AMERICANS crave efficiency. We esteem cars that burn less gas for each mile driven, jobs that generate the most money per hour and mobile phones that pack the most capabilities into the smallest possible package. In short, we want bang for our buck.

But we skimp on efficiency when it comes time to eat, because we just can't resist meat. According to the United Nations Food and Agriculture Organization, Americans consume 275 pounds of animal flesh every year, more per capita than nearly any other populace on earth. (Floss, anyone?) This is an expensive habit in carbon terms; a 2007 study by the National Institute of Livestock and Grassland Science in Japan reported that producing 1 pound of beef produces the same amount of CO2 as does driving a small car 70 miles. And the waste of land is staggering; according to a U.N. report titled Livestock in a Changing Landscape, almost one-third of the Earth's ice-free land surface is devoted to livestock production, while only 8 percent is devoted to production of food consumed directly by humans (i.e., plants). As the earth's human population escalates, with a population of 10 billion expected by the year 2050, the stresses on our planet's resources will follow—especially if we continue to bring home the bacon and butcher the beef.

So what if we just cut big mooing, grunting mammals from the equation and looked to another source of protein? Something lower on the food chain, perhaps—like insects?

We wouldn't be the first large mammals to crunch them between their teeth. The great Ursus arctos, also known as the brown bear, will sink its teeth into elk and salmon when it can, but it also eats large quantities of moths, termites and ants, and for a creature so high on the food chain to stoop to the bottom for its sustenance is a model act of humility that humans might do well to emulate. Insects and other arthropods, like most "lower" forms of life, abound, constituting an edible resource of tremendous biomass. Ants alone reportedly approximate about one-third of all terrestrial animal biomass, according to ecologists' models. Add termites, moths, spiders and cockroaches to the menu, and we suddenly have a bounteous resource scuttling about innumerably at our feet, in the cracks and crevices and vile damp places of the earth, a vast source of protein and minerals almost entirely untapped.

Eating bugs just makes sense, so much so that the U.N. is giving consideration to the matter. In February 2008, the Food and Agriculture Organization hosted a workshop called "Forest Insects as Food: Humans Bite Back," in Chiang Mai, Thailand, at which 36 entomologists, edible insect nutritionists, foresters and others with a stake in the developing edible insect movement discussed the potential of six-legged animals as food and the challenges of developing a market and industry. The BBC reports that a handful of Dutch companies have already begun breeding beetles, crickets and locusts for food. Even here in the United States advocates are pushing the concept. The entomology department of Iowa State University posts online nutritional information about eating insects, while numerous cookbooks, including Creepy Crawly Cuisine: The Gourmet Guide to Edible Insects by Dr. Julieta Ramos-Elorduy, tout the wisdom and sense in eating earth's most abundant terrestrial animal resource and offer recipes like fried grasshoppers, ant larva tacos and mealworm cookies. Eminent entomologists, like Dr. Gene R. DeFoliart, a bug-eating advocate at the University of Wisconsin well-known to many in the insectivorous community, also vouch for insects as food. And some high-end restaurants, like Mezcal in San Jose and the increasingly famous Typhoon at the Santa Monica Airport, are putting insects on their menus.

You might say the insectivore movement is gaining legs. And they're wiggling.

Bottoms Up

Just why creatures can be categorically defined as sustainable or not-so-sustainable food sources can be understood with a quick look at the trophic energy scale, or pyramid, a conceptual representation of organisms and the energy each one requires to grow and reproduce. At the top of the pyramid are the meat-eating apex predators, like bluefin tuna and tigers. At the bottom are the simplest organic building blocks of life, like algae and phytoplankton, which often require little more than sunlight to grow. In terms of biomass, there is very little of the former and vast quantities of the latter.

The critters at the bottom of the trophic pyramid are better choices for food, but not just because they're plentiful. They're also efficient. It is through algae and phytoplankton that the energy of the sun is first absorbed into the food web through photosynthesis. As energy ascends the pyramid, however—from the phytoplankton to the krill to the sardines to the tuna, from the bacteria to the grasses to the grazers to the carnivores—energy efficiency is lost rapidly. For every pound of flesh at the top of the trophic pyramid, immeasurable quantities of energy have been expended to make it.

Casson Trenor, the senior markets campaigner with Greenpeace and a former sustainability consultant with the Santa Cruz–based nonprofit FishWise, explains basic trophic math using two of the creatures he knows best: tuna and sardines.

"To take our protein from the level of tuna is a totally inefficient use of the ocean," says Trenor, who in 2007 founded the sustainable sushi restaurant Tataki in San Francisco, and who will receive Save Our Shores' Ocean Protection Hero of the Year award at Toast to the Coast on Aug. 21. "If we want a pound of protein, we could get it from sardines. If we need to get it from tuna, it might have taken 15 pounds of protein from sardines to make that pound of tuna protein."

The lower we eat on the food chain, the more sustainable our diets become. The invertebrate level is a good place to settle down and make a meal, for these spineless species are excellent processors of energy. On average, invertebrate species utilize 20 percent of assimilated energy (i.e., food ingested and not pooped out) for growth and reproduction. Vertebrates, by contrast, use just 2 percent of assimilated energy for growth and reproduction, the balance being used for nothing but fueling motion and metabolism.

Of course, a vegetarian diet is the most sustainable long-term nutrition plan of all. Plants not only draw their energy directly from the sun via photosynthesis, they do it efficiently, directing up to 85 percent of assimilated energy toward making more of themselves. Algae can double their biomass in hours just by soaking up the sun.

But the food business is show business, and no chef attains rock star status by boiling primordial broths of microscopic nourishment. They gain fame by carving up beasts and grilling them. A restaurant in New Jersey called Café Arugula has even served up retired circus cats—read this as "roasted leg of lion"—at expensive special event dinners. The chef told us about it himself.

All the Little Fishes

In Menlo Park, Flea Street Café's food director and lead cook Carlos Cañada recognizes the virtues of serving small animals, and one of the restaurant's most popular items is the fried sardines. From a business perspective, serving such fish pays off, Cañada says. Grade-A yellowfin tuna belly may cost $14 per pound wholesale, but sardines set Cañada back just $1.95. "And there's very little waste," he says. Cañada believes the low cost of sardines reflects their natural abundance in the ocean, and he believes that building a customer base happy with finger-sized fish is a sustainable long-term business model—much more so, anyway, than thrilling guests with grilled lion and tuna, neither of which Flea Street Café serves.

At the EcoFarm Conference in Pacific Grove last January, where restaurateurs and food producers convened to discuss sustainable food production, sardines were a hot topic of discussion. That sardines have become an esteemed item in the culinary world gives Trenor at Greepeace reason to hope.

"Sardines are a powerful indicator of change in the seafood industry," Trenor says. "Sardines have been out of favor for a long time. They've been the poor man's food, processed down by the train tracks and eaten out of a tin."

At FishWise, Bill Wall, business partnership program manager, says the economic downturn combined with a increased awareness of ecological dynamics has spurred interest in small fishes, squid and other mollusks.

Flea Street Café owner Jesse Cool believes a social change in the perception of what is edible is unraveling—that people are coming to understand "the value of eating diversely, eating beginning to end, and not just eating what has been made appealing commercially, like salmon, bass and halibut." This includes using all parts of an animal. Cañada scrapes the last bits of flesh from filleted fish carcasses and uses the scraps for carpaccio. The bones, finally, are used for soup. To use all parts of an animal "is spiritually and karmically right on," Cool says.

Squid, too, are a great choice for diners hunting low on the trophic scale. Lou Zeidberg, a researcher in Monterey working for UCLA, says, "Unless you eat anchovies and sardines, you aren't going to get any closer to phytoplankton than with squid." Sardines and anchovies both filter phytoplankton from the water. Squid—voracious predators, even the four-inchers—do not eat phytoplankton, Zeidberg says, but they eat the copepods and the baby fish that do. Moreover, squid grow marvelously fast, a key point in true sustainability. The familiar market squid—the sort usually dredged in flour and fried—rarely lives more than eight months, according to Zeidberg. Its rapid life cycle helps make the population resilient.

Like a lot of Santa Cruz restaurants, Ristorante Avanti serves fried squid, or calamari, and has for years. Availability, says owner Paul Geise, has rarely been a limiting factor at any time of the year. Sardines are almost as reliably available, he says, and have been on the menu for 15 years, though popularity of sardines is trending upward.

Those wishing to cook some low-order prey species at home can find squid, anchovies and sardines periodically at H&H Fish at the farmer's market and Phil's Fish Market and Eatery in Moss Landing. New Leaf Markets will supply these smaller species upon request (though when we checked, the Pacific Avenue location had none). Wall at FishWise says retailers that don't regularly stock smaller fishes and mollusks may just need to be encouraged. "The best way to see the items in the case is to ask your fishmonger to let them know there is a demand for lower trophic level items," Wall says.

He adds that there are health, and not just ecological, benefits to eating species closer to the trophic base: "Seafood lower in the food web is typically lower in mercury and contaminants too. Mercury and PCBs bioaccumulate, meaning they are found in greater concentrations higher in the food web. As a shark eats many small fish with low mercury levels, all of the mercury consumed by the shark remains in the tissue, making the mercury content of the shark many times more than the fish it eats." The same rule applies to tuna, infamous for its potentially dangerous densities of mercury.

Jiminy Bar Snacks

Those uninterested in seafood but wanting more than veggies might aim in between, at the meek of the earth. One place to try eating insects is Mezcal in San Jose, which serves grasshoppers. The appetizer, called chapulines, is a traditional item from Oaxaca, the original homeland of owner Adolfo Gomez and his brother, chef Octavio Gomez. The hoppers are toasted in a hot pan with chili powder, salt and lime juice. Many customers rave about them on Yelp, though the most common complaint is of their mouth-burning saltiness. Reportedly the crunchy hoppers go well with beer. Mexican markets in Santa Cruz County also offer them from time to time (see sidebar, page 19.) Hint: try Hernandez Market on Portola in Santa Cruz.

But insects need not be rendered into mere bar food, and cooking them at home can produce creative and tasty dishes, both savory and sweet. Iowa State University's entomology department website recommends recipes. One is for a "rootworm beetle dip," no small portion of which is beetles—a full cup of them, dried and roasted. The site also includes recipes for "banana worm bread," chocolate chip cookies with dried crickets crumbled into the dough and "mealworm fried rice" calling for equal parts rice and larvae. According to the same website, 100 grams, or about a cup, of grasshopper contains 20.6 grams of protein, 6.1 of fat and 3.9 of carbohydrates. (A 3-ounce portion of lean beef—just under a quarter-pound—contains 27.4 grams of protein.) Caterpillar contains 28.2 grams of protein per 100 grams. The same volume of dung beetle contains 17.2 grams. And crickets are high in calcium.

Cañada traveled recently in Oaxaca and tasted the local chapulines. The critters were delicious, he says, nutty and crunchy—though the feeling of the legs and brittle body sections shattering over his tongue gave him the willies. Cañada says he might be persuaded someday to cook them himself, though they won't appear on Flea Street Café's menu anytime soon—at least not before we run out of sardines.

Send letters to the editor here.