> Notwithstanding the "fat-free everything" fad, the best epidermiological data we have so far suggest that fat consumption is highly correlated with coronary heart disease and all sorts of late-life complications. This could be wrong or out-dated, but FDA is only acting on the mainsteam scientific opinion that fat should be limited in a typical diet

Yet if we look at other peoples and cultures around the world we can find several with high fat diets without the coronary heart disease and other problems that seem to plague high fat consuming Americans. Some examples are the natives of many South Pacific islands, the Inuits, and the Maasai.

Components of a diet do not act in isolation. It really has to be looked at as a complete system. If reducing fat in the American diet reduces coronary heart disease, that does not mean fat is bad or fat is causing coronary heart disease. It could be that if some one component instead of fat were removed the same reduction in coronary heart disease might occur (carbohydrates might be a good candidate, since the traditional high fat Inuit diet was very low in them, and they have much lower coronary heart disease than mainstream Americans do).

For nearly every rule, supposedly backed by the then current science when the rule was published, it is usually possible to find some place where the traditional diet breaks that rule yet the people there are doing fine, not suffering from the afflictions we've been told will befall is if we violate the rule.

The tendency to look at things in isolation doesn't just show up in unjustly declaring particular things bad. It also sometimes declares things good without sufficient justification. People look at, say, traditional Mediterranean diets and see that they have good outcomes, and figure it must be due to their heavy use of, say, olive oil. So then they start slathering olive oil over everything and expect they are going to get healthy no matter how crappy the stuff they are drowning in olive oil. In reality, there is probably no magic ingredient in the Mediterranean diets...it is the totality of their diet that is good.

What should be a simple task--regularly eating in a healthy way--is ridiculously complicated and requires way more research than it should in the US. And that's without getting into processed foods, and how the goals of processed food providers don't necessarily align with the goals of those trying to eat healthy.

I read somewhere (don't remember where, so can't give a good cite) that biochemists say we only understand about 10% of the chemical processes in our bodies. We know some things various nutrients are used for, but there are many we don't know. We often don't understand exactly how particular nutrients go from being part of our food to being being available at the places they are used in a form usable to our cells.

So it looks like the only reasonably effective way to eat healthy is to find some group of people whose traditional diet is known, and who have or had good outcomes in the health areas you are interested in, and had those good outcomes for a long time, and eat like you are one of them.

What I've not seen discussed is whether or not you can mix different diets this way. For instance, if you like the outcomes of traditional Mediterranean culture diets, and the outcome of traditional South Pacific Island diets, and so on for several cultures and their traditional diets, should you expect good outcomes if one day you eat like a South Pacific islander, and the next day like someone from a Mediterranean culture, and so on? Or do you need to stick with each culture's diet for some kind of extended period?