Well. no one could be blamed much for being reluctant to buy into any announcement of what's good and bad. Too much advice has changed, sometimes back and forth. And then there are the many "diets," plans that focus on a single notion and pretend to huge advantages that just don't materialize. High carb, low carb, paleo. That paleo one really pushes my buttons for its gross ignorance of human prehistory.
What to do? How to eat? I think rational, critical thinking offers something useful. Most of the infuriatingly variable advice addresses what not to eat. So, is there anything we shouldn't eat? Humans and other animals have an innate drive to try to eat what the body detects is lacking. We're not any more conscious of it than any animal that exhibits preferences according to needs.
Now, we are omnivores. We can survive, after at least some fashion, by living on such diverse things as grass seeds or insects or blood or lobster. And today, most of us have available just about anything edible. We have our pick of almost everything a human can eat. Can we trust to our animal nature to guide us to a diet that fits our needs?
I think we can, but first, we have to avoid frustrating that sense. Our brains run on sugar. Some amount of sugar is included as a proper food, just as bears seek out honey. But if we are moved to want some sugar, and we ingest instead something that pretends to be sugar but is not, it makes sense that there in an inevitable internal conflict. Hey. I ate "sugar," but my body says no, no sugar detected. Better eat more sweet. What's going on?
We need fats. They're essential. Okay. So I'm eating something that looks like it contains fats. It has the mouth feel. It has the right look. I should be taking in desirable fat. But, no. It's a fake, and the body knows it and demands you try harder, because, "By gum, you're surrounded by "fat" foods, so why aren't I detecting fats when you eat them? Eat more now."
If we artificially restrict key food components, the body is not going believe we're eating enough and will demand more.
I submit that we have enough trouble without taunting the body's food sense. Evolution takes time, and we're still programmed to take advantage of times of plenty. We will eat as if there's famine around the corner, because that was a reality for much of our past. We'll try to eat of enough of what's available, trying to get out of it the things that would have been abundant in something that's out of season. In the past, the glut would have been offset by a shortfall that was surely coming, sooner or later. We have to deal with that. We don't need the additional problem of adding to the craving by stuffing ourselves with fakes. We have more than enough to do to be thoughtful and restrained in the presence of such plenty. We don't need an additional drive to eat that we can't even recognize.
We can eat too much in response to our old drives. We shouldn't add to that a drive that arises out of depriving our body by eating a boatload of stuff that's nutritionally lacking.
You know, people have always, in the plentiful modern times, been able to scale the amount of food eaten to physical need. We could have eaten more in the 1950's. We weren't stuck with what we could get on the smaller dinner plate of that time. We could order more food than the standard plate lunch special. But we mostly didn't. Look at the photos. People who were no more active were lean. A 1950's circus fat man would be out of work today and wouldn't be consider more than a bit stout. Look them up for yourself.
I don't blame the larger plates and larger servings on the restaurants. I think we accepted them because, at about the time they began to appear, our food supply had begun responding to the advice about fat, sugar, salt, etc. We began fooling our tongues with fakes that didn't fool our bodies. It's quite possible that the deprivations that result from that advice drove the phenomenon of bigger servings. HungryMan dinners. Big Macs. Super-Size. And 20-ounce sodas.
I made a small test. I took no-fat artificially sweetened yogurt for breakfast and lunch for a while. Then I took full-fat yogurt, sugar sweetened. I found the full-fat with sugar was, predictably more satisfying. Further, it required far less of the full-fat to feel comfortable than with the no-fat. Proteins were about equal. And the effect continued into the evening. It affected how badly I wanted food at supper, how much I considered was enough. I think there's something to this. And the nice thing is that the real stuff tastes better.