If you grew up anywhere near a TV, you'll probably remember this:
Popeye, so the story goes in pretty much every episode of his cartoon, gets strong when he eats his spinach. And the spinach is good for you, as your mother probably told you, because it's the vegetable with the highest iron content. Except that it isn't.
As explained by Samuel Arbesman in his book The Half-life of Facts: Why Everything We Know Has an Expiration Date, the iron content of spinach was misunderstood for decades thanks to a recording error by a German scientist. Spinach contains about 3.5mg of iron per 100mg serving, but the scientist mistakenly recorded it as 35mg. As Arbesman points out, 35mg is a shocking amount of iron - the equivalent of eating a small paper clip. But that did not prevent the nutritional myth from lasting for decades and spawning a popular cartoon. Here is a list of the actual iron content of various foods put out by the National Institutes of Health.
The point here isn't to pick on spinach or Popeye, but to point out how wrong common knowledge about diet and nutrition can be. That's why its important to be vigilant and look into such things yourself. You might be surprised how incorrect other popularly accepted concepts are, or more importantly, how they might not apply to you.
Since nutrition is an important component of overall fitness, we will be discussing some of the more popular beliefs in the future, such as whether sodium raises your blood pressure, if skim milk really is worse than whole milk and exactly how many cups of water you really need to drink.
Note: Though we try to stay on top of the science, and we do love to eat, we are not licensed nutritionists.