alt Hacker NewsDoes this actually pose an issue for most studies?
This seems like it would be an issue for any studies relying on absolute food consumption being accurate. Most studies I come across frame their findings in relative terms (likely for this very reason): Individuals who engage in more of X compared to their peers show a correlation with outcome Y.
For example, if you’re trying to determine whether morning coffee consumption correlates with longevity it doesn’t seem particularly relevant if you believe everyone is underreporting their food intake, as the article implies; it's a relative comparison.
Sure, those findings often get twisted into clickbait headlines like “X is the secret to a longer life!” but that’s more a popular science problem than an issue with dietary research itself.
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All of those headlines are based on meta-studies putting together 100 junk studies, based on bad data, which then informs actual medicine and health trends and American X Association and...
For your specific example - "morning coffee" could be anything from plain espresso shot to full 600+ calorie starbucks "coffee" but the meta-study-machine will lump them together.
It's kind of like feeding all of reddit's comments into chatgpt, asking it about stuff, and trusting its answers at a society-level with your health on the line.
> This seems like it would be an issue for any studies relying on absolute food consumption being accurate.
Exactly. Those studies either don't get done, or when they're done, they produce garbage results that get ignored or get interpreted as diminishing the importance of absolute food consumption.
> it doesn’t seem particularly relevant if you believe everyone is underreporting their food intake
It says that virtually everyone underreports. It doesn't say that everyone underreports equally, and there are good reasons to expect this not to be the case. If embarrassment is a contributing factor, for example, you would expect people who are more embarrassed about how they eat to underreport more. If people remember meals better than they remember snacks, people who snack more will underreport more than people who snack less. If additional helpings are easier to forget than initial helpings, people will underreport moreish foods more than they underreport foods that are harder to binge on. With so many likely systematic distortions, it would be surprising if everyone underreported equally.
But finding correlations is only the first and easiest step in determining causation. And almost nobody continues with the hard work that follows. So we have tons of studies showing correlations one way or the other, and tons of conflicting studies. And we are apparently satisfied with this. The state of nutrition research is abysmal.
most people are embarrassed about the truth. So they will over report vegetables while not mentioning how much alcohol or tobacco they had (or illegal drugs which the study probably legally must report to the police). Or a self proclaimed vegetarian will not report meat they ate despite their claim. fat people will report they skipped desert.
You are assuming that the underreporting will be uniform. In reality people may be underrporting things they are embarrassed about and maybe even overreporting the opposite.
This is a flaw in the data that is much harder to account for.