In short, bold policies have been based on fragile science, and the long term results may be terrible.
Do you think this sentence explains why nearly everything we think about food is wrong? I recently came across this article and I have strong disagreement with its contents.
The BMJ feature opinion piece authored by Richard Smith, Are some diets “mass murder”? and Nina Teicholz’s book, The Big Fat Surprise, both read more like conspiracy theories than scientific analyses. The confusion does work great for industry and media though, and people love hearing good news about their bad habits.
Of course there are problems with nutritional science; studying humans is damn difficult. But we gather knowledge from multiple disciplines. Major problems arise when reductionist science comes into play, and this creates great opportunity for fad diets and controversies that are based on false premises. Correlative studies are ineffective for drawing conclusions, hence why they’re used only to initiate further research rather than create dietary guidelines.
Smith writes, “Our bias against saturated fat remains firmly in place today.” Bias against saturated fat? Are you kidding me? How could there possibly be a bias against saturated fat? Smith states that there’s some form of “hypothesis that saturated fat is the cause of cardiovascular disease” floating around influencing dietary practices, but that’s complete nonsense. You’re not going to hear any reputable scientist say this, only the media says this. This wasn’t even Keys‘ theory (the man who is credited, justly or not, to first propose a link between saturated fat and heart disease). Saturated fat can be a contributer to cardiovascular disease, and we know through biochemistry how it is so, but there are many factors involved with the disease. Denying this is complete absurdity.
Honestly, it sounds very akin to creationists attacking Darwin and evolutionary theory without actually having any understanding of what theory he proposed and the current mainstream scientific understanding of evolution. Keys is unjustly attacked and misrepresented in a lot of fad diet books and media (most of which are authored by journalists rather than scientists or nutritionists). Too bad fad diet books, including The Big Fat Surprise, start off with a completely incorrect representation of Keys’ work. It all goes downhill from there.
What about the whole “low fat” movement and associated products on the market? “Low fat” products usually entails higher sugar content, thereby decreasing the proportion of fat rather than decreasing total fat. Fat intake hasn’t gone down for Americans despite dietary guidelines, but many Americans believe they are eating less fat when in reality they’re simply eating more calories. There are two huge players in food industry — sugar and meat. Both point fingers at each other and this results in a merry go round of misinformation. They may have influence over policies but science has less bias (though industry does sponsor much research).
The Standard American Diet contains significant amounts of refined carbohydrates (predominantly in the form of sugar) and fat (predominantly in the form of refined oils and animal products). Americans are nowhere near following a low fat diet as is recommended by many authoritative health boards across the world, but many Americans think they’re eating low fat because that’s what industry tells them. This in turn has lead to recent fears for carbohydrate as fad diets like Atkins and more recently Paleo have appeared demonizing carbohydrates and associating carbs to the obesity epidemic.
Fat intake has not decreased in any form. Calorie intake has increased. Americans are eating more fat than ever before on top of more sugar. Consequently, Americans are facing an obesity epidemic like never before. There’s more to the picture than this (the combination of refined carbs and refined fat in tandem promote additional weight gain), and media greatly oversimplifies.
Here is some more information from registered dietitian, Jeff Novick:
Around the turn of the century, Americans were using butter, lard, schmaltz (chicken fat) and other rendered animal fats as an ingredient in food and as a cooking medium … at the time, no one realized the negative impact of saturated fats on our health. The percentage of fat in the American diet stayed fairly consisted from 1900 to 1960.
The historical event that lead to the change in the 60’s was the 1961 AHA Central Advisory Statement that advised Americans to replace their saturated fat intake with polyunsaturated fats.
The best way to do this would have been to swap out foods rich in saturated fat, with foods rich in PUFAs. Instead of a breakfast of bacon and eggs, exchange it for one of oatmeal and fruit. Instead of saturated fats like butter and lard, exchange it for a liquid oil that was higher in PUFA’s like soy oil, etc. By exchange, they meant on an equal calorie basis without increasing total calories.
Unfortunately, this is not what happened. No one wanted to change the food they were eating and no one wanted to use liquid PUFA’s as they do not work as well in the food supply as saturated fats … However, if you partially hydrogenated them and made these liquid oils into margarine and shortening, these chemically altered fats then had the same beneficial characteristics of saturated fats. Therefore, increasing amounts of them ended up in the food supply but not on an equal calorie basis. Instead, we saw one the largest increases in calories, driven mostly by added fats since 1960.
So, some of the saturated fat was replaced with shortening, margarine and other partially hydrogenated oils. As a result, trans fats intake went way up while saturated fat intake barely nudged down and total fat intake and calorie intakes shot up. That was not the intent of the 1961 AHA statement at all or the 1977 Senate Subcommittee hearings on Diet and Health or the 1980 Dietary Guidelines. What they did not realize at the time, was the way their recommendation would be interpreted and applied by the commercial food industry, thus releasing a ticking time-bomb into the food supply called trans-fat.
Compare saturated fat intake and fiber intake. Fiber intake is associated with good health. Why? Because if your diet is high in fiber it generally entails that you’re eating high amounts of healthful fruits, vegetables, whole grains, legumes, nuts and seeds with minimal animal products since animal products are void of fiber. It’s also because fiber has been shown through numerous studies to have beneficial effects in isolation, but not as much benefit in isolation as an overall healthful diet. Reductionist science has its limitations with this correlation.
Saturated fat intake is associated with poor health. Why? Because if your diet is high in saturated fat it generally entails that you’re eating fewer amounts of healthful fruits, vegetables, whole grains, legumes, nuts and seeds and lots of animal products since animal products are high in saturated fat. It’s also because saturated fat has been shown through numerous studies to have detrimental effects in isolation, but what’s worse is the absence of health promoting foods. Again, reductionist science has its limitations with this correlation.
Correlation shows: fiber is good, saturated fat is bad. What to do? What if you’re an average American and decide to supplement fiber and add more PUFAs to your diet without actually improving your overall diet? You’ll still be at high risk for cardiovascular disease and in poor health, you may have even made things worse!
Correlations aren’t causation, and correlative studies can show different results depending on the type of analyses. Correlative studies are what the media tends to focus on the most as it leads to the most amount of controversy.
Saturated fat intake is a marker for cardiovascular disease, it can also be a contributor, but it isn’t a cause in of itself and it probably isn’t the main factor — cardiovascular disease is more complex than that and there are so many problems with the American diet it’s impossible to pinpoint exactly one culprit.