[nradov]

Even the peer-reviewed research is mostly junk observational studies that are distorted by the healthy subject effect and other uncontrolled variables. That is not a sound basis for making personal dietary decisions.

A better approach for most people is to conduct personal n=1 experiments and just see empirically what works best for you in terms of subjective feelings and objective performance metrics.

[soldehierro]

This is unfortunately the status quo of nutrition research; A long-term RCT is the "gold standard", but it is exceedingly difficult to recruit subjects and ensure their compliance over meaningful periods of time. Which is part of why constant flip-flopping about whether something is healthy or not is almost a trope in journalism. Nonetheless, a few principles have been well established: vegetables are good, fruit is (mostly) good, refined grains and free sugars are bad.

The issue with personal experiments is often that they are just as biased and cannot be conducted over meaningful time-scales. As an anecdote to illustrate this, I am significantly more productive and energetic when consuming a single sugary, chocolately coffee, but it would be foolish to conclude over such a short period of time that my personally ideal diet should include sugary coffee. I'm not deluded that this is a healthy practice, however; free sugars, fructose in particular, are demonstrably a major factor in the pathogenesis of lifestyle-related diseases.

[toyg]

> vegetables are good, fruit is (mostly) good, refined grains and free sugars are bad

Even those are not really absolutes, because a diet with only those "good" elements will still be worse than a mix including animal proteins. Also, some vegetables are simply bad in excessive quantities (mushrooms, potatoes, etc).

The problem we typically have is just over-abundance of everything in our diets. Too much meat is bad, too much vegetables are bad, too much fruit is bad, too much fish is bad, too much dairy is bad. And that's because our bodies evolved to make the most of anything they could digest, since the normal state was scarcity and every little bit helped with survival. Now these finely-tuned "recycling systems" are routinely oversupplied in ways they were not meant to be, and they can't help themselves but overproduce nutrients of all sorts, with all sorts of unpredictable results.

We are like ports where ships continue to unload containers at excessive rates. Some of those containers will end up polluting the area, some will just accumulate into horrible mountains, the motorways will be clogged by a continuous stream of lorries, etc etc etc. Some of those boxes will contain life-saving medicines and some will contain pointless junk, but that's not the actual problem - if you reduce the rate of shipping, then all containers will happily go where they have to go and be dealt with as they "deserve".

We were probably not built to have three meals every day.