T Nation

Eating Healthy Doesn't Matter


The big one �? results of the biggest clinical trial of healthy eating ever

Everybody knows what it means to eat healthy. We�??ve heard about healthy foods and the importance of eating right our entire lives: �??To be healthy and prevent heart disease, cancers and other chronic diseases of aging �?? and to maintain a slim, �??healthy�?? weight �?? we should eat a low-fat and high-fiber diet with lots of fresh fruits and vegetables and whole grains.�?? This advice comes from respected doctors and health officials and we hear it everywhere, so it is unfathomable that these dietary beliefs have never actually been clinically tested...until recently.

While there have been decades of observational population studies and well-designed small trials that have disproven popular concepts of healthy eating, debates continued. Observational studies finding correlations between certain foods or diets and health benefits often turn out to be unsupported in clinical trials because foods and diets are frequently markers for the real things influencing health, such as genetics and social-economic status. Only well-designed clinical intervention trials can credibly demonstrate causation, correlations never can.

So, to settle the issue once and for all, one of the largest, longest and most expensive randomized, controlled, primary dietary intervention clinical trial in the history of our country was launched in 1993. This was to be THE study to end all studies and proponents believed it would finally prove the benefits of not just low-fat diets, but what has come to epitomize the government's very definition of �??healthy eating.�?? According to the National Institutes of Health, it was "one of the largest studies of its kind ever undertaken in the United States and is considered a model for future studies of women�??s health.�?? It was a major undertaking, costing $415 million and was conducted at 40 medical centers across the country. It was a well-designed and carefully conducted study and researchers were confident this would prove the rightness of eating �??right.�??

A lot was riding on this.

It was named the Women�??s Health Initiative (WHI) Dietary Modification Trial. A total of 48,835 postmenopausal women (the age most associated the risk for developing heart disease and cancers) were randomly assigned (with each group well matched) to either their regular unrestricted diet or to a �??healthy�?? diet that was low-fat (20% fat) and high fiber, with at least 5 servings of fruits and vegetables, and 6 servings of grains a day. The �??healthy�?? eaters endured an �??intense behavioral modification program by specially trained and certified professionals�?? to keep them on their diets. While they backslide a little, they did surprisingly well in sticking to the diet �?? as good as dietary prescripts will ever get and money can buy �?? at a cost of $8,498 spent per person!

The women in the healthy eating intervention group cut their total fat intakes down to 24% of their calories and 8% saturated fat the first year �?? well below the control group eating about 38% total fat and nearly 40% more saturated fats. By the end of the study, the �??healthy eaters�?? were still averaging 29% fat, compared to 37% in the control group. The �??healthy�?? dieters also ate about 25% more fruits and vegetables, grains and fiber than the typical American diet of the control group.

The researchers stated in their trial design that the dietary changes the participants made �?? while predictably not 100% compliant �?? were significant enough they were certain this study would find significant benefits, and confidently projected a 14% decrease in breast cancer, for example.

The women were closely followed for more than 8 years and the incidences of clinically confirmed breast cancer, colon cancer, heart disease, heart attacks and strokes were carefully monitored.

So what did this nearly decade-long clinical trial show?

Most of the study results were published at the beginning of last year, in a series of articles in the Journal of the American Medical Association. If healthy eating showed health benefits, the results would have been shouted far and wide. Since they weren�??t, you�??re probably beginning to guess that it failed to support long-held beliefs about �??healthy�?? eating. And you would be right.

More than 8 years later, there was no difference in the incidences of breast cancer, colon cancer, heart attacks or strokes among those who ate �??healthy�?? and those who ate whatever they pleased.

Cardiovascular disease (the biggest cause of death as we age)

Healthy eating proved to have no effect on cardiovascular disease. The researchers concluded: �??a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women.�?? (And among the women who had heart disease at the beginning of the study, the low-fat diet slightly increased their risks for heart disease.) Not surprisingly, as recently reviewed, the body of evidence reviewed by the American Heart Association in looking for support for its �??heart healthy�?? diets for the primary prevention of heart disease, found no support.

Breast cancer

Healthy eating proved to have no effect on breast cancer incidences. The researchers concluded: �??We found no evidence that lower intake of total fat or specific major types of fat was associated with a decreased risk of breast cancer.�?? (For those who might be quick to suggest that a �??healthy�?? and low-fat diet might have proven effective if begun earlier, the results showed that the women who�??d been eating the lowest fat diets before the study began had slightly higher risks for breast cancer than women who�??d been eating the most fat; while the women who had managed to most reduce their dietary fat fared the worst, with the highest risks for breast cancer.)

Colorectal cancer

Healthy eating proved to have no effect on colon or rectal cancers. The researchers concluded: �??a low-fat dietary pattern intervention did not reduce the risk of colorectal cancer in postmenopausal women during 8.1 years of follow-up.�??

Body Weight

Not only that, but the women following a �??healthy�?? diet for 8 years didn�??t end up thinner. They lost a bit at the beginning, but had regained it back years before the end of the trial, despite continued restrained eating and eating fewer calories (361 kcal/day less than they had been at the start of the study). During the last years of the trial and at the end, the researchers found an insignificant difference in weight changes between the intervention and control group of a mere 0.7 kg. They concluded: "A low-fat eating pattern does not result in weight gain in postmenopausal women."

More significantly, those in the control group who were not �??watching what they ate�?? and were eating whatever they wanted didn�??t gain weight, even though through the end of the trial they were eating more calories and fat than the dieters. Imagine how women who�??ve spent their lives denying themselves foods they love must feel. [Years of restrictive eating versus eating whatever you choose equals about a one pound difference in the end!]

The swiftness in which all of the �??healthy eating�?? and �??low-fat�?? diet interests rushed to issue press releases to spin the results of the WHI study was reminiscent of the same desperate reactions after the CDC Flegal et.al. study debunked the government�??s �??obesity�?? death statistics. But none of the spins or claims held up to the data, and the results of this huge study, despite the hundreds of millions of dollars of taxpayer money spent on it, were quietly buried. (This author sent out countless queries last year trying to find a publication, including a national size acceptance publication, that would print this and it was rejected. "We can't tell people that!")

To admit, �??We were wrong, never mind!�?? would crumble the entire house of cards.

And the myth of �??healthy�?? eating goes on as if nothing ever happened.

Beliefs that people need to be told to eat healthy and can't be trusted to eat right are equally entrenched, despite no scientific evidence in support for such dietary messages. In fact, the findings of the U.S. Preventive Services Task Force in 1996 and 2003 were that dietary counseling for healthy eating of adults or children lacked evidence.

The take-home message is that the soundest science for decades supports eating normally, enjoying everything, and not worrying so much. When we enjoy a variety of foods from all of the food groups �?? as most everyone naturally does when they�??re not trying to control their eating �?? and trust our bodies, we�??ll get the nutrients we need to prevent deficiencies. And that is the only thing that nutritional science can credibly support. The rest is dietary religion.

Health is not evidence of moral character and pristine diets. Don�??t let anyone try to scare you, threaten you, or get you to believe that if you don�??t eat �??right�?? (whatever their definition) you�??ll get fat, cancer, heart disease, or die sooner. There is simply no good evidence.

In Part Two, we�??ll look at the latest results of the WHI just released!

© 2007 Sandy Szwarc

posted by Sandy at 10/15/2007


This can't be right, surely?


Well it's not really saying anything new. We know that low fat diets don't work. There have been plenty of other studies showing that low fat diets aren't going to help you lose weight, although it is surprising that they weren't any healthier.

We need good fats in our diet and it's carbs that play a large role in body weight not fat.

I would also say they are correct to tell people to eat a variety of foods, to an extant. Clearly that variety of foods should not be made up of all the different junk foods, or fast food.

The study was only 8 yrs long, so 20yrs of eating like crap and then 8 healthy years won�??t undo all of the damage, not to mention I don't think you can relate 8 years of healthy eating to eating healthy for a life time!

To me, it sounds like someone put a spin on what the actual study is reporting and I would like to see the study as published without someone�??s comments on it.


Agree to an extent with crewpierce. Regardless, yes there has been a lot of debunking of the low fat myth. An article my dad sent me (a very un dietary person I might add):

(My statement edited for terrible grammar).

Diet and Fat: A Severe Case of Mistaken Consensus

In 1988, the surgeon general, C. Everett Koop, proclaimed ice cream to a be public-health menace right up there with cigarettes. Alluding to his office�??s famous 1964 report on the perils of smoking, Dr. Koop announced that the American diet was a problem of �??comparable�?? magnitude, chiefly because of the high-fat foods that were causing coronary heart disease and other deadly ailments.

He introduced his report with these words: �??The depth of the science base underlying its findings is even more impressive than that for tobacco and health in 1964.�??

That was a ludicrous statement, as Gary Taubes demonstrates in his new book meticulously debunking diet myths, �??Good Calories, Bad Calories�?? (Knopf, 2007). The notion that fatty foods shorten your life began as a hypothesis based on dubious assumptions and data; when scientists tried to confirm it they failed repeatedly. The evidence against Häagen-Dazs was nothing like the evidence against Marlboros.

It may seem bizarre that a surgeon general could go so wrong. After all, wasn�??t it his job to express the scientific consensus? But that was the problem. Dr. Koop was expressing the consensus. He, like the architects of the federal �??food pyramid�?? telling Americans what to eat, went wrong by listening to everyone else. He was caught in what social scientists call a cascade.

We like to think that people improve their judgment by putting their minds together, and sometimes they do. The studio audience at �??Who Wants to Be a Millionaire�?? usually votes for the right answer. But suppose, instead of the audience members voting silently in unison, they voted out loud one after another. And suppose the first person gets it wrong.

If the second person isn�??t sure of the answer, he�??s liable to go along with the first person�??s guess. By then, even if the third person suspects another answer is right, she�??s more liable to go along just because she assumes the first two together know more than she does. Thus begins an �??informational cascade�?? as one person after another assumes that the rest can�??t all be wrong.

Because of this effect, groups are surprisingly prone to reach mistaken conclusions even when most of the people started out knowing better, according to the economists Sushil Bikhchandani, David Hirshleifer and Ivo Welch. If, say, 60 percent of a group�??s members have been given information pointing them to the right answer (while the rest have information pointing to the wrong answer), there is still about a one-in-three chance that the group will cascade to a mistaken consensus.

Cascades are especially common in medicine as doctors take their cues from others, leading them to overdiagnose some faddish ailments (called bandwagon diseases) and overprescribe certain treatments (like the tonsillectomies once popular for children). Unable to keep up with the volume of research, doctors look for guidance from an expert �?? or at least someone who sounds confident.

In the case of fatty foods, that confident voice belonged to Ancel Keys, a prominent diet researcher a half-century ago (the K-rations in World War II were said to be named after him). He became convinced in the 1950s that Americans were suffering from a new epidemic of heart disease because they were eating more fat than their ancestors.

There were two glaring problems with this theory, as Mr. Taubes, a correspondent for Science magazine, explains in his book. First, it wasn�??t clear that traditional diets were especially lean. Nineteenth-century Americans consumed huge amounts of meat; the percentage of fat in the diet of ancient hunter-gatherers, according to the best estimate today, was as high or higher than the ratio in the modern Western diet.

Second, there wasn�??t really a new epidemic of heart disease. Yes, more cases were being reported, but not because people were in worse health. It was mainly because they were living longer and were more likely to see a doctor who diagnosed the symptoms.

To bolster his theory, Dr. Keys in 1953 compared diets and heart disease rates in the United States, Japan and four other countries. Sure enough, more fat correlated with more disease (America topped the list). But critics at the time noted that if Dr. Keys had analyzed all 22 countries for which data were available, he would not have found a correlation. (And, as Mr. Taubes notes, no one would have puzzled over the so-called French Paradox of foie-gras connoisseurs with healthy hearts.)

The evidence that dietary fat correlates with heart disease �??does not stand up to critical examination,�?? the American Heart Association concluded in 1957. But three years later the association changed position �?? not because of new data, Mr. Taubes writes, but because Dr. Keys and an ally were on the committee issuing the new report. It asserted that �??the best scientific evidence of the time�?? warranted a lower-fat diet for people at high risk of heart disease.

The association�??s report was big news and put Dr. Keys, who died in 2004, on the cover of Time magazine. The magazine devoted four pages to the topic �?? and just one paragraph noting that Dr. Keys�??s diet advice was �??still questioned by some researchers.�?? That set the tone for decades of news media coverage. Journalists and their audiences were looking for clear guidance, not scientific ambiguity.

After the fat-is-bad theory became popular wisdom, the cascade accelerated in the 1970s when a committee led by Senator George McGovern issued a report advising Americans to lower their risk of heart disease by eating less fat. �??McGovern�??s staff were virtually unaware of the existence of any scientific controversy,�?? Mr. Taubes writes, and the committee�??s report was written by a nonscientist �??relying almost exclusively on a single Harvard nutritionist, Mark Hegsted.�??

That report impressed another nonscientist, Carol Tucker Foreman, an assistant agriculture secretary, who hired Dr. Hegsted to draw up a set of national dietary guidelines. The Department of Agriculture�??s advice against eating too much fat was issued in 1980 and would later be incorporated in its �??food pyramid.�??

Meanwhile, there still wasn�??t good evidence to warrant recommending a low-fat diet for all Americans, as the National Academy of Sciences noted in a report shortly after the U.S.D.A. guidelines were issued. But the report�??s authors were promptly excoriated on Capitol Hill and in the news media for denying a danger that had already been proclaimed by the American Heart Association, the McGovern committee and the U.S.D.A.

The scientists, despite their impressive credentials, were accused of bias because some of them had done research financed by the food industry. And so the informational cascade morphed into what the economist Timur Kuran calls a reputational cascade, in which it becomes a career risk for dissidents to question the popular wisdom.

With skeptical scientists ostracized, the public debate and research agenda became dominated by the fat-is-bad school. Later the National Institutes of Health would hold a �??consensus conference�?? that concluded there was �??no doubt�?? that low-fat diets �??will afford significant protection against coronary heart disease�?? for every American over the age of 2. The American Cancer Society and the surgeon general recommended a low-fat diet to prevent cancer.

But when the theories were tested in clinical trials, the evidence kept turning up negative. As Mr. Taubes notes, the most rigorous meta-analysis of the clinical trials of low-fat diets, published in 2001 by the Cochrane Collaboration, concluded that they had no significant effect on mortality.

Mr. Taubes argues that the low-fat recommendations, besides being unjustified, may well have harmed Americans by encouraging them to switch to carbohydrates, which he believes cause obesity and disease. He acknowledges that that hypothesis is unproved, and that the low-carb diet fad could turn out to be another mistaken cascade. The problem, he says, is that the low-carb hypothesis hasn�??t been seriously studied because it couldn�??t be reconciled with the low-fat dogma.

Mr. Taubes told me he especially admired the iconoclasm of Dr. Edward H. Ahrens Jr., a lipids researcher who spoke out against the McGovern committee�??s report. Mr. McGovern subsequently asked him at a hearing to reconcile his skepticism with a survey showing that the low-fat recommendations were endorsed by 92 percent of �??the world�??s leading doctors.�??

�??Senator McGovern, I recognize the disadvantage of being in the minority,�?? Dr. Ahrens replied. Then he pointed out that most of the doctors in the survey were relying on secondhand knowledge because they didn�??t work in this field themselves.

�??This is a matter,�?? he continued, �??of such enormous social, economic and medical importance that it must be evaluated with our eyes completely open. Thus I would hate to see this issue settled by anything that smacks of a Gallup poll.�?? Or a cascade.


same ol' high carb low fat bs.


This entire study was based on the premise that low fat, high carb diets are "healthy".

Of course we know better. But the wheat lobby swings a lot of weight with the US government.


The only thing that study proves is that there's more to healthy eating than just fiddling with macros. Crew nailed it with the statement about trying to undo years of dietary abuse in a fraction of said time. I see people in the clinic here, all the time, who simply cannot comprehend why their obese, diseased, bodies are breaking down after 35 years of abuse. This was a suck-ass study. That's my professional opinion.





Good post.

Those interested in statistical reasoning, and the falsehoods often paraded as "epidemiology," will be interested in the PLoS article by Ioannidis. It is the answer to "why can't we ever know the truth?"

The article is an arcane bit of statistics, involving recursive reasoning, but it is important to those who may seek life choices on vague prescriptions and fashionable diets. Common sense is often a better guide than a poorly designed study.


There is nothing wrong with that study. It proved what many have know for years. Low fat/highh carb is not "healthy".

It seems that Confirmation Bias is stopping scientists from admitting the truth. I mean its hard to imagine the AHA admitting their diet is not effective and actually has been causing heart disease all these years.

Its easy to see how they got it so wrong.
Fats were just in the wrong place at the wrong time. Carbs cause people to be "fat",so people straight away associate "fatness" with dietary fat. People find fat in arteries and blame dietary fat, instead of the inflammatory effects of carbohydrates.

There is plenty of evidence out there but it is still going to take many years to reverse the old way of thinking.


C. Everett Koop?

"Lets talk about 'Def'... D-E-F... The thing that happens to you a few weeks after you has been alive. What is the odds that I is, one day, going to die?"

"You? 100 percent."

"Wait, now, isn't you being a bit of a pessimist?"


The problem is that it was assumed that low fat high carb diets were in fact healthy to begin with. People "in the trenches" so to speak have been ahead of science time in and time out. I hope next they do a multi million dollar study that shows that lifting weights will make someone strong.


Yea, 'they' can send the check to me. I'll be more than happy to conduct that study.



I totally disagree with what people are saying. I see this study as complete bullshit. I don't think they are saying what people in the "trenches" already know. I think the study horrible starting from the plan on how it was to be conducted.

Either this study was never conducted, or it was performed by an F student doing his thesis in nutrition(since it took him/her 8 years to complete it anyway, more time to drink at frat parties in school).

90% of obese people who sign up with a personal trainer and join a gym after new years don't last 3 weeks with something as simple as riding a bike for 20 minutes, or drinking 8 glasses of water a day.

Now you are going to tell me 50000 RANDOM Post Menapausal women had the drive to stick to a "HEALTHY" diet for EIGHT years? ....get the fuck outta heeerree.
Most menapausal women I know don't even care about anything and do whatever they please when they please.

Intense Behavioral Modification ? What the fuck? They hypnotized people?

"The researchers stated in their trial design that the dietary changes the participants made �?? while predictably not 100% compliant �?? were significant enough".
Are you kidding me?

The �??healthy�?? dieters also ate about 25% more fruits and vegetables, grains and fiber than the typical American diet of the control group.
0 * 25% = 0.

I'm sorry but this student would get an F for this study. You can end up with the wrong results in your lab but this was just horribly done.


There is a compelling bit of contemplation in here.


I dont know about the 50,000 women in this article, but I've switched from eating whatever I wanted (bulking cycle) to "eating healthy" (cutting) and I'm down almost 50 pounds and under 10% body fat. Surely I'm doing something wrong since I'm actually getting results.

They only cut 300 cals a day out of their diet over the course of the 8 years... I cut like 2,000 off my bulking diet when all was said and done. MOST people overeat, so cutting 300 cals a day out will probably barely put you in a calorie deficit... and surely after a few pounds lost you will no longer be in that deficit.

Why dont they look at what people like JB are doing with people and the type of eating he uses to get success with 90% of his clients?? I dont get it.