Pure gassy speculation here: Once we account for the initial transition (be it palatability, convenience, fermentability, or what have you), the reasons for the continuation of the new way of eating, despite losses in individual health, ought to be considered.

I've thought for some time now that there may be a powerful instinct in humans (and possibly other omnivorous animals) to carefully watch what other members of the species eat, and to copy that behavior pretty rigidly. My reasoning is this: Because we are generalist plant eaters (as opposed to specific plant eaters, like koala bears/eucalyptus leaves), we must exercise caution in trying new vegetation. Meat is usually pretty safe, once caught, and fruits nearly as safe, but other plant parts--especially from non-cultivated plants--come packed with an arsenal of chemical weapons to discourage predation. So if you're going to feast from the green buffet, you've got to make sure you don't eat the wrong carroty-looking thing (like the one with the purple spots). From evolution's "perspective," an efficient way to do that is to wire in an instinct to eat what other living and apparently healthy members of the species are eating, and not venture much beyond that.

Such an instinct could exhibit some variability in individuals, with most being somewhat shy around new foods, and some being bold renegades (not too many of those, though -- as the saying goes among mushroom hunters, "There are old mushroom pickers, and there are bold mushroom pickers, but there are no old, bold mushroom pickers."). And there could be a concomitant instinct to tell others how to eat, too -- this would help limit (presumably) the number of deaths from, say, hemlock poisoning.

As I said, pure gassy speculation, but would explain a number of observations about human culture and foodways, and the near-religious fervor people seem to feel about the way they eat (and I don't exempt myself from those observations).

Convenience, price, availability, storability. Manufactured food can be fine-tuned to greatly appeal to our senses.

Add to that "Status symbol." Those in developing countries who can afford to eat processed foods are typically wealthier.

I think savings of time is the major reason. As you pointed out recently (if memory serves), food acquisition and preparation ran ~40 hours per week for most hunter-gatherers. You can get similar calories in a few hours from a supermarket.

All of the above.

You can just imagine the scene. People who have more advanced technology descend on your isolated corner of the world. They introduce their food to you.

You can't help being a little impressed by them. Their food is the food of the future. You spend an hour making breakfast and they show you something that takes 5 minutes to prepare. And it's sweet!

Would you say no?

"The leading branded ultra-processed foods and drinks are manufactured by transnational companies most able to purchase substrates for their products at rock-bottom or even subsidised prices. They penetrate new markets in lower-income countries, with massive marketing and advertising budgets, and may undercut local industries, drive them out of business, or take them over.

In the last decades, ultra-processed products have usually become relatively or even absolutely cheaper to manufacture, and sometimes – not always – relatively cheaper to buy. They are often manufactured in increasingly supersized packages and portions at discounted prices with no loss to the manufacturer. The packaging may cost more than the contents."

from The Big Issue is Ultra-Processing

This is a rather detailed and fascinating essay I found via Marion Nestle's blog, a while back. If you haven't read Nestle's book "Food Politics," well, what are you waiting for?

Hyperpalatibility, sugar and it's damn easy, no effort required.

We are wired to like all three.

I don't really buy the hyperpalatibility argument because most of the developing countries I've lived in (predominantly in Africa) have very different taste than Western tastes. Sugar as not made the tremendous in-roads here that it has elsewhere, except in the form of soda.

Convenience is huge. Most staple foods in Africa take a LONG time to hand-process and cook. Rice takes 15 minutes, tops. And the Chinese are flooding African markets with Chinese rice as low as half the price of locally grown rice. More and more women are working outside the home and find it easier and quicker to use convenience foods.

Another reason is the same thing that happened in America. When I was a kid, things like ice cream or soda were "treats" for "special occasions", now they are everyday. Same thing is happening in Africa. More availability, heavy-duty marketing, higher incomes all give people the opportunity to eat special foods all the time.

The other thing is -- they are no different than us and just as Americans did not understand what their diet was doing to their health, neither do most people in "traditional" cultures or however you want to put it. Add to that a growing portion of the population who are desk-jockeys and have the chance to drive cars or take taxis, a culture that considers being "fat" a sign of health and wealth, and a very "here and now" perspective on life that doesn't easily make connections between something I am doing now and having diabetes in 10 years and voila!

I came across this article a couple hrs ago and was actually wondering if you'd seen it Melissa- http://www.montrealgazette.com/business/Diet+crisis+develops+among+Inuit+people/5336804/story.html

Probably not really anything new there, but I thought it was lame they didn't go into detail as to what is in the traditional Inuit diet, but made sure to point out the modern Inuit are lacking in "fruits, vegetables, grains and dairy."

I second the above points about convenience, storability, etc.

Wild guess here, but I think food security is a big part of it. Harvest grains can be dried and stored for long periods without spoilage.

My other guess is fermentability. People in general love beer.

Superstimuli, convenience, etc.