STOCKHOLM » Shopping for oatmeal, Helena Bergstrom, 37, admitted that she was flummoxed by the label on the blue box reading, “;Climate declared: .87 kg CO2 per kg of product.”;

“;Right now, I don't know what this means,”; said Bergstrom, a pharmaceutical company employee.

But if a new experiment here succeeds, she and millions of other Swedes will soon find out. New labels listing the carbon dioxide emissions associated with the production of foods, from whole wheat pasta to fast food burgers, are appearing on some grocery items and restaurant menus around the country.

People who live to eat might dismiss this as silly. But changing one's diet can be as effective in reducing emissions of climate-changing gases as changing the car one drives or doing away with the clothes dryer, scientific experts say.

“;We're the first to do it, and it's a new way of thinking for us,”; said Ulf Bohman, head of the Nutrition Department at the Swedish National Food Administration, which was given the task last year of creating new food guidelines giving equal weight to climate and health. “;We're used to thinking about safety and nutrition as one thing and environmental as another.”;

Some of the proposed new dietary guidelines, released over the summer, may seem startling to the uninitiated. They recommend that Swedes favor carrots over cucumbers and tomatoes, for example. (Unlike carrots, the latter two must be grown in heated greenhouses here, consuming energy.)

They are not counseled to eat more fish, despite the health benefits, because Europe's stocks are depleted.

And somewhat less surprisingly, they are advised to substitute beans or chicken for red meat, in view of the heavy greenhouse gas emissions associated with raising cattle.

“;For consumers, it's hard,”; Bohman acknowledged. “;You are getting environmental advice that you have to coordinate with, 'How can I eat healthier?”;'

Many Swedish diners say it is just too much to ask. “;I wish I could say that the information has made me change what I eat, but it hasn't,”; said Richard Lalander, 27, who was eating a Max hamburger (1.7 kilograms of carbon dioxide emissions) in the shadow of a menu board revealing that a chicken sandwich (0.4 kilograms) would have been better for the planet.

Yet if the new food guidelines were religiously heeded, some experts say, Sweden could cut its emissions from food production by 20 to 50 percent.

An estimated 25 percent of the emissions produced by people in industrialized nations can be traced to the food they eat, according to recent research here. And foods vary enormously in the emissions released in their production.

While today's American or European shoppers may be well versed in checking for nutrients, calories or fat content, they often have little idea of whether eating tomatoes, chicken or rice is good or bad for the climate.

Complicating matters, the emissions impact of, say, a carrot, can vary by a factor of 10, depending how and where it is grown.

Earlier studies of food emissions focused on the high environmental costs of transporting food and raising cattle. But more nuanced research shows that the emissions depend on many factors, including the type of soil used to grow the food and whether a dairy farmer uses local rapeseed or imported soy for cattle feed.

Business groups, farming cooperatives and organic labeling programs as well as the government have gamely come up with coordinated ways to identify food choices.

Max, Sweden's largest homegrown chain of burger restaurants, puts emissions calculations next to each item on its menu boards. Lantmannen, Sweden's largest farming group, has begun placing precise labels on some categories of foods in grocery stores, including chicken, oatmeal, barley and pasta.

Consumers who pay attention may learn that emissions generated by growing the nation's most popular grain, rice, are two to three times those of little-used barley, for example.

Some producers argue that the new programs are overly complex and threaten profits. The dietary recommendations, which are being circulated for comment not just in Sweden but across the European Union, have been attacked by the Continent's meat industry, Norwegian salmon farmers and Malaysian palm oil growers, to name a few.

“;This is trial and error; we're still trying to see what works,”; Bohman said.

Next year, KRAV, Scandinavia's main organic certification program, will start requiring farmers to convert to low-emissions techniques if they want to display its coveted seal on products, meaning that most greenhouse tomatoes can no longer be called organic.

Those standards have stirred some protests. “;There are farmers who are happy and farmers who say they are being ruined,”; said Johan Cejie, manager of climate issues for KRAV.

For example, he said, farmers with high concentrations of peat soil on their property may no longer be able to grow carrots, since plowing peat releases huge amounts of carbon dioxide; to get the organic label, they may have to switch to feed crops that require no plowing.

Next year, KRAV will require hothouses to use biofuels for heating. Dairy farms will have to obtain at least 70 percent of the food for their herds locally; many previously imported cheap soy from Brazil, generating transport emissions and damaging the rain forest as trees were cleared to make way for farmland.

The Swedish effort grew out of a 2005 study by Sweden's national environmental agency on how personal consumption generates emissions. Researchers found that 25 percent of national per capita emissions - two metric tons per year - was attributable to eating.

The government realized that encouraging a diet that tilted more toward chicken or vegetables and educating farmers on lowering emissions generally could have an enormous impact.

Sweden has been a world leader in finding new ways to reduce emissions. It has vowed to eliminate the use of fossil fuel for electricity by 2020 and cars that run on gasoline by 2030.

To arrive at numbers for their company's first carbon dioxide labels, scientists at Lantmannen analyzed life cycles of 20 products. These take into account emissions generated by fertilizer, fuel for harvesting machinery, packaging and transport.

They decided to examine one representative product in each category - say, pasta - rather than performing analyses for fusilli versus penne, or one brand versus another. “;Every climate declaration is hugely time-intensive,”; said Claes Johansson, Lantmannen's director of sustainability.

A new generation of Swedish business leaders is stepping up to the climate challenge. Richard Bergfors, president of Max, his family's burger chain, voluntarily hired a consultant to calculate its carbon footprint; 75 percent was created by its meat.

“;We decided to be honest and put it all out there and say we'll do everything we can to reduce,”; said Bergfors, 40. In addition to putting emissions data on the menu, Max eliminated boxes from its children's meals, installed low-energy LED lights and pays for wind-generated electricity.

Since the emissions counts started appearing on the menu, sales of climate-friendly items have risen 20 percent. Still, plenty of people head to a burger restaurant lusting only for a burger.

Kristian Eriksson, 26, an information technology specialist, looked embarrassed when asked about the burger he was eating at an outdoor table. “;You feel guilty picking red meat,”; he said.