On the timescale of evolutionary history, paleo enthusiasts note, agriculture is a fad. Illustration by Mike Ellis.

The first day I put my family on a Paleolithic diet, I made my kids fried eggs and sausage for breakfast. If they were still hungry, I told them, they could help themselves to more sausage, but they were not allowed to grab a slice of bread, or toast an English muffin, or pour themselves a bowl of cereal. This represented a reversal of the usual strictures, and they were happy to oblige. It was like some weird, unexpected holiday—Passover in July.

The Paleolithic diet—“paleo,” for those in the know—represents a new, very old form of eating, one confined to the sorts of food available in pre-agricultural days. These foods, as it happens, were not many. According to Sarah Ballantyne, the author of “The Paleo Approach,” a paleo diet consists of “meats, fish, eggs, vegetables, fruits, nuts, and seeds.” According to John Durant, the author of “The Paleo Manifesto,” even seeds are suspect and should be avoided. (A genuinely Paleolithic diet, Durant concedes, probably ought to include human flesh; however, he does not advise this.)

The list of foods that are not paleo, meanwhile, is a great deal longer; it includes cereal grains like wheat, corn, and rice; pseudo-cereal grains like amaranth and quinoa; legumes, dairy products, most vegetable oils, sugar, and anything that contains corn syrup or artificial coloring or flavorings or preservatives, which is to say, just about everything a contemporary American consumes. Most days, my kids pack their own lunches, but since I had banned the standard ingredients, starting with the bread for peanut-butter-and-jelly sandwiches, I figured I was obligated to step in. I rolled up some turkey slices and arranged them in a plastic container with some cut-up avocados. Then I gave each kid a banana and some paleo “cookies” I had made using ground-up almonds. The cookies looked like little hamburgers and tasted like sawdust.

There are, of course, lots of ways to resist progress. People take up knitting or quilting or calligraphy. They bake their own bread or brew their own beer or sew their own clothes using felt they have fashioned out of wet wool and dish soap. But, both in the scale of its ambition and in the scope of its anachronism, paleo eating takes things to a whole new level. Our Stone Age ancestors left behind no menus or cookbooks. To figure out what they ate, we have to dig up their bones and study the wear patterns on their teeth. Or comb through their refuse and analyze their prehistoric poop. And paleo eating is just the tip of the spear, so to speak. There are passionate advocates for paleo fitness, which starts with tossing out your sneakers. There’s a paleo sleep contingent, which recommends blackout curtains, amber-tinted glasses, and getting rid of your mattress; and there are champions of primal parenting, which may or may not include eating your baby’s placenta. There are even signs of a paleo hygiene movement: coat yourself with bacteria and say goodbye to soap and shampoo.

The result is a small library of what might be called paleo literature—how-to books that are mostly how-to-undo books. Such is the tenor of our time that the ultimate retro movement is lavishly represented on the Web. From a site called Paleo Grubs, I downloaded recipes for Delicious Paleo Carrot Cake Muffins and Paleo Apple Nachos, and from a site called Nom Nom Paleo I got instructions on how to make Paleo Krabby Patties and Civilized Caveman’s Apple Cinnamon Cookies. (All of these dishes rely heavily on ingredients—including “flour”—made from coconuts, a quirk that reminded me of “Gilligan’s Island” and its many coconut-shell contraptions.)

Three days into my family’s experiment in Stone Age eating, my sons were still happily gorging themselves on sausage and grass-fed steak. My husband was ruminating on the tenuousness of existence, and, probably true to the actual Paleolithic experience, I found that I was spending more and more time preparing the few foods that we could eat.

Agriculture was “invented” several times, in different parts of the world, by people making use of the plants they found growing wild around them. The first time was probably about ten thousand years ago, in southeastern Turkey, when early farmers began cultivating einkorn wheat. The crop was a big hit, and, at least by the standards of the day, it spread rapidly. (This is sometimes referred to as the Big Agricultural Bang.) Wheat was being sown in Greece around eight thousand years ago, in the Balkans and in Italy seven thousand years ago, and in India and Scandinavia five thousand years ago. Meanwhile, around nine thousand years ago, a group of proto-farmers in southwestern Mexico began cultivating maize. It, too, quickly caught on, and was being grown in Panama seven thousand years ago and in Colombia six thousand years ago. Also sometime around nine thousand years ago, rice was domesticated in the Yangtze Valley.

In the standard account of human history, agriculture represents the ur-breakthrough. The domestication of plants and animals allowed people for the first time to build up surpluses of food. This, in turn, allowed them to think about something besides feeding themselves. They became merchants and priests and artisans and bookkeepers. They built villages, towns, and cities. Every subsequent innovation—metallurgy, writing, mathematics, science, and even paleo Web sites—could be said to owe its origin to those first farmers scratching with sticks in the dirt.

Agro-revisionists also regard the Neolithic Revolution as a critical event. They, too, believe that without it modern society wouldn’t exist. What they’re not so sure about is whether it was a good idea.

“The adoption of agriculture, supposedly our most decisive step toward a better life, was in many ways a catastrophe from which we have never recovered” is Jared Diamond’s dour assessment, offered in an essay titled “The Worst Mistake in the History of the Human Race.”

Like Stone Age hunter-gatherers, early farmers left little behind—just some burnt grain, mud foundations, and their own bones. But that’s enough to reveal how punishing the transition to agriculture was. According to a study of human remains from China and Japan, the height of the average person declined by more than three inches during the millennia in which rice cultivation intensified. According to another study, of bones from Mesoamerica, women’s heights dropped by three inches and men’s by two inches as farming spread. A recent survey of more than twenty studies on this subject, published in the journal Economics and Human Biology, found that the adoption of agriculture “was observed to decrease stature in populations from across the entire globe,” including in Europe, the Middle East, Asia, and South America.

Early farmers were not just shorter than hunter-gatherers; they were also more sickly. They had worse teeth—one analysis from the Near East suggests that the incidence of cavities jumped sixfold as people started relying on grain—and they suffered from increased rates of anemia and infectious disease. Many now familiar infections—measles, for instance—require high population densities to persist; thus, it wasn’t until people established towns and cities that such “crowd epidemic diseases” could flourish. And, by living in close proximity to their equally crowded farm animals, early agriculturalists helped to bring into being a whole set of diseases that jumped from livestock to people.