Re:Ask HN: What do we know about nutrition?
by bluGill on Tuesday June 29, 2021 @10:15AM
(#27676055)
There are some facts, but not as many as most people think.
Many people have religious views with a nutrition component, and some will try latch onto any study that supports their view and push it while ignoring others that don't support it. Some will even go so far as to design a study to provide the results they want. Vegetarians are the most obvious example of this, but there are others.
Nutrition is hard to study even when you want to do the right thing. Most effects are small and so it takes a long time for anything to be measurable. People tend to be unable to stick to their assigned diet long enough for a controlled study to get real data. (the exceptions are confined to a hospital bed or prison cell - both of which add confounding factors that mean the study won't apply to normal people)
Attempts are made to work around the above with surveys. However people are bad at remembering what they ate yesterday, and tend to lie to make themselves seem "healthier" than they really are. As always when doing a survey it is hard to separate confounding factors - the big on in this case is people who smoke also eat what is considered a less healthy diet and so it is hard to figure if the diet is really less healthy, or just another bad effect of smoking.
That said, there is some good science out there. I don't know how to find it, but there are nutritionists who know statistics and are making real attempts to separate the above confounders to find a truth. They tend to not get a lot of press though: since most of what they discover is small effects it won't generate headlines, while someone who doesn't take care can easily cherry-pick something and extrapolate far beyond reason to claim another miracle diet that will add 10 years to your life (or something else that diet will never do)
Many people have religious views with a nutrition component, and some will try latch onto any study that supports their view and push it while ignoring others that don't support it. Some will even go so far as to design a study to provide the results they want. Vegetarians are the most obvious example of this, but there are others.
Nutrition is hard to study even when you want to do the right thing. Most effects are small and so it takes a long time for anything to be measurable. People tend to be unable to stick to their assigned diet long enough for a controlled study to get real data. (the exceptions are confined to a hospital bed or prison cell - both of which add confounding factors that mean the study won't apply to normal people)
Attempts are made to work around the above with surveys. However people are bad at remembering what they ate yesterday, and tend to lie to make themselves seem "healthier" than they really are. As always when doing a survey it is hard to separate confounding factors - the big on in this case is people who smoke also eat what is considered a less healthy diet and so it is hard to figure if the diet is really less healthy, or just another bad effect of smoking.
That said, there is some good science out there. I don't know how to find it, but there are nutritionists who know statistics and are making real attempts to separate the above confounders to find a truth. They tend to not get a lot of press though: since most of what they discover is small effects it won't generate headlines, while someone who doesn't take care can easily cherry-pick something and extrapolate far beyond reason to claim another miracle diet that will add 10 years to your life (or something else that diet will never do)