Why (almost) everything you know about food is wrong - Vox
There was a time, in the distant past, when studying nutrition was a relatively simple science.
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Today, our greatest health problems relate to overeating. People are consuming too many calories and too much low-quality food, bringing on chronic diseases like cancer, obesity, diabetes, and heart disease.
Unlike scurvy, these illnesses are much harder to get a handle on. They don't appear overnight; they develop over a lifetime. And fixing them isn't just a question of adding an occasional orange to someone's diet. It involves looking holistically at diets and other lifestyle behaviors, trying to tease out the risk factors that lead to illness.
Today's nutrition science has to be a lot more imprecise. It's filled with contradictory studies that are each rife with flaws and limitations. The messiness of this field is a big reason why nutrition advice can be confusing.
It's also part of why researchers can't seem to agree on whether tomatoes cause or protect against cancer, or whether alcohol is good for you or not, and so on, and why journalists so badly muck up reporting on food and health.
To get a sense for how difficult it is to study nutrition, I spoke to eight health researchers over the past several months. Here's what they told me.
1) It's not practical to run randomized trials for most big nutrition questions
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2) Instead, nutrition researchers have to rely on observational studies which are rife with uncertainty
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3) Another difficulty: Many nutrition studies rely on (wildly imprecise) food surveys
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4) More complications: People and food are diverse
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5) Conflict of interest is a huge problem in nutrition research
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6) Even with all those faults, nutrition science isn't futile
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-----> http://www.vox.com/2016/1/14/10760622/nutrition-science-complicated