Every time you hop on the internet, it seems there is conflicting nutrition advice coming from every direction. Bacon is good for you one day, then it causes cancer the next. One of the best examples in recent years is saturated fat.
Time Magazine put butter on their cover, insisting that everything we claim to know about saturated fat is wrong. But what does the science say? What’s the deal with saturated fat?
First off, what is saturated fat? It’s a chain of monoglycerides and fatty acids that are “saturated” with hydrogen atoms. And what I mean by saturated, I mean saturated as in, combined, holding, soaked. So, the hydrogen atoms are covered all over a chain of fatty acids and monoglycerides.
This makes saturated fats solid at room temperature (think bacon grease in a can after you let it cool down). Most of the saturated fat in the western diet comes from animal products like butter, cheese, milk, and meats.
We’ve known for over 50 years that as dietary saturated fat intake rises, so does your cholesterol, especially the bad kind. In fact, this relationship is so consistent and reproducible that you can accurately predict the total rise in serum cholesterol based on the amount of saturated fat someone consumers using the Hegsted Equation.
The Hegsted Equation was created to predict how much cholesterol will go up based on how much-saturated fat you have them eat. So if you want your LDL cholesterol to go up 50 points all you have to do is eat like 30% of your calories from saturated fat. When you plug in the numbers, the change in cholesterol shoots up, right as predicted.
These results were found through hundreds of metabolic ward studies, where people are locked in a room for weeks with researchers who have total control over their nutritional intake. That’s as accurate as nutrition studies get.
We also know that high total serum cholesterol is the primary risk factor for cardiovascular disease, our number one killer. Randomized controlled clinical trials, the gold standard of study design, have shown over and over that, a reduction in saturated fat intake not only drastically lowers serum cholesterol but that it also reduces the risk of cardiac events like heart attacks. The most prestigious, governing scientific and public health bodies in the world are unanimously in favor of reducing or eliminating dietary saturated fat intake because of its clear role in the development of atherosclerotic disease.
So if there’s such a consensus in the scientific community, why are we still having this debate?
The primary reason is that the meat and dairy industries (and the Atkins Foundation) have done a masterful job of paying scientists (like Ronald M Krauss) to conduct meta analyses of cross-sectional studies which do not have the “power,” in statistical terms, to demonstrate statistically significant correlations between saturated fat intake and heart disease.
This happens because cross-sectional studies, as opposed to controlled feeding experiments, are only designed to show a change in cholesterol based on dietary interventions. Knowing the change in someone’s cholesterol after altering their diet, without knowing their total cholesterol level, makes it impossible to infer a relationship between that change and disease risk.
There are very clear relationships between total cholesterol levels and the manifestation of coronary artery disease, so much so that we can say with scientific accuracy that people with a total cholesterol under 150 (such as you might find in Sub-Saharan Africa) will be virtually disease free. We can also predictably reverse coronary disease by getting saturated fat low enough.
There is nothing academically dishonest about doing cross-sectional studies of this kind; they show other relationships that are important. The problem is in the funding and publication of reviews that selectively and exclusively use this limited data. The studies are set up to fail. This is the sole intention of the industry: confuse the public and remove their incentive to change by manufacturing doubt. That was, after all, the MO of the tobacco industry in decades past.
Articles like the one in TIME and other major media outlets continue to stoke the fire of controversy and create mass appeal for leaders in the high fat/low carb world, who cash in on their contrarian point of view to the detriment of public health. We might laugh if the stakes weren’t so high.
Isn’t it time we looked critically at the evidence and stopped killing ourselves with food? The beautiful thing about science is that it’s true, whether you believe it or not.