat diets prolong life.  Instead, they opted to conduct a half-dozen smaller observational studies, at a third of the cost, that they hoped would provide the evidence they were looking for.  The results of these studies were published between 1980 and 1984.

Four of these studies tried to establish relationships between dietary fat and heart disease.  They observed populations in Honolulu, Puerto Rico, Chicago, and Framingham, Massachusetts, and although some of the data suggested an association with fat and heart disease, the data involving all-cause death revealed a different story.  In the Honolulu study, the researchers followed 7,300 men of Japanese descent and found that those who developed heart disease ate slightly more fat and saturated fat than those who didn't.  However, the men who actually died tended to eat less fat and less saturated fat, so low-fat diets were associated with increased mortality.  Similar results were seen in Framingham and Puerto Rico.  The researchers' interpretation of these results is absolutely astounding.  They reported that because men in Puerto Rico and Honolulu who remained free of heart disease ate more starch, the studies suggest that Americans should follow the Dietary Guidelines and eat more starch.  Consequently, in order to avoid eating too many calories, Americans should also reduce fat intake.  WHAT??  Talk about twisting the results to support your hypothesis...

And it gets worse.  Also found in this data, with the exception of the Chicago study, was an association between cholesterol levels and cancer rates.  That is, low cholesterol predicts higher cancer rates.  This link was not abnormal.  In fact, by 1980, this association was showing up regularly in studies like this.  But this connection seemed to present a problem for the diet-heart hypothesis and was never publicized the way it should have been.  Just ask someone on the street today if they've ever heard that high cholesterol may be protective of cancer... they'll probably laugh and walk away.  Regardless, there is a strong link there.  In the Framingham study, men whose total cholesterol was below 190 mg/dl were three times more likely to get colon cancer as men with cholesterol over 220 mg/dl, and they were almost twice as likely to get any form of cancer than those with cholesterol over 280 mg/dl.  This is not an anomaly.  It is in fact very typical of these types of studies.  Those who have higher cholesterol tend to have a slightly greater risk of heart disease, but those with lower cholesterol clearly have a greater risk of cancer, and often times a greater total mortality rate as well.

The National Heart, Lung, and Blood Institute (NHLBI) also published two studies in the early 1980's that were supposed to provide support for the diet-heart hypothesis.  The first was the Multiple Risk Factor Intervention Trial (MRFIT), which collected a group of 12,000 men who were considered at imminent risk of having a heart attack; they all had a total cholesterol level over 290 mg/dl.  The men were randomly divided into two groups, a control group and an intervention group.  The control group was told to live, eat, and address their health problems however they wanted, while the intervention group was counseled to quit smoking, take medication to control their high blood pressure, and eat a low-fat, low-cholesterol diet.  The men were then followed for 7 years.  The results, announced in October 1982, showed that there had been slightly more deaths in the intervention group than in the control group.  Also of note, despite the fact that 21% of those in the intervention group quit smoking compared to only 6% in the control group, the intervention group had more lung cancer.  The researchers attributed this to the fact that those on the low-fat diet had lower cholesterol levels, hence were more likely to succumb to cancer.  I would concur.

The other NHLBI study was the Lipid Research Clinics (LRC) Coronary Primary Prevention Trial.  This trial collected 3,800 men who had cholesterol levels over 265 mg/dl, considered imminently likely to suffer a heart attack.  All of the participants were counseled to eat a cholesterol-lowering diet, but half of them took a cholesterol-lowering drug called cholestyramine, while the control group took a placebo.  So, to clarify, the only difference between the two groups was the presence or absence of the cholesterol-lowering drug.  This means that the only variable being tested was the effectiveness of the drug, nothing else.  Here are the results:  In the control group, cholesterol levels dropped 4%, 158 men suffered non-fatal heart attacks, 38 died from heart attacks, and overall 71 men died.  In the group receiving cholestyramine, cholesterol levels dropped by 13%, 130 men suffered non-fatal heart attacks, 30 died from heart attacks, and overall 68 men died.  Putting the heart disease numbers aside, 71 deaths versus 68 deaths.  This means that the cholesterol-lowering drug had improved by less than 0.2% the chance that any one of the men who took it would live through the next decade.  Very insignificant.  Any right-minded person would wonder, then, how such an unimpressive cholesterol-lowering drug trial was featured in Time magazine as proof that cholesterol was a plague to us all, and that we need to lower our cholesterol by eating low-fat, low-cholesterol diets.  The heading of the article read "Sorry, It's True. Cholesterol Really Is a Killer."  Basil Rifkind, who headed the study, was quoted in the article as saying, "It is now indisputable that lowering cholesterol with diet and drugs can actually cut the risk of developing heart disease and having a heart attack."  That may be true, but it doesn't appear to save any lives, and that's the ultimate goal. 

I hope it is clear at this point that the research backing the diet-heart hypothesis is surprisingly thin.  You would think that for an entire nation to adopt these low-fat diets as the gold-standard in healthy eating, and most of the civilized world for that matter, there would need to be a wealth of research supporting it.   As I've shown here, the science is ambiguous at best, but by this point, the media had grabbed a hold of the low-fat diet so hard that it would never let go.  The USDA Dietary Guidelines for Americans are republished every 5 years and they're considered to be the most comprehensive, unbiased assessment of the science by many in the field of nutrition, even though they've barely changed since 1980.  Dietitians blindly take it as truth and implement it in their work often without questioning it.  To them I say, get some historical context.

Next time, in what will definitely be the last part of this Historical Context series, I'll wrap up all of this information in a nice, neat little package and attempt to bring it all together.

Historical Context, Part 4 - Dietary Goals for the United States

Probably the most influential event in the acceptance of the diet-heart hypothesis, the one that finally cemented the idea that we should all eat less fat and cholesterol, was the 1977 publication of Senator George McGovern's Dietary Goals for the United States.  This was, in McGovern's words, "the first comprehensive statement by any branch of the Federal Government on risk factors in the American diet."  In other words, until now, government had never told Americans what they should be eating.  Unfortunately, what led to the publication of these guidelines had little to do with nutritional science.

The influence of Ancel Keys on this process cannot be understated.  The man should take a large part of the credit (or blame) for convincing the country to fear fat, not just through his research but also through his influence on the American Heart Association (AHA), for which he was a board member.  As early as 1960, a full 17 years prior to the government recommendations, the AHA had begun recommending that Americans eat less saturated fat and cholesterol by avoiding red meat.  By 1970, the AHA had broadened their recommendations to all Americans (formerly they only applied to those with high cholesterol and smokers) and had begun an alliance with the vegetable oil and margarine manufacturers.  Two of these major manufacturers began distributing a "risk handbook" to doctors all over the country, touting the benefits of avoiding saturated fats and eating more polyunsaturated fats from vegetable oils like corn oil.  Doctors, of course, would begin passing this information along to their patients; all it took now was to add a label to a product saying "low in saturated fat and cholesterol" and poof! it's a health food in the public eye.  This alliance between the AHA and the vegetable oil manufacturers dissolved in the early 1970's due to research showing that polyunsaturated fats from vegetable oils and margarine could cause cancer in rats.  Nevertheless, the AHA was becoming more and more well-known by the public and would soon be considered a trusted source.  Today, you can find the AHA logo on such heart-healthy foods as Cocoa Puffs and Lucky Charms.

Another important political problem that was gaining momentum in the early 1970's was the problem of feeding the world's growing population.  The subject of famine in the third world was a constant presence in the news, where images of starving, impoverished children from all over the world were regularly shown.  A growing number of concerned individuals began blaming this world hunger on the wasteful American livestock industry.  The idea was brought to the mainstream through the popularity of a number of books, such as Diet for a Small Planet by Francis Moore Lappe and Appetite for Change by Warren Belasco.  According to Lappe, a 26-year-old vegetarian, the American beef industry required 20 million tons of soy and vegetable protein to produce two million tons of beef.  So, he argued, we would be doing the world's growing population a favor by bypassing this process and simply subsisting on the soy and vegetable protein ourselves.  This argument transformed meat-eating into a social issue, as well as a moral one.  Wrote Warren Belasco in Appetite for Change, "A shopper's decision at the meat counter in Gary, Indiana would affect food availability in Bombay, India."  In the eyes of these people, there wasn't enough food for everyone because the food industry was feeding it to cattle to support our meat-loving nation.  Coincidentally, this sentiment ran parallel to the AHA's stance that Americans should eat less saturated fat, especially red meat.  Just to clarify, I'm not some cold bastard who doesn't care about starving children in the third world, I'm simply trying to make the point that there were other factors at play in this whole diet-heart hypothesis deal that had nothing to do with recommending an optimal diet for health.  Besides, in 1968, before this public starvation scare even took hold, Norman Borlaug created high-yield varieties of dwarf wheat that had ended famines in India and Pakistan and averted the predicted mass starvations.  The hunger problem was already on its way to a solution.

And now we come to Senator George McGovern.  The aforementioned document, the 1977 Dietary Goals for the United States, was a product of McGovern's Senate Select Committee on Nutrition and Human Needs, a bipartisan nonlegislative committee that had been formed in 1968 with a mandate to wipe out malnutrition in America.  In its first five years, McGovern and his colleagues were very successful in implementing federal food-assistance programs to feed the hungry in America.  But by 1977, McGovern's Senate Select Committee was in danger of being reorganized and downgraded to a subcommittee, which would operate under the Senate Committee on Agriculture.  As investigative reporter William Broad explained it in a 1979 article, the Dietary Goals constituted a last-ditch effort to save McGovern's committee from reorganization.  The committee members knew that this was primarily a political move.  Committee staff director Marshall Matz was quoted as admitting, "We really were totally naive, a bunch of kids, who just thought, Hell, we should say something on this subject before we go bankrupt."  So McGovern and his committee decided to "just pick one" and support the diet-heart hypothesis, and recommend that Americans consume less fat and cholesterol.  The committee used the "changing American diet" story for the basis of its position, stating that at the turn of the century Americans consumed less fat and more carbohydrates, and heart disease was rare (refer to part 2 of this series for more on that).  Incidentally, they also loved Ancel Keys' Seven Countries Study (boooo.).They emphasized the need to return to the diet of the past, reducing meat and fat intake in favor of grains and other carbohydrates.

Now, put yourself in George McGovern's shoes for a moment... by endorsing the low-fat diet, you're winning on so many levels.  First, you're promoting the Senate Select Committee's reputation, not to mention your reputation as a politician.  Let's not forget politicians' obligation to make themselves look good.  Second, you're promoting a diet that can feed more people, the kind of diet that a government can get behind.  And third, you're giving the American people concrete advice to follow that you believe will improve their health.  The Dietary Guidelines were a culmination of all of these factors.  The major problem with the guidelines, however, was that now the public thought the debate was over; that fat and cholesterol were killers... and the science didn't support that.  The guidelines make it seem as though the data was clear, while in reality it was anything but.  Skeptics would continue to say that more research was needed in order to offer accurate advice, but unfortunately "more research needed" isn't particularly quotable or catchy.  The key concept to understand here is that the Dietary Guidelines for the United States was not a scientific document; it was a political one.  In the last part of this Historical Context series, I'll address the actual dietary research that refutes this low-fat and cholesterol dogma, and also discuss the ginormous impact that the Dietary Guidelines had on public opinion.

Historical Context, Part 3 - Ancel Keys

Ancel Keys, a University of Minnesota physiologist, deserves much of the credit for convincing the public that dietary fat and cholesterol are killers.  He initially became famous through his development of the "K-ration" for feeding combat troops in World War II; the "K" stood for Keys.  He then performed a series of human starvation studies and wrote the book "The Biology of Human Starvation", which made him a well-known, reputable nutrition researcher.  Originally, Keys did not believe dietary fat and cholesterol had anything to do with the rising heart disease rates, but his opinion changed when he attended a conference in Rome in 1951, where he spoke with a physiologist from Naples, Italy who boasted about the lack of heart disease in his city.  The diet in southern Italy was low in animal products, and the people there, especially the poor, tended to have lower cholesterol than those in the United States.  The rich in Naples, however, ate more meat, and had higher cholesterol levels and heart disease rates.  This convinced Keys for the first time that dietary fat from meat was driving the heart disease epidemic in the United States.

There were two key observational studies performed by Ancel Keys that ended up having an impact on the public's view of dietary fat.  The first, which many researchers did not taken seriously, was the 1953 study he performed involving six countries, comparing their fat intake to their heart disease rates.  The six countries he reported on (United States, Canada, Australia, UK, Italy, and Japan), showed a very strong association between fat intake and heart disease.  Now, of course, this is only an observational study and no cause and effect can be determined.  But the biggest problem with his study is that he left out the data from the 16 other countries for which data was available.  When all 22 countries are considered, his perfect correlation turns into a much weaker one.

Initially, in 1957, the American Heart Association (AHA) opposed Ancel Keys on the diet-heart hypothesis.  They wrote a 15-page report that year denouncing Keys and similar researchers for jumping to conclusions about the diet-heart hypothesis when there was no good evidence that it was true.  Less than four years later, in December of 1960, the AHA flipped their stance and adopted the diet-heart hypothesis as their new philosophy on heart health, proclaiming that "the best scientific evidence of the time" strongly suggested a low-fat diet, or at least replacing saturated fats with polyunsaturated fats, is preventative of heart disease.  What had changed in that four-year period?  Not the evidence.  There was no new evidence to either confirm or reject the diet-heart hypothesis.  What had changed is that Ancel Keys and Jeremiah Stamler, another supporter of Keys, had now made up two of the six members on the AHA committee.  Soon after, Ancel Keys was enshrined as the face of dietary wisdom in America in an article in Time magazine.  The article discussed Keys' idea of a heart-healthy diet as one in which nearly 70% of calories came from carbohydrates and just 15% from fat.  Despite the fact that there was ZERO evidence from clinical trials to back up this claim, the article only contained one short paragraph explaining that Keys' hypothesis was "still questioned by some researchers with conflicting ideas of what causes coronary heart disease."

The second important study done by Ancel Keys was considered to be his masterpiece, The Seven Countries Study.  This study is still, today, considered to be a landmark study because of the pivotal role it played in the acceptance of the diet-heart hypothesis.  Launched in 1956, Keys' followed 16,000 middle-aged men for over a decade and tracked their diets and their heart-disease risk.  The populations he chose came from seven countries:  Italy, Yugoslavia, Greece, Finland, the Netherlands, Japan, and the United States.  The results showed, again, a remarkably clear association, but this time the association was between saturated fat and heart disease.  Keys drew three conclusions from this study:  1. Cholesterol levels predicted heart disease.  2. The amount of saturated fat predicted cholesterol levels and heart disease.  3. Monounsaturated fats protected against heart disease.

Seems pretty clear huh?  Not quite... there are a number of problems with the study.  First and foremost, this is an observational study, and like I've said a million times, you cannot determine any causality from it.  Secondly, Keys chose countries that he knew would fit his hypothesis.  Had he chosen at random, he may have included countries like France or Switzerland that consume high amounts of saturated fat and have very little heart disease.  Third, we know now that middle-aged men are the only population for which total cholesterol numbers can predict heart disease, and the Seven Countries Study only looked at middle-aged men.  Lastly, and perhaps most importantly, Keys didn't look at total mortality, even though what we really want to know is whether or not we'll live longer.  Coronary heart disease accounted for less than a third of deaths.  He said himself in a 1984 follow-up paper, "little attention was given to longevity or total mortality."  Interestingly, if all-cause death had been taken into account, Keys would have found that the American population he studied lived longer than any other population with the exception of the Crete islanders, despite their high cholesterol. 

Even with all of the problems with Ancel Keys' research, his findings on saturated fat and cholesterol would have a profound impact on the public due to a sort-of perfect storm of events that would eventually lead up to the first government dietary recommendations, Senator George McGovern's 1977 Dietary Guidelines for America.  More on that in part 4!