I was thinking about this today, and then I found this thread.
I've started to wonder about food combining. Not that I'm about to eat everything in isolation, but I can't imagine primitive people having killed an animal and then said to themselves, "You know what would go great with this elk? Some spinach. Let's wait 'til we find some of that and then eat."
It does seem like certain combinations aren't typically found in foods in their natural state. Specifically, fat and carbohydrate. You find fat and protein (animal flesh and dairy), and carbs and protein (beans), but I can't think of many (if any) fat/carb combinations. Not that should stop anybody from having a bowl of berries with coconut milk or real cream.
I've just been curious. I feel like this is why certain foods are so easy to go crazy on, a great example being ice cream. It hits that sweet/fat button. I've also heard it said that this is why commercial ketchup is easy to OD on - it hits all the tastes - sweet, salty, sour, savory. (Maybe not bitter, though.) I could eat sweet potatoes plain as day and they're delicious, but who doesn't know they taste even better with some butter or coconut oil? (And even better than that if you add some cinnamon.)
Is this just an extension of the hyperpalatability issue? That certain foods -- particularly SAD foods that are "inventions" rather than actual foods -- are especially easy to eat a TON of, and especially hard to resist because they hit the reward centers more than, say, broccoli and steak? I haven't been a big fan of the hyperpalatability stuff, but I think I'm seeing it in a new way.
I think this is why, for me, at least, certain foods really need to be off limits. I have no "off switch" when it comes to them. I can eat to satiety with most foods, but there are a few that throw satiety out the window. My stomach could be about to burst and I would still go back for more... With those foods, I've found it's easier to abstain entirely than to fool myself into thinking I'll "just have one piece." (Because it never stops there.)
Edited to add: I just realized that with full-fat dairy, there's fat & carbs. Not a ton of carbs, but some. And I also realize that a good meal is really, truly, one of life's pleasures and regardless of what our ancestors did, I'm not about to deny myself a nice rare steak, some greens, and a glass of red wine. (Possibly preceded by a salad with mixed greens, pear, walnuts, and gorgonzola. Drool.)