“We found a link between cabbage and innie bellybuttons, but that doesn’t mean it’s real.”
“Our foray into nutrition science demonstrated that studies examining how foods influence health are inherently fraught. To show you why, we’re going to take you behind the scenes to see how these studies are done. The first thing you need to know is that nutrition researchers are studying an incredibly difficult problem, because, short of locking people in a room and carefully measuring out all their meals, it’s hard to know exactly what people eat. So nearly all nutrition studies rely on measures of food consumption that require people to remember and report what they ate. The most common of these are food diaries, recall surveys and the food frequency questionnaire, or FFQ.”
http://fivethirtyeight.com/features/you-cant-trust-what-you-read-about-nutrition/
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