How to Design Saturated Fat Studies to Hide the Truth

NF-Oct4 Saturated Fat Studies Set up to Fail.jpeg

Where do the international consensus guidelines to dramatically lower saturated fat consumption come from? (I show the list in my video, The Saturated Fat Studies: Buttering Up the Public). They came from literally hundreds of metabolic ward experiments, which means you don't just ask people to change their diets, you essentially lock them in a room--for weeks if necessary--and have total control over their diet. You can then experimentally change the level of saturated fat consumed by subjects however you want to, and see the corresponding change in their cholesterol levels. And the results are so consistent that you can create an equation, the famous Hegsted Equation, where you can predict how much their cholesterol will go up based on how much saturated fat you give them. So if you want your LDL cholesterol to go up 50 points, all you have to do is eat something like 30% of your calories in saturated fat. When you plug the numbers in, the change in cholesterol shoots up as predicted. The experiments match the predictions. You can do it at home with one of those home cholesterol testing kits, eat a stick of butter every day, and watch your cholesterol climb.

These ward experiments were done in 1965; meaning we've known for 50 years that even if you keep calorie intake the same, increases in saturated fat intake are associated with highly significant increases in LDL bad cholesterol. Your good cholesterol goes up a bit too, but that increase is smaller than the increase in bad, which would translate into increased heart disease risk.

So if you feed vegetarians meat even just once a day, their cholesterol jumps nearly 20% within a month. To prevent heart disease, we need a total cholesterol under 150, which these vegetarians were, but then even just eating meat once a day, and their cholesterol shot up 19%. The good news is that within just two weeks of returning to their meat-free diet, their cholesterol dropped back down into the safe range. Note that their HDL good cholesterol hardly moved at all, so their ratio went from low risk of heart attack to high risk in a matter of weeks with just one meat-containing meal a day. And indeed randomized clinical trials show that dietary saturated fat reduction doesn't just appear to reduce cholesterol levels, but also reduces the risk of subsequent cardiovascular events like heart attacks.

So we have randomized clinical trials, controlled interventional experiments--our most robust forms of evidence--no wonder there's a scientific consensus to decrease saturated fat intake! You'll note, though, that the Y-axis in these studies seen in my video The Saturated Fat Studies: Set Up to Fail is not cholesterol, but change in cholesterol. That's because everyone's set-point is different. Two people eating the same diet with the same amount of saturated fat can have very different cholesterol levels. One person can eat ten chicken nuggets a day and have an LDL cholesterol of 90; another person eating ten a day could start out with an LDL of 120. It depends on your genes. But while our genetics may be different, our biology is the same, meaning the rise and drop in cholesterol is the same for everyone. So if both folks cut out the nuggets, the 90 might drop to 85, whereas the 120 would drop to 115. Wherever we start, we can lower our cholesterol by eating less saturated fat, but if I just know your saturated fat intake--how many nuggets you eat, I can't tell you what your starting cholesterol is. All I can say with certainty is that if you eat less, your cholesterol will likely improve.

But because of this extreme "interindividual variation"--this wide variability in baseline cholesterol levels for any given saturated fat intake--if you take a cross-section of the population, you can find no statistical correlation between saturated fat intake and cholesterol levels, because it's not like everyone who eats a certain set amount of saturated fat is going to have over a certain cholesterol. So there are three ways you could study diet and cholesterol levels: controlled feeding experiments, free-living dietary change experiments, or cross-sectional observations of large populations. As we know, there is a clear and strong relationship between change in diet and change in serum cholesterol in the interventional designs, but because of that individual variability, in cross-sectional designs, you can get zero correlation. In fact, if you do the math, that's what you'd expect you'd get. In statistical parlance, one would say that a cross-sectional study doesn't have the power for detecting such a relationship. Thus because of that variability, these kinds of observational studies would seem an inappropriate method to study this particular relationship. So since diet and serum cholesterol have a zero correlation cross-sectionally, an observational study of the relationship between diet and coronary heart disease incidence will suffer from the same difficulties. So again, if you do the math, observational studies would unavoidably show nearly no correlation between saturated fat and heart disease. These prospective studies can be valuable for other diseases, but the appropriate design demonstrating or refuting the role of diet and coronary heart disease is a dietary change experiment.

And those dietary change experiments have been done; they implicate saturated fat, hence the lower saturated guidelines from basically every major medical authority. In fact, if we lower saturated fat enough, we may be able to reverse heart disease, opening up arteries without drugs or surgery. So with this knowledge, how would the meat and dairy industry prove otherwise? They use the observational studies that mathematically would be unable to show any correlation.

All they need now is a friendly researcher, such as Ronald M. Krauss, who has been funded by the National Dairy Council since 1989, also the National Cattleman's Beef Association, as well as the Atkins Foundation. Then they just combine all the observational studies that don't have the power to provide significant evidence, and not surprisingly, as published in their 2010 meta-analysis, no significant evidence was found.

The 2010 meta-analysis was basically just repackaged for 2014, using the same and similar studies. As the Chair of Harvard's nutrition department put it, their conclusions regarding the type of fat being unimportant are seriously misleading and should be disregarded, going as far as suggesting the paper be retracted, even after the authors corrected a half dozen different errors.

It's not as though they falsified or fabricated data--they didn't have to. They knew beforehand the limitations of observational studies, they knew they'd get the "right" result and so they published it, helping to "neutralize the negative impact of milk and meat fat by regulators and medical professionals." And it's working, according to the dairy industry, as perceptions about saturated fat in the scientific community are changing. They even go so far to say this is a welcome message to consumers, who may be tired of hearing what they shouldn't eat. They don't need to convince consumers, just confuse them. Confusion can easily be misused by the food industry to promote their interests.

It's like that infamous tobacco industry memo that read, "Doubt is our product since it's the best means of competing with the body of fact that exist in the mind of the general public." They don't have to convince the public that smoking is healthy to get people to keep consuming their products. They just need to establish a controversy. Conflicting messages in nutrition cause people to become so frustrated and confused they may just throw their hands up in the air and eat whatever is put in front of them, which is exactly what saturated fat suppliers want, but at what cost to the public's health?

If that "Doubt is our product" memo sounded familiar, I also featured it in my Food Industry Funded Research Bias video. More on how industries can design deceptive studies in BOLD Indeed: Beef Lowers Cholesterol? and How the Egg Board Designs Misleading Studies.

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Image Credit: Taryn / Flickr

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The Saturated Fat Studies: Buttering Up the Public

NF-Sept29 The Saturated Fat Studies Buttering Up the Public.jpeg

Time magazine's cover exhorting people to eat butter could be viewed as a desperate attempt to revive dwindling print sales, but they claimed to be reporting on real science--a systematic review and meta-analysis published in a prestigious journal that concluded that current evidence does not clearly support cardiovascular guidelines that encourage cutting down on saturated fat, like the kind found in meat and dairy products like butter.

No wonder it got so much press, since reducing saturated fat intake is a major focus of most dietary recommendations worldwide, aiming to prevent chronic diseases including coronary heart disease. So, to quote the Center for Science in the Public Interest, "What gives? Evidently, shaky science...and a mission by the global dairy industry to boost sales."

They interviewed an academic insider, who noted that some researchers are intent on showing saturated fat does not cause heart disease, which can be seen in my video The Saturated Fat Studies: Buttering Up the Public. In 2008, the global dairy industry held a meeting where they decided that one of their main priorities was to "neutralize the negative impact of milk fat by regulators and medical professionals." And when they want to do something, they get it done. So they set up a major, well-funded campaign to come up with proof that saturated fat does not cause heart disease. They assembled scientists who were sympathetic to the dairy industry, provided them with funding, encouraged them to put out statements on milk fat and heart disease, and arranged to have them speak at scientific meetings. And the scientific publications we've seen emerging since the Mexico meeting have done just what they set out to do.

During this meeting, the dairy industry discussed what is the key barrier to increasing worldwide demand for dairy. There's global warming issues and other milks competing out there, but number one on the list is the "Negative messages and intense pressure to reduce saturated fats by governments and non- governmental organizations." In short, the negative messages are outweighing the positive, so indeed, their number one priority is to neutralize the negative image of milk fat among regulators and health professionals as related to heart disease.

So if we are the dairy industry, how are we going to do it? Imagine we work for Big Butter. We've got quite the challenge ahead of us. If we look at recommendations from around the globe, there is a global scientific consensus to limit saturated fat intake with most authoritative bodies recommending getting saturated fat at least under 10% of calories, with the prestigious U.S. Institute of Medicine and the European Food Safety Authority recommending to push saturated fat consumption down as low as possible.

The latest guidelines from the American Heart Association and the American College of Cardiology recommend reducing trans fat intake, giving it their strongest A-grade level of evidence. And they say the same same for reducing saturated fat intake. Since saturated and trans fats are found in the same place, meat and dairy, cutting down on foods with saturated fat will have the additional benefit of lowering trans fat intake. They recommend pushing saturated fat intake down to 5 or 6%. People don't realize how small that is. One KFC chicken breast could take us over the top. Or, two pats of butter and two cubes of cheese and we're done for the day--no more dairy, meat, or eggs. That'd be about 200 calories, so they are in effect saying 90% of our diet should be free of saturated fat-containing foods. That's like the American Heart Association saying, "two meals a week can be packed with meat, dairy, and junk, but the entire rest of the week should be unprocessed plant-foods." That's how stringent the new recommendations are.

So this poses a problem for Big Cheese and Chicken. The top contributors of cholesterol-raising saturated fat is cheese, ice cream, chicken, non-ice cream desserts like cake and pie, and then pork. So what are these industries to do? See The Saturated Fat Studies: Set Up to Fail.

For those unfamiliar with Trans Fat in Meat and Dairy (and refined vegetable oils), that's why I made a video about it.

The U.S. National Academy of Sciences Institute of Medicine "as low as possible" position, echoed by the European Food Safety Authority, is described in my video: Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero.

What happened when a country tried to put the lower saturated fat guidance into practice? See the remarkable results in Dietary Guidelines: From Dairies to Berries.

Don't think the dietary guidelines process could be undermined by underhanded corporate tactics? Sad but true:

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Image Credit: Johnathan Nightingale / Flickr

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