Spam logic.

For our ancestors, natural was something quite nasty. Natural often tasted bad. Fresh meat was rank and tough, fresh fruits inedibly sour, fresh vegetables bitter. Natural was unreliable. Fresh milk soured; eggs went rotten. Everywhere seasons of plenty were followed by seasons of hunger. Natural was also usually indigestible. Grains, which supplied 50 to 90 percent of the calories in most societies, have to be threshed, ground, and cooked to make them edible.

So to make food tasty, safe, digestible, and healthy, our forebears bred, ground, soaked, leached, curdled, fermented, and cooked naturally occurring plants and animals until they were literally beaten into submission. They created sweet oranges and juicy apples and non-bitter legumes, happily abandoning their more natural but less tasty ancestors. They built granaries, dried their meat and their fruit, salted and smoked their fish, curdled and fermented their dairy products, and cheerfully used additives and preservatives — sugar, salt, oil, vinegar, lye — to make edible foodstuffs.

The original article is A Plea for Culinary Modernism: Why We should Love Fast, New, Processed Food by food historian Rachel Laudan who also says that "Eating fresh, natural food was regarded with suspicion verging on horror, something to which only the uncivilized, the poor and the starving resorted".

Her point might be summarized as that from a historical perspective what we call "slow food" is "fast food" and for good reason - it's better. If we drop the fuzzy nostalgic fantasies and judge food by more objective criteria we will do better. So, the fact that a given tomato is an heirloom variety is not necessarily a sensible recommendation for it. It depends on whether it is good and has other desirable agronomic characteristics.

This is something like a point that I have made about grass fed beef. It isn't sufficient that it be grass fed, it must be grass finished, that is, fully mature and well fattened in a timely manner so that it has the flavor, tenderness and healthful nutrients that are implied but not always supplied by grass fed beef. A related point about organic foods is relevant: they are not always or even often nutritionally superior or produced in environmentally benign ways.

It may be that consumers don't have the time, inclination or expertise to make informed food decisions and so have to rely on labels and the judgment of retailers. The best that we can do is to be skeptical of those labels and retailers and hold them to account when their errors are exposed as a method to improve them. Anything said by an activist or advocate should, of course, be heavily discounted or at least eyed with the "suspicion verging on horror" that people once had for fresh, natural food.