But yes - all these guesses are the scientific facts as far as we know them. You can complain about nutritional science being absolutely immature and probably highly corrupt, but it's still the best we have, and people who follow it aren't sheep anymore than I am for believing that there are atoms just because I was told so.
If a science is corrupt, it can be worse than useless. Scientific 'authority' is potentially as dangerous as other types of authority, if it isn't based on the scientific method.
Many authors (Nassim Taleb, Michael Pollan) talk about using other measures as heuristics. Pollan says 'would your great-grandmother have recognized it as food?'.
Adopting that one rule beats most modern nutrition advice.
We don't have evidence physics is corrupt. That's why your belief about atoms is reasonable.
I haven't known my great-grandmother much, but my grandmother lives on a typical German diet of eating as many greasy potatoes and meat as you can get, and like a good grandmother, she loves cake. She is doing okay because she exercises a lot, but tbh, many people of her generation are fat and sick on the same diet - all from natural "slow food".
As far as recognising it as food goes, has there ever been scientific advice in favour of processed foods? This seems like an implicit strawman to me.
>> What evidence do you have that nutrition science is corrupt and not based on the scientific method?
The fact that conclusions resulting from 'nutrition science' often seem to contradict, or are found to be completely wrong every few years should be an indication. Today drinking coffee is bad, tomorrow it reduces your risk of getting cancer. Yesterday nuts were bad and will make you fat, today thay aren't that bad after all because the calories they contain mostly leave your body undigested. At one point in time eating eggs more than twice a week was considered bad for you because of the cholesterol they contain, but according to the latest studies they are a 'superfood', and the cholesterol they contain appears to have no relation to blood cholesterol.
The problem with 'nutrition science' (I have to put it between quotes it because I consider it more like religion than science) is that health effects resulting from diet almost exclusively manifest themselves after many many years. This makes it very hard to reliably measure them, not only because it involves tracking large groups of people over a long period of time, who need to stay on a consistent diet, should not move around to much because otherwise other factors around them could affect their health etc.
Research into nutrition health benefits suffers from the same limitations many other epidemiology research suffers. As it turns out, health is correlated to so many other things it is almost impossible to reliably relate health effects to causes. The difference between epidemiologists and 'nutrition scientists' is that the former group directly acknowledges the limitations of their population studies, while 'facts' about nutrition are usually presented as truth, and nobody seems to care to challenge them.
There are lots of other things. Nutritional advice on breakfast, for example, is not based on anything more substantial than correlational studies. It ignores the contradictory evidence of traditional eating patterns that avoided breakfast.
I could go on. We're told to eat a low cholesterol diet, for example, even though blood cholesterol is not directly affected by dietary cholesterol in most cases.
I don't have too many supporting links, hopefully someone else can fill the gap. But the cochrane review is a good source of reviews of the state of our evidence.
And many of those scientific facts are facts for only limited group of people, based on combination of various genetic, age/lifestyle related and environmental factors.
But yes - all these guesses are the scientific facts as far as we know them. You can complain about nutritional science being absolutely immature and probably highly corrupt, but it's still the best we have, and people who follow it aren't sheep anymore than I am for believing that there are atoms just because I was told so.