A controversial petition by the dairy industry to allow milk sweetened with aspartame or other alternative sweeteners to be labeled on the front of the carton simply as MILK is drawing criticism from the nation's leading group of nutritionists.

The Academy of Nutrition and Dietetics is urging the FDA to reject the petition, which we first told you about in March.

"The Academy's recommendation to deny the petition is not based on the safety of artificial sweeteners," writes Ethan Bergman, the group's president, in a release explaining its opposition.

So what's the academy's rationale? Well, as we previously reported, the petition is aimed at boosting consumption in schools, where many kids have decided that milk is not their drink of choice. Given the options of water, juice or milk, milk is losing out.

Studies show that offering flavored milk such as chocolate or strawberry turns more kids onto milk, but critics have pointed to the extra sugar as a drawback.

In an effort to get around the sugar problem, the dairy industry has petitioned to change what's known as the "standard of identity" of milk, which is basically the definition of milk, allowing aspartame or alternatives such as stevia to be used to sweeten the milk.

So what's the academy's beef with the petition? Well, it goes back to the assertion that the dairy industry makes in its petition that the change (allowing no or low-calories sweeteners in milk) could promote healthful eating and help reduce childhood obesity.

Not necessarily, says the academy.

"Flavored milk is not a major source of added sugar in children's diets," says Bergman.

The academy points to studies, including this one, that show that school-age kids who drink flavored (chocolate and strawberry) milk meet more of their nutrient needs, and don't consume more added sugar, fat or calories. These kids are also "similar in weight compared to non-milk drinkers," according to a statement released by the academy. In other words, there's no need to try to cut sugar and calories with artificial sweeteners.

And there's criticism among consumers, too.

A petition by the group Sum Of Us, which says the goal of the dairy industry petition is to "turn the wholesome drink (milk) into another artificial flavor-laden sweet snack," has received about 117,000 signatures.

Raising chickens has become so fashionable among some urban Americans that there's now a market for chicken diapers, as we reported this month.

For a bit of a reality check, let's consider what it means to raise urban livestock in the developing world, where people are poorer and hungrier, and cities are much more densely populated. It's a starkly different picture of people and animals living together, and the question of how it's done has major implications for improving food security and preventing public health disasters.

While humans have been raising food animals in their homes for thousands of years, what's different now is that they're doing it with so many other humans crammed next to them.

And they're not just feeding their families: They're feeding their neighbors, too. Worldwide, 34 percent of meat and nearly 70 percent of eggs are produced in urban areas, according to a 2008 report by the World Bank and the Food and Agriculture Organization. In Maputo, Mozambique, for example, a city with about 1.2 million people, 37 percent of households produce food and 29 percent raise livestock.

"Those moving from rural areas to the cities are bringing their livestock with them, often keeping them in close confinement inside the slums," Delia Grace, a veterinary epidemiologist and food safety specialist, tells The Salt. "People keep livestock like chicken, ducks, goats and even cows because there's huge demand for them, and they're profitable."

Grace, of the International Livestock Research Institute in Nairobi, Kenya, is studying these huge new city ecosystems. In a series of papers she's published in the past several months in various scientific journals, she has looked at the risks and benefits of urban livestock in the developing world.

When it comes to risks, Grace says she's most worried about what happens to the animal waste — especially in places where human waste isn't even managed well. And she's worried that sick animals that go untreated lead to zoonoses — diseases that spread from animals to humans. One of her recent studies, published in the journal Tropical Animal Health and Production, found that zoonoses and diseases recently emerged from animals make up 26 percent of the infectious disease cases in low-income countries.

"We're talking about the everyday events of disease spreading from animals to humans, and the rare but more serious event of the emergence of a new disease," she says. "Slums could be a good test tube for growing new pathogens, because people are poor and malnourished, and there's generally just more disease."

Meat and eggs produced in slums also pose a food safety risk, she says. "There's often no refrigeration or cold chain for these products," she says.

But even with the risks, Grace argues there's a net benefit from people keeping urban livestock, and cities should be trying to help producers learn how to safely care for their animals and the food they produce.

According to her research, urban livestock generate income and improve the nutrition and health of communities they're in, because the animals are a source of fresh food for local consumers. When cities try to ban urban livestock, it backfires, she says. "We found that the more people were harassed by the police about their animals, the fewer precautions they took," she says.

Pierre Ferrari, CEO of Heifer International, a nonprofit that targets hunger and poverty by supplying communities with livestock, agrees that urban livestock can be a tremendous nutritional resource for the poor — if waste is well-managed and veterinary care is available.

"Nutrition is more important than calories, and animal-based foods are very high-quality, nutritious food," he tells The Salt. "But you also need good nutrition for the animal, and many people are not in the position to keep a cow well fed, which is why we recommend smaller animals, like goats, sheep, rabbits and guinea pigs."

According to Ferrari, two of Heifer's most successful urban livestock projects include a guinea pig operation in Cusco, Peru, and a community in Accra, Ghana, that produces grasscutters, rodents prized there as a delicacy.

"These animals use feed very efficiently, and you can keep them in relatively small cages," says Ferrari.

In fact, Ferrari recommends guinea pigs over chickens to just about anyone living in cities. Listen up, hipsters: Guinea pigs may one day need their own fashion line, too.

The idea of vertical farming is all the rage right now. Architects and engineers have come up with spectacular concepts for lofty buildings that could function as urban food centers of the future.

In Sweden, for example, they're planning a 177-foot skyscraper to farm leafy greens at the edge of each floor. But so far, most vertical gardens that are up and running actually look more like large greenhouses than city towers. And many horticulturists don't think sky-high farms in cities are practical.

"The idea of taking a skyscraper and turning it into a vertical farming complex is absolutely ridiculous from an energy perspective," says horticulturist Cary Mitchell of Purdue University, who's been working on ways to grow plants in space for more than 20 years.

The future of vertical farming, Mitchell thinks, lies not in city skyscrapers, but rather in large warehouses located in the suburbs, where real estate and electricity are cheaper.

And oh, yeah, instead of being traditional greenhouses lit by fluorescent lamps, he says these plant factories will probably be "pinkhouses," glowing magenta from the mix of blue and red LEDs.

Light is a major problem with vertical farming. When you stack plants on top of each other, the ones at the top shade the ones at the bottom. The only way to get around it is to add artificial light — which is expensive both financially and environmentally.

Vertical farmers can lower the energy bill, Mitchell says, by giving plants only the wavelengths of light they need the most: the blue and red.

"Twenty years ago, research showed that you could grow lettuce in just red light," Mitchell says. "If you add a little bit of blue, it grows better."

Plant's photosynthesis machinery is tuned to absorb red and blue light most efficiently. They have a handful of other pigments in their leaves that catch other wavelengths, but the red and blue wavelengths are the big ones, supplying the majority of the light needed to grow.

So why LEDs? They're super energy efficient in general, but unlike traditional greenhouse lamps, they can be tuned to specific wavelengths. Why use all of ROYGBIV when just RB will do?

And there's another advantage to using LEDs in greenhouses and vertical farming, Mitchell says: Because these lights are cooler, you can place them close to the plants — even stacked plants — and lose even less energy.

Recently, Mitchell and his graduate student designed a 9-foot-tall tower of lights and grew tomato plants right up against it. "As the plants get taller, we turn on the [light] panels higher up," he explains. "It takes about two months before all the panels are on."

The towers cut energy consumption by about 75 percent, Mitchell and his team reported earlier this year.

Right now, experiments are using these specialized LEDs to supplement natural light, not replace it.

But as LEDs get more and more efficient, could growers forgo the natural light altogether and grow crops completely in enclosed rooms, where they're protected from temperature changes or damaging pests?

That's exactly what Barry Holtz, at Caliber Biotherapeutics, is already doing.

His farms have never seen the light of day.

He and his company have built a 150,000-square-foot "plant factory" in Texas that is completely closed off from the outside world. They grow 2.2 million plants, stacked up 50 feet high, all underneath the magenta glow of blue and red LEDS.

"A photon is a terrible thing to waste," Holtz tells The Salt. "So we developed these lights to correctly match the photosynthesis needs of our plants. We get almost 20 percent faster growth rate and save a lot energy."

Holtz is growing a tobacco-like plant to make new drugs and vaccines. The indoor pinkhouse gives him tight control over the expensive crops, so his team can stop diseases and contamination.

Holtz says this type of indoor gardening isn't going to replace traditional farms anytime soon. It's still relatively expensive for growing food. "We couldn't compete with iceberg lettuce farmers," he says, "but for certain specialty crops, the economics wouldn't be so bad."

And, he says, the pinkhouse is actually quite efficient when it comes to water and electricity. "We've done some calculations, and we lose less water in one day than a KFC restaurant uses, because we recycle all of it."

William von Schneidau, an intrepid butcher in Seattle, is giving a whole new meaning to "potbelly pig." Lately, he's been feeding marijuana refuse to the pigs he turns into prosciutto for BB Ranch, his butcher shop in the city's famous Pike Place Market.

Pot-scented bacon? Well, not quite.

The stems, leaves and root bulbs von Schneidau recoups from Top Shelf Organic, a medical marijuana dispensary, don't season the meat, he says. But the meat from the first few "pot pigs" he's butchered has been "redder and more savory" than what he usually works with, he says.

It's not clear whether the pigs feel anything from the weed in their feed, or how much, if any, THC — the psychoactive substance that gets humans high — ends up in the meat. Rather than an attempt to develop a new meaty treat for stoners, the "pot pig" experiment seems mostly to be an (effective) publicity stunt. Von Schneidau's first Pot Pig Gig event — where he promoted the product, as well as other local foods — sold out quickly. And he says all the media attention he has gotten is generating lots of interest in the next event he's planning.

Still, von Schneidau's creative reuse of a local waste product is part of a larger trend of small farmers looking for new, free sources of livestock feed, especially since prices for corn and soy have been on the rise. In addition to the pot refuse, von Schneidau has linked up ranchers and farmers in the region with a vodka distillery and with vegetable vendors at Pike Place Market who have waste that would otherwise end up as compost or in the landfill.

As we've reported, high feed prices have led some farmers elsewhere to seek out food scraps and even bakery byproduct — bread, dough, pastries and cereal — for their pigs and cattle.

Pigs have stomachs pretty similar to humans and can eat just about anything we eat. But we couldn't find any research on what happens when you feed them marijuana.

Scientists at the European Union Food Safety Authority looked into the safety of using hemp, a plant that's a close relative of marijuana, in feed for dairy cows. When the cows were fed hemp plants, enough THC made its way into their milk that the scientists recommended prohibiting its use. (However, feeding the cows hemp seeds was just fine, they found.)

Von Schneidau says he's all for finding out what his dietary supplement is doing for his pigs.

"If we had a vet that stepped up to the plate and wanted to check out their joints and mood, and what drugs make pigs happy, that would be great," he says. "But me, I just get out there, and cut them up, and put them on a BBQ, and eat them."

One way to know how much soda people drink is to ask them.

The problem? We tend to underestimate, lie or forget what we've consumed.

And this is a challenge for researchers who study the links between sugar-sweetened beverages and obesity.

A new study published in the Journal of Nutrition explains a technique that could help researchers get a good measurement of sugary beverage consumption — by analyzing a piece of hair or a blood sample.

Researcher Diane O'Brien of the University of Alaska and her colleagues have used carbon isotope analysis to develop their measuring tool. "We're isolating the [carbon] isotope ratio in a specific molecule," explains O'Brien. The molecule is an amino acid called alanine, which captures carbon from sugars.

It turns out that when you consume sweetened soda, slightly more of a particular kind of carbon called C-13 gets trapped in alanine and incorporated into proteins. And proteins hang around in the body much longer than sugar does. So the scientists say they can sample proteins to look for extra amounts of C-13 in alanine. People with a lot of C-13 are likely to be people who have consumed a lot of corn syrup and cane sugar.

Using this technique, O'Brien says, you can capture a longer-term picture of sugar consumption compared with urine samples — which only reveal how much sugar a person has consumed in the past day or so.

Carbon isotope analysis has helped scientists piece together ancient dietary patterns, explains Dale Schoeller of the University of Wisconsin, Madison, in a commentary about the study: "The use of stable isotope signatures has even provided information about the diet of Otzi [aka The Iceman],the 5,000-year-old natural mummy found in the Alps in 1991."

And he writes that he thinks the technique will be helpful for researchers studying the obesity epidemic.

"This should be a major step toward resolving the controversy over the role of
caloric sweetener intake in the development of obesity," writes Schoeller.

Not everyone is convinced.

"This is an interesting, but preliminary, finding," says Dr. David Ludwig of Boston Children's Hospital and director of the New Balance Foundation Obesity Prevention Center, in an email to The Salt.

Barry Popkin of UNC-Chapel Hill, another obesity researcher, sounds the same note: "This might be useful," Popkin writes in an email. But the big drawback, he says, is that such testing is expensive to carry out.

Still, as the mom of a teenage son who has been spotted more than once sneaking off on his bike to the corner store for a big old soft drink in the afternoon, it would be nifty to perform the r-u-drinking-soda? test.

So can O'Brien help?

"Sure, in theory we could run your son's hair and find out if he's quaffing on the sly," O'Brien says.

Or maybe I should just check the bottles in the recycle bin. ('Fess up, Luke, I'm on to you!)

It takes a lot of chutzpah to reduce one of the most powerful men on Earth to a pile of fruits and vegetables.

Luckily for art lovers, Giuseppe Arcimboldo had nerve to spare.

Arcimboldo created this unorthodox produce portrait of Holy Roman Emperor Rudolph II back in 1590. By that time, the Italian artist had been painting for the emperor and his powerful Habsburg family for more than 25 years, so presumably, they'd grown used to his visual jokes. (The emperor has "peachy" cheeks and "ears" of corn, get it?)

Though he also dabbled in the angels and saints that were the standard stuff of art in his day, Arcimboldo is best known for his "scherzi" or "capricci" — "meaning jokes or games," as David Brown, a curator at the National Gallery of Art, explains in this video.

"It's very clear that's how they were meant to be seen," Brown says. "They were a source of amusement or entertainment, because there was this element of surprise."

That they also often feature an element of fruits, berries or other foods is partly a reflection of the Renaissance blossoming of natural sciences, like botany.

"At a distance, they just look like heads in profile or three-quarter view," Brown says. "Up close, they look like an incredible variety of nature's wonders."

That talent for upending the viewer's expectations helps explain why Arcimboldo — whose work, Brown says, fell into "virtual oblivion" after his death — found new champions among 20th-century modernists. (Picasso and Salvador Dali were among his fans).

The latest to pay homage to this Renaissance man is American Philip Haas, an Oscar-nominated filmmaker (for Angels and Insects) and contemporary artist. This weekend, the New York Botanical Garden opened a new exhibit featuring Haas' giant, 15-foot-high fiberglass sculptures based on Arcimboldo's "Four Seasons" — winter, spring, summer and fall personified as people, crafted of foods, trees and other natural elements.

As in the originals, Haas' sculptures contain clues to the foods of the 16th century, when Arcimboldo painted. Winter is a craggy-faced old man, and his "cravat" is made of oranges and lemons — imported from the warmer south, they were one of the few fruits that could be seen in Renaissance Italy during the colder months.

Summer's bounty — in the shape of a young man, naturally — includes eggplant in his skull and corn ears, two crops introduced to Europe from Asia and the New World.

A fall-ripening gourd caps Autumn's head. Figs dangle from his ears. The grapes that tumble from his head like hair and fill his wooden barrel chest both nod to Italy's fall wine-making season.

Like Arcimboldo, Haas says he was attracted by the idea of playing with context and viewer's expectations. "Arcimboldo was making a painting from the natural world, and then he turned it into a painting and [others] stuck it in a museum," Haas tells The Salt. "I took it out of the museum and put it back into the natural world."

The sculptures have been on a tour of Europe and the U.S., where they were most recently on display at the Desert Botanical Garden in Phoenix.

By transforming Arcimboldo's seasons into colossal 3-D sculptures, Haas says he aims to change how the viewer experiences not just the art but the natural world that surrounds them, too.

"Summer's head has a cucumber for a nose," he notes. "When that head was in Phoenix, suddenly it looks like a cactus. The works are quite elastic — they respond to the environment."

Back in 2009, Katie Shelly was craving an eggplant Parmesan. Small problem: She'd never made it before. But she remembered that a college roommate used to make it, so she called her up and asked for the recipe.

The friend told her she needed to start with three bowls — one for breadcrumbs, one for egg and one for flour, salt and pepper. "In that moment, it was totally natural for me to just draw the three bowls instead of writing all that out in words," says Shelly, whose day job is as a visual designer.

As the friend continued the recipe, Shelly continued drawing it out with arrows and eggplant slices on a tray. When she pulled out the scrap of loose-leaf in the kitchen, she found it much easier to cook from that than a traditional recipe that relies on numerical steps.

And that's where the idea for Shelly's upcoming cookbook, Picture Cook, originated. The book is filled with 50 illustrated recipe "blueprints" for basic meals — from snacks like Krispy Kale to more hefty dishes like White Lasagna. Her recipes are bound to appeal to visual learners; Shelly hopes they're also less daunting than traditional recipes.

"If you pick up a book from Emeril Lagasse or Julia Child or Mario Batali or whoever, there's a little bit of intimidation there. ... But this book is just coming from little old me. You don't have to feel like you're going into a Top Chef competition with whatever you create."

In fact, she doesn't think she's "exceptionally culinarily inclined" — "I make food that is tasty and does the job," she says. But she learned to cook by experimenting with her friends and hopes learning by seeing will encourage others to improvise as well.

Already, lots of people seem to have responded to her novel approach to recipes: Traffic to her website exploded after the illustration blog Drawn featured her carrot soup recipe in 2010.

Other design blogs picked up the illustrations, Mark Bittman tweeted about her, and people were emailing to ask where they could buy her book. Picture Cook didn't exist yet, but all the positive feedback from the online community motivated her to start talking to publishers. Three years later, her book is close to hitting the shelves: It comes out in October but is available for pre-order now.

Shelly recognizes that while some people love the illustrated recipes, others find them confusing.

"It's just another way of slicing information," she says. "There will always people who prefer the original way of doing recipes, and if you're in that camp, then no need to buy this book. I'm not suggesting that the whole world switch over to this format. But I think for people who are into it, if it works for you, then that's awesome."

Two seemingly common-sense, bipartisan food reforms have gotten mugged on Capitol Hill in recent days. If you're a loyal reader of The Salt, you've heard of them.

First, there's the proposal — backed by an odd-couple alliance of egg producers and animal-welfare activists — to set minimum standards for the housing of egg-laying chickens. Second, the Obama administration wants to change the way the United States provides food aid to people in foreign countries, buying more of that food close to where it's needed.

Neither proposal seems, at first glance, controversial. Changing the rules for food aid should save money, according to most independent analyses, allowing the program to feed more hungry people. Similar reforms, in fact, were proposed by President George W. Bush. The "egg bill," meanwhile, is a remarkable instance of pragmatic compromise between bitter adversaries.

Any change, however, threatens somebody, and both of these proposals have run afoul of politically well-connected people.

In the case of food aid, the skeptics include American shippers and dock workers, who will get slightly less work if the U.S. sends cash to buy food abroad. They, in turn, have a powerful friend in Congress: Sen. Barbara Mikulski, proud native of the port city of Baltimore and chairwoman of the Senate Appropriations Committee. In an e-mail to NPR, Mikulski wrote that "we need to find a sensible center that will allow us to implement smart reforms without jeopardizing U.S. jobs, particularly those in the maritime industry."

In part because of Mikulski's resistance, advocates of reform are now trying a different route entirely — a free-standing bill that's been introduced by Edward Royce, the Republican chairman of the House Foreign Affairs Committee. Its prospects are uncertain.

The "egg bill," meanwhile, has some influential supporters. Secretary of Agriculture Tom Vilsack brings it up frequently as an exemplary compromise between large-scale agriculture and its critics. Debbie Stabenow, D-Mich., chairwoman of the Senate Agriculture Committee, actually tried to include it in her draft of the farm bill, which is up for renewal (again) this year.

Pork and beef producers, however, object in principle to the notion of federal regulation of farm animal housing — even though, in this case, the egg producers themselves are asking for federal regulations as a way to pre-empt state rules that are more troublesome.

When the agriculture committees of both House and Senate finished their versions of the farm bill this week, all mention of guaranteed living space for egg-laying hens had vanished.

In fact, the House committee adopted a provision that could make it more difficult for states to set such standards. This amendment, offered by Rep. Steve King, R-Iowa, would prohibit any effort by state governments to control the way that their food is produced by out-of-state farmers. The measure is aimed specifically at California's Proposition 2, which is set to ban farmers in Iowa or Idaho from selling their eggs in California if those eggs come from chickens housed in traditional cages.

American gourmets and lovers of Italian food products, your days as food smugglers are over.

No more stuffing your suitcases with delicacies bought in Italy, hoping the sniffer dogs at JFK or other American airports won't detect the banned-in-the-USA foodstuffs inside your luggage.

In the U.S., they're called cured meats, the French say charcuterie and in Italy, the word for cured-pork products is salumi.

Starting May 28, a four-decades-old ban on the import of many Italian salumi will be lifted.

The U.S. Department of Agriculture has announced that the Italian regions of Lombardy, Emilia-Romagna, Veneto and Piedmont, and the provinces of Trento and Bolzano, are free of swine vesicular disease. Imports of pork products from those areas, says the USDA, present a low risk of introducing the disease into the U.S. The disease was first detected in the 1960s and can survive cooking and even long curing.

Up to now, only a few Italian pork products were approved for import to the U.S.: prosciutto di Parma and prosciutto di San Daniele, as well as mortadella — which was also banned until 2000.

Starting soon, as long as they receive USDA approval, hundreds of artisanal products will arrive on American tables. It's not yet clear, however, what standards the producers will have to meet and what the costs will be. But even without a ban, Italian cured meat producers must pay hefty fees as part of the process of getting certified for importation.

For centuries, Italians have been making some of the highest-quality cured meats in Europe. It's time to start learning some of their names: sopressata, a slow-cured dried pork, similar in appearance to salami; pancetta, bacon made from the pork belly, but unlike the American variety, which is smoked, Italian pancetta is cured in salt and spices; coppa or capocollo, made from pork shoulder or neck and seasoned with wine, salt and spice.

What's the secret behind the high quality of Italian salumi?

Many say it's the quality of the pigs, the climate where they're raised and what they're fed.

Every Italian region and province, and even many towns have their own distinctive salumi, many of them celebrated in weeklong folk festivals. There are fans of Coppa Piacentina or those who swear by Coppa di Parma; there's an infinite variety of salamis — from Brianza, Vicenza, Cremona and many more, spiced with garlic, juniper and myrtle berries, fennel and red wine.

One of the delicacies that may soon reach U.S. shores is salame di Felino, named after the small town of the same name near Parma.

According to the website prosciuttopedia, salame di Felino traces its origins to the Middle Ages. The oldest pictorial representation is found in the Parma Baptistery, where one can see two salamis draped over a saucepan. And in 1905, the wording "Salame di Felino" was officially included in the dictionary of the Italian language.

But what cured meat aficionados are most eagerly waiting for is the king of Italian salumi, culatello, a product of the flatlands of Zibello and neighboring towns near Parma — a product whose secret ingredient is the dense winter fog that hovers at a particular bend in the Po River.

Culatello dates back at least to the 15th century. It's made with the muscular part of the hind leg of pigs born, raised and slaughtered in the Emilia-Romagna and Lombardy regions.

The Italian poet Gabriele D'Annunzio, a culatello enthusiast, wrote in 1891, "It is aged only in the square of land surrounding Zibello, where the air of the Po is often humid and good for the mold that preserves this fatless cut of meat."

I first experienced culatello at the Trattoria La Buca di Zibello, a long-established restaurant run for four generations solely by women. A huge room is dedicated to curing the zibelli — hundreds hang from the ceiling. The women told me one of the key steps is a loving massage that helps salt penetrate the meat.

Culatello is an expensive delicacy even in Italy, and of the two culatelli produced by the same animal, one is always better than the other: It's said that pigs are animals of habit and always sleep on the same side, which ends up being the less tender of the two thighs.

But there are some cured pork products that won't soon be imported to the U.S. The region of Tuscany is still on the USDA-restricted list. So, you'll still have to travel there to savor wild boar sausages (my favorite) and finocchiona of Siena, a fennel-flavored salami.

And then there's that most sinful of products (sinful for those who have to watch their cholesterol intake), lardo di Colonnata, the small town perched above the marble quarries of Carrara. That velvety white lard — pork fat from the back of the pig — is cured in marble vats. Locals claim it's the porous quality of the stone that's responsible for its unique, refined taste.

Buon appetito.

Plenty of celebrities leverage their star power to raise awareness of complicated food issues. Some of the biggest names include Michelle Obama, Jamie Oliver, Prince Charles and Paul McCartney.

Down in New Orleans, actor Wendell Pierce, who stars in David Simon's Treme and, previously, The Wire, has been taking on food insecurity in low-income communities with brand new convenience stores. Pierce has received plenty of attention for his efforts and appeared this week on NPR's Tell Me More to talk about the opening of the first grocery store in his New Orleans-based Sterling Farms chain earlier this spring.

Even though New Orleans' restaurant sector is booming — there are over 1,200 in the city, even more than before Hurricane Katrina — many communities outside the center have been waiting in vain for supermarkets to return. That's because of investors' "economic apathy," Pierce says.

A food desert is defined as an area where the nearest grocery store is more than 10 miles away. And New Orleans has plenty of them, as the U.S. Department of Agriculture's new Food Access Research Atlas shows. "For me, growing up in New Orleans, where so much of the culture is based around food, it's unacceptable [to have them]," Pierce told Tell Me More.

But even with Pierce's leadership (he was recently named one of FastCompany's 100 most creative people in business) and investment dollars behind the effort, a host of stumbling blocks still make it hard to get fresh, healthful foods to people living in these areas. And as food activists are discovering all over the country, grocery stores alone won't make the food desert bloom.

This isn't Pierce's first foray into rebuilding New Orleans: After Katrina, he set to work building new energy-efficient homes in his neighborhood of Pontchartrain Park. That process was beset with delays and snafus — not unlike a lot of the scenarios that appear in Treme and The Wire. "It's life imitating art, and art imitating life," Pierce told the New York Times last year. "The shows influence me, and the work I do influences the shows."

Like his housing initiative, Pierce's retail food plan has been moving slowly. In addition to marshaling private funds, Pierce and his partners went after grants awarded through the Obama administration's Healthy Food Financing Initiative. Even with them, coming up with the financing for the project hasn't been easy.

"The most difficult part is making sure that everybody is on board when it comes to the banking institutions," Pierce said. The bankers, he said, had to be convinced that grocery and convenience stores would be viable business models in these communities.

Sterling Express is now operating two convenience stores, along with the new grocery store. The success of these ventures is ultimately going to depend on how well they can meet the needs of the communities they serve.

One issue is transportation. Sterling Farms is offering shoppers who spend $50 or more a free shuttle ride home — which might be more convenient than boarding a public bus with armloads of groceries. That option prompted this comment on Tell Me More's interview with Pierce: "Genius idea, as lack of transportation is a major stumbling block to folks getting access to quality, competitively-priced, heavy, fresh food choices!"

And as we reported last year, studies show that shoppers don't just care about cost and proximity to fresh produce — they also need choice and quality if they're going to buy it.

Mike Kantor, co-chairman of the New Orleans Food Policy Advisory Committee, commends Pierce's program. But he says there's another key part of the puzzle: making sure the poorest people in these communities are getting the food stamps, or SNAP benefits, they're entitled to.

"When we talk about food deserts, we can't just focus on location and geographic access," Kantor tells The Salt. "We have to talk about economic security, which means talking about programs the people going to shop at stores rely on in order to afford the produce that's sold there."

According to Kantor, more than 20 percent of households in the state of Louisiana live under the federal poverty line. While 77 percent of the people in the state who are eligible for SNAP are participating in the program, that coverage could be higher.

"And the actual benefit amount," he notes, "is barely enough for people relying on the program."

Climate change is gradually altering the fish that end up on ice in seafood counters around the world, according to a new study.

"The composition of the [global] fish catch includes more and more fish from the warmer areas, and cold-water fish are getting more rare, because the temperatures are increasing," says Daniel Pauly at the University of British Columbia, a co-author of the study.

As oceans warm — a result of climate change — fish maintain their preferred water temperature by moving away from the equator and toward the poles.

So, for example, people in Denmark are now encountering swordfish, which you'd normally find in the Mediterranean and off the coast of Africa.

"In British Columbia, where I live, we have Humboldt squid, giant squid from Mexico," Pauly says. "They eat all the herrings and stuff, and people don't know them. They are stranded on the beach, and people think they are sea monsters."

And fishermen have scuffled over Atlantic mackerel quotas, as the fish moves north to new grounds around Iceland.

The new study in Nature shows these anecdotes aren't simply a fluke. Data from fish catches from around the world show it's happening everywhere the ocean is warming — which is just about everywhere.

This trend isn't obvious at American fish counters. That's because 80 percent of our seafood is imported, and we don't know whether fishermen are catching our swordfish in the tropics or the North Atlantic. Also, half of all seafood is now produced in enclosures — not caught in the wild.

But if it's invisible to us, that's not the case for many people who rely on their local fisherman for protein.

"In the tropics, there are lots of developing countries' fisheries where their ability to adapt to changes in the resources is much lower," says William Cheung, the report's lead author. Like Pauly, he's at the University of British Columbia's Fisheries Center in Vancouver.

The paper documents a migration of some species out of the tropics, as they seek cooler waters. But there are no fish to replace the ones that are leaving. As a result, "these fisheries in the tropics will be most vulnerable to climate change impacts," Cheung says.

The United States will gradually feel the effects as well.

"Imagine a reef fish that is driven by temperature into North Carolina or the Delaware coast," Pauly says. "That reef fish will not find reefs. It's like you having to move, but you cannot take your furniture with you, or your house. That is the problem."

Many fish will have a hard time adapting to this very rapid change, he says.

Mark Payne at the National Institute for Aquatic Resources in Denmark was not involved in the research, but he's impressed by the result.

"This is suddenly a wake-up call," he says. "It's a strong suggestion that climate change is here. It's real, and it's really starting to affect what we catch and, therefore, what we eat."

Americans are repeatedly told to cut back on salt to reduce the risk of heart disease. But there are new questions being raised about the possible risks of reducing sodium too much.

So, how low should we go? Currently, the government recommends that Americans should aim for 2,300 milligrams per day. And people older than 50, as well as those with high blood pressure, diabetes or kidney disease are advised to reduce sodium even further, down to 1,500 mg per day.

But a panel of experts convened by the Institute of Medicine concludes in a new report that "the evidence on direct health outcomes does not support recommendations to lower sodium intake ... to or even below 1,500 mg per day."

Why? We asked the committee chairman, Brian Strom, a dean and professor of public health at the University of Pennsylvania, to summarize the panel's findings for us. "The net conclusion is that people who are eating too much sodium should lower their sodium, but it is possible that if you lower it too much you may do harm."

Strom says a lot more research is needed to better understand how ultra-low-sodium diets may be beneficial or harmful. Strom pointed to an Italian study of people with congestive heart failure as an example of research that has hinted that diets too low in sodium may be problematic for certain people.

"The people on the low-sodium diet actually did worse [compared to those on medium-sodium diets]," says Strom. "They had more hospital re-admissions and they had a higher mortality rate." He says it's unclear if the results would be the same for Americans with congestive heart failure, since treatments here are different than they are in Italy. But, he says, the findings raise questions.

The American Heart Association, which recommends a low-sodium (1,500 mg) diet for all Americans, released a statement stating that it disagrees with the key findings of the new report.

And some preventive health experts are critical, too. The World Health Organization has concluded that elevated blood pressure is the leading cause of preventable death, which suggests that staving off high blood pressure with low-sodium diets is an important strategy.

"Sodium reduction remains a critically important component of public health efforts designed to ... prevent cardiovascular disease," Lawrence Appel of Johns Hopkins University writes in an email.

Appel points out that the studies that suggest that low-sodium diets are harmful tend to focus on "sick populations in which illness leads to low sodium intake rather than the reverse."

Some groups of Americans, including older adults and African-Americans, are especially sensitive to the blood-pressure lowering effects of cutting sodium, Appel says. So the strategy of aiming for low-salt diets has "tremendous potential to reduce racial disparities in blood pressure-related cardiovascular disease."

The bottom line, according to Bonnie Liebman, director of nutrition for the Center for Science in the Public Interest, is that Americans are eating way too much salt, on average about 3,400 milligrams a day.

"And we know that much is harmful," she says. "It increases blood pressure, which increases the risk of heart attack and stroke."

And she says focusing on the potential risks of a very-low-sodium diet distracts from the more important conversation about how to get Americans to start consuming less.

To better understand just how much salt is found in the typical lunch out, I met Liebman at a food court.

Our first stop was McDonalds, where it turns out burgers have about twice as much salt as the fries: 1,000 mg, and up to 2,000 if you get the Angus bacon burger, Liebman says.

Put the burger and fries together and you've already reached the recommended daily sodium intake. Liebman says it's a similar story at every chain, from Subway to Chipotle to Pizzeria Uno. (McDonalds has pledged to reduce sodium 15 percent across its menu by 2015.)

So even though the new study raises questions about potential harms of ultra-low-sodium diets, with a food supply like ours, most of us consume way too much salt, not too little.

Yes, we talk a lot about eating bugs here at The Salt. We know, because some of you have complained about it.

But insect cuisine isn't just a crazy fad for Bay Area and Dutch foodies, or for Israelis plagued by locusts: In a report out this week, the U.N.'s agricultural arm makes the case for why insects should be an option for dinner.

The Food and Agriculture Organization has been pondering bugs as a protein source since 2003, but in the new report, the agency argues that insects might be essential to feeding a planet of 7 billion people. Why? They're nutritious, better for the environment than other protein sources and can generate jobs, according to the FAO.

"Insects are pretty much untapped for their potential for food, and especially for feed," Eva Muller, director of FAO's Forest Economics, Policy and Products Division, said in a statement.

Of course, 2 billion people worldwide already enjoy insects with gusto — in Africa, Asia, Latin America and Australia. As The Salt previously reported, some efforts have focused on "grow-your-own-insect" kits as a form of emergency food aid for African refugees. Among the most popular of the 1,900 species consumed are beetles, caterpillars, wasps, ants, grasshoppers, locusts and crickets. But rich nations have turned up their noses at them, and the FAO says it's high time for that to change.

There are some signs that investors are warming to insect farming, as climate change has a lot of people rethinking where we get our protein. And insects are now looking like a pretty appealing alternative: They emit considerably less greenhouse gases and waste than other animals, they require little to no land, and many species can consume waste products like animal blood, which means we wouldn't need to produce feed (like soybeans or corn) especially for them.

And if you want to talk about feed efficiency, insects use just 2 pounds of feed to produce 1 pound of meat. Cattle, at the other end of the spectrum, require 8 pounds of feed to produce 1 pound of beef, the FAO says. Locusts beat out beef when it comes to essential nutrients like iron, too: between 8 and 20 milligrams per 100 grams of dry weight of locusts, compared with 6 milligrams per 100 grams of dry weight of beef.

In addition to bugs to feed people, the FAO is optimistic about opportunities to raise insects to feed to animals. As we reported last year, fly farming in South Africa is starting to get off the ground. Just last week, entrepreneur Jason Drew, who's raising flies to feed salmon and chicken, won the highly competitive U.N. Innovation Prize for Africa.

So why haven't we seen a big insect farming boom yet?

There's the disgust factor, for one thing. But there are also big regulatory hurdles: In many countries, the FAO says, regulations on producing insects for food aren't very clear. (Ironically, in the U.S., regulations allow for a certain amount of insect bits to make it into our food, but they don't cover insects as the main meal, according to the FAO.)

Then there are all sorts of food safety concerns. For example, if you were to raise flies on animal blood — a normal source of food for the insects — what happens if you then feed the flies to chickens meant for human consumption? The FAO is calling for more research to untangle such questions.

But FAO says the future is bright for edible insects. "Although it will require considerable convincing to reverse [feelings of disgust], it is not an impossible feat," the report states. British artists seem to agree: A recent exhibition at the U.K.'s Wellcome Collection showcased 3-D printing demos of "possible novel insect foods" of the future.

Last year, almost the entire Michigan apple crop was lost because of 80-degree days in March and then some freezing April nights. This year, the apples are back, but everything always depends on the weather. The state was under a freeze warning Sunday night — a scary prospect if you're an apple grower and your trees have just come into bloom.

Tim Boles and his agribusiness colleague Case DeYoung were driving to work one morning in late April 2012 after a killing frost had hit the apple orchards in The Ridge, a region of ridges and rolling valleys in the west-central part of the state close to Lake Michigan. They stopped at a high point and knew things were bad when they saw the helicopters hovering, hoping to push down a warmer layer of air.

"Some of the farmers from the area had gone down south and brought back smudge pots to generate some warm air and smoke to try and help warm the trees," Boles says. "So you had the sound of the helicopters — thump, thump, thump — and the smoke and the rising sun, and Case and I both remarked that it was like Apocalypse Now."

Suanne Shoemaker and her family's farm on Six Mile Road could only harvest 1 percent of their 30 acres of apples in 2012. But this year, "It looks great," Shoemaker says. "We're all excited, all the growers are. Everybody's happy around here this year."

Every Wednesday morning during apple season, growers show up at a local restaurant at 7 a.m. for a free breakfast (paid for by one of the farm chemical companies) and a briefing from Amy Irish-Brown, an extension educator from Michigan State University. She talks about spores, beetles, aphids and especially the weather.

"It's surprising how dry it is, and that's partly because we haven't had any rain but also because relative humidity has been extremely low. That's what's drying things out fairly quickly," she says. She wants the growers to keep this in mind as they're planting new trees. And she leaves them with a caution about the freeze coming on the night of Mother's Day.

As it turned out, there was frost on The Ridge — just at full bloom time. But, in an email, Irish-Brown says, "We should be OK. Perhaps a little damage but still have the potential for a full apple crop."

For decades, scientists have believed our ancestors took up farming some 12,000 years ago because it was a more efficient way of getting food. But a growing body of research suggests that wasn't the case at all.

"We know that the first farmers were shorter, they were more prone to disease than the hunter-gatherers," says Samuel Bowles, the director of the Behavioral Sciences Program at the Santa Fe Institute in New Mexico, describing recent archaeological research.

Bowles' own work has found that the earliest farmers expended way more calories in growing food than they did in hunting and gathering it. "When you add it all up, it was not a bargain," says Bowles.

So why farm? Bowles lays out his theory in a new study in the journal Proceedings of the National Academy of Sciences. The reasons are complex, but they revolve around the concept of private property.

Think of these early farmers as prehistoric suburbanites of sorts. The first farmers emerged in less than a dozen spots in Asia and South America. Bowles says they were already living in small villages. They owned their houses and other objects, like jewelry, boats and a range of tools, including fishing gear.

They still hunted and foraged, but they didn't have to venture far for food: They had picked fertile places to settle down, and so food was abundant. For example, one group in what is present-day Iraq lived close to a gazelle migration route. During migration season, it was easy pickings — they killed more animals than they could eat in one sitting. They also harvested more grain from wild plants than they knew what to do with. And so, they built "pantries" — structures where they could store the extra food.

These societies had seen the value of owning stuff — they were already recognizing "private property rights," says Bowles. That's a big transition from nomadic cultures, which by and large don't recognize individual property. All resources, even in modern day hunter-gatherers, are shared with everyone in the community.

But the good times didn't last forever in these prehistoric villages. In some places, the weather changed for the worse. In other places, the animals either changed their migratory route or dwindled in numbers.

At this point, Bowles says these communities had a choice: They could either return to a nomadic lifestyle, or stay put in the villages they had built and "use their knowledge of seeds and how they grow, and the possibility of domesticating animals."

Stay put, they did. And over time, they also grew in numbers. Why? Because the early farmers had one advantage over their nomadic cousins: Raising kids is much less work when one isn't constantly on the move. And so, they could and did have more children.

In other words, Bowles thinks early cultures that recognized private property gave people a reason to plant roots in one place and invent farming — and stick with it despite its initial failures.

Bowles admits that this is just an informed theory. But to test it, he and his colleague Jung-Kyoo Choi built a mathematical model that simulated social and environmental conditions among early hunter-gatherers. In this simulation, farming evolved only in groups that recognized private property rights. What's more, in the simulations, once farming met private property, the two reinforced each other and spread through the world.

Bowles' theory offers a more nuanced explanation that ties together cultural, environmental and technological realities facing those first farmers, says Ian Kuijt, an anthropologist at the University of Notre Dame who specializes in the origins of agriculture.

But, he says, the challenge is to figure out who owned the property back then and how they ran it. "Was it owned by one individual?" Kuijt says. "Was it a mother and father and their children? ... Does it represent community or village property?"