Here's Why Nutrition Science Is Always Contradicting Itself

Follow food research long enough and you'll start to feel insane. At least that's how I feel, and that seems to be how medical journalist Clare Wilson feels, too. Her recent piece in the South China Morning Post magazine called "Food science: should we believe anything we read about nutrition?" dissects the methodology of nutritional research and how the media picks and chooses food-related stories to publish. It'll either make you question everything or, if you're like me, affirm your long-held belief that new/terrifying research on heretofore healthy foods should be mostly ignored. We highly recommend the read.

Wilson opens with eggs, the perfect example of our collective seesaw in popular food science. Eggs were always a breakfast staple until the 1960s, when we discovered that cholesterol is bad for us. Eggs are therefore bad; R.I.P. eggs. Then, in the '80s, we found out that cholesterol in food doesn't really affect our heart health. Eggs are back on—hooray for eggs! But wait, no. In 2019, more research arose that found the cholesterol in eggs is, once again, ravaging our bodies.

According to Wilson, there are tons of problems in diet research, one of which is that it's pretty much impossible to have a control group. Nutritionists can't ask people to change their diet for years on end (or know that these participants have stuck to it). So instead, they have subjects complete food diaries and try to draw conclusions from that. But there are so many other factors—class and income level being huge ones—that impact our health beyond what we eat. Money and diet are so intertwined that it's difficult for researchers to tease them apart. "For example," Wilson writes, "even if blueberries do not affect heart attack rates, those who eat more of them will have fewer heart attacks, simply because eating blueberries is a badge of middle-class prosperity."

Another big factor is publication bias. Food journalists (like myself) are so much more interested in studies that find a link between two things. "Hot sauce gives you cancer" is a more gripping headline than, say, "Diet is a complicated thing that mostly has to do with privilege and access but maybe try to eat balanced meals." Even within the research community itself, similar biases exist. There have been so many studies at this point that anyone can just cherry-pick whichever studies fit their theories. Plus, virtually no diet studies can apply to a person's entire life. It's an imperfect system, to say the least.

Anyway, I'm blathering, but please read this piece, then go ahead and enjoy some delicious, cholesterol-ridden eggs.