You don't need to be an authority to see how the majority of human nutrition science is barely a step above junk. Pick any journal in the field and go through the last few issues. You'll mostly find observational studies with subject reported data (known to be inaccurate). Very few long, term randomized controlled trials with meaningful endpoints.
There have been tons of nutritional experiments which are extremely rigorous.
Unfortunately, like most fields it’s the junk you read about because rigor is slow/difficult/expensive and therefore less common than BS. Just look at say fusion research and all it’s seriously flawed experiments.
That's just not true. We know a lot about the basics of nutrition. Actual nutrition scientists mostly agree on lots of different things.
The problem is that the public doesn't want to hear it, so the media keeps running articles that make it simple like "nobody knows anything". Which is just plain false.
Care to list some of the basic tenants of nutrition that are widely agreed upon?
About the only things I see as generally accepted are to eat a varied diet (whatever that means), keep total consumed caloric content near the amount expended, eat at least the RDA of micronutrients, and drink enough water to avoid overt dehydration.
I'm not a nutrition scientist, so obviously not at all an expert that can probably chime in with some more findings.
But generally - yes, afaik there's mostly a consensus that total caloric intake is the driver of amount of adiposity, that maintaining a 10%-20% body fat percentage (for men) is optimal for long term health, that most diets are close from a health and fat-loss perspective - meaning, amount of adiposity is the main driver of long-term bad health, especially as compared to individual ingredients. There are some things that are known to be specifically problematic, e.g. trans-fats, at any amounts. And there are healthier and less healthy foods, some of which we know - but total caloric intake is the only driver of body composition, and a bigger driver of body health.
Most of this is basic - probably because, as I said, I'm not a nutrition scientist myself so only understand the basics myself.
That said, a large part of the population doesn't even understand these basics either, preferring to constantly talk about and argue about specific diets, keto vs. vegan vs. whatever. And science mostly has that question covered, as far as we can tell right now.
For a more in-depth take on this from someone who actually is an expert, I recommend videos by Mike Israetel:
At a practical level nutrition isn’t generally a problem, but that says more about the human body / food than the lack of scientific knowledge.
There is a long list of things that cannot be synthesized by people and must be consumed. (Elements like Potassium as well as specific nutrients like Vitamin C and Thiamine being well known.) There’s a longer list of things than can be synthesized but should largely be consumed ex:
Linoleic acid (LA), an omega-6 fatty acid, and α-linolenic acid (ALA), an omega-3 fatty acid, are considered essential fatty acids because they cannot be synthesized by humans.
The long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), can be synthesized from ALA, but due to low conversion efficiency, it is recommended to consume foods rich in EPA and DHA.
There’s also a lot of basic facts that get complicated when you dig into them. For example calories produced by burning foods isn’t 1:1 with the calories available to people. Cellulose for example burns but is effectively indigestible. One way to investigate this is to have some eat something and then burn their poop, followed by many studies that do so for various reasons.
There’s also a lot of nutrition science that straddles the line with medicine. Thus there exists many specialized diets for various conditions etc.
Snake-oil and moralizing. Dietetics suffers from the same issue that mental health does: there's an underlying stigma that causes people to inflict a moral judgement on the ill; fat people - or so the old line of thinking goes - are immoral. A shocking number of people, including many doctors and scientists, view diabetes as a "fat people disease," and that diabetics are in effect being punished for their gluttony. This isn't always a conscious bias, but it has very negative effects.
It reminds me of the studies they've done in Canada and the US about how natives (American Indians) die a lot of the time in the ER because they're immediately written off as alcoholics or drug-addicts, and so their complaints are evaluated through the lens of "this person just wants opiates."
People generally consider, although this is not universally agreed, that math isn't science. To me the distinction matters, although it's fairly subtle.
This is underscored by frequently cited articles, like: "The Unreasonable Effectiveness of Mathematics in the Natural Sciences", in which math is treated as separate, but intimately related, to natural philosophy.
I think you can do math without science, but you can't do science without math.
