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Just Desserts: Artificial Sweeteners Linked to Weight Gain

New research indicates that saccharin and other sugar substitutes may not be such a sweet deal for weight watchers

 
ARE DIET DRINKS FATTENING?: A new study adds to the growing body of evidence that artificial sweeteners may add, rather than trim weight.

You know those no-guilt diet drinks you chug by the gallon, and the fake sugar you dump in your coffee to stay trim? Bad news: a new study suggests that artificial sweeteners may actually make it harder to control your weight.

Psychologists at Purdue University's Ingestive Behavior Research Center report that nine rats given yogurt sweetened with no-cal saccharin ended up eating more and gaining more weight and body fat than eight fellow rodents given yogurt containing plain old glucose (a simple sugar with about 15 calories per teaspoon, the same as table sugar).

Study authors Susan Swithers and Terry Davidson speculate the reason is that the faux sweetener messes with the brain, fooling it into revving up the body's metabolism in anticipation of a never-to-come calorie load.

Typically, they say, the taste buds, sensing something sweet, signal the brain to prep the digestive system to gear up for a caloric onslaught; when the expected sugar jolt (extra calories) fails to materialize, the body gets rattled and has trouble bouncing back and regulating appetite when other food is available. As a result, the rats eat more or expend less energy than they would have had they had the real thing.

"The data clearly indicate that consuming a food sweetened with no-calorie saccharin can lead to greater body-weight gain and adiposity [fat] than would consuming the same food sweetened with a higher-calorie sugar," the authors write in the journal Behavioral Neuroscience. They say that other artificial sweeteners—aspartame, sucralose and acesulfame—could have a similar effect.

The researchers note that the findings jive with other emerging evidence—including a study published last month in the American Heart Association's journal, Circulation—that shows people who down diet drinks are at a higher risk for obesity and metabolic syndrome (a medley of medical problems such as abdominal fat, high blood pressure and insulin resistance that puts people at risk for heart disease and diabetes).

They acknowledge, however, that more research is needed. After all, just because this counterintuitive effect may occur in rats does not necessarily mean it also could be happening in humans. Still, let it serve as a warning to anyone who may have a false sense of security that artificial sweeteners are all it takes to be fit and healthy.

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McCain's Beef with Bears?—Pork

The presidential wannabe scoffs at pouring millions into studying grizzly bear DNA, but scientists say it's key to preserving the species

 
GRIZZLY AND CUB: Since 1975 Montana grizzly bears have been listed as a threatened species by the U.S. government.

Republican presidential hopeful John McCain is a well-known critic of frivolous government spending otherwise known as pork: those pricey projects that legislators routinely—and surreptitiously—slip into appropriations packages to benefit their own districts and bring them coveted votes. But scientists charge that an important study of grizzly bear DNA has gotten caught in the crosshairs as the veteran Arizona lawmaker attempts to showcase his creds as a crusader against wasteful government spending.

It is unclear why McCain, who has taken a firm stand on some other environmental issues—he believes more needs to be done to curtail global warming—considers the research to be a waste of time and money, and his press office did not respond to repeated e-mails and phone calls for comment. Yet, he is apparently so "outraged" that he takes a dig at it in a campaign TV spot in which an announcer declares:

"233 million for a bridge to nowhere. Outrageous… Three million to study the DNA of bears in Montana. Unbelievable… A million dollars for a Woodstock Museum—in a bill sponsored by Hillary Clinton. Predictable… Who has the guts to stand up to wasteful government spending? One man. John McCain."

Currently the front-runner for the GOP nod, McCain also hits the research in speeches on the stump, cracking jokes about bear paternity tests and criminal investigations. "I don't know if it was a paternity issue or criminal, but it was a waste of money," McCain railed last month during a campaign stop in Clawson, Mich. Scientists, however, are not amused: They insist that the study is not only worth every penny but that the $3-million price tag cited in the ad is, in a word, wrong.

In fact, Congress over the past five years has forked over a total of $4.8 million to study the genetic material of Montana's grizzly bears, according to Katherine Kendall, a research biologist at the U.S. Geological Survey (USGS). Kendall heads the Northern Divide Grizzly Bear Project, which is aimed at obtaining the first accurate population estimate of grizzlies living in the Northern Continental Divide Ecosystem—eight million acres of land in northwestern Montana that encompasses Glacier National Park and the Bob Marshall Wilderness Complex.

"This is not pork barrel at all," says Richard Mace, a research biologist with Montana Fish, Wildlife & Parks (FWP). "We have a federal law called the Endangered Species Act and [under this law] the federal government is supposed to help identify and conserve threatened species."

The grizzly has been listed as a threatened species since 1975 and scientists say that it is essential to get a handle on the population to preserve it. But, according to Kendall, until the feds decided to invest in this grizzly bear DNA study, researchers lacked the funds to conduct research at the scale necessary to get a reliable measure.

In 2002 Kendall assembled a scientific panel with representatives from the USGS, U.S. Fish and Wildlife Service and FWP, along with other scientific and environmental organizations to determine the best way to measure the remaining grizzly population of the Northern Continental Divide Ecosystem. It recommended setting up barbed wire hair-snagging stations to painlessly pluck fur from passing bears that would be used for DNA fingerprinting, a technique employed to distinguish individuals of the same species by the differences in their genetic material. This is the only way to accurately estimate population in such heavily forested terrain, where bears are difficult to spot, says Chris Servheen, a grizzly expert with the U.S. Fish and Wildlife Service.

In response, the USGS set aside $250,000 to launch the Northern Divide Grizzly Bear Project; the next year, Congress stepped in to provide additional funding, and from 2003 to 2007 appropriated $4.8 million to the effort, Kendall says.

She notes that her team of 250 scientists and researchers set up hair-snag stations at thousands of locations throughout the grizzly habitat, some as far as 30 miles (50 kilometers) from the nearest road. These wire setups do not harm the bears in any way, Servheen says: "It's no more than running a comb through your hair."

The team collected 34,000 samples of bear hair over a 14-week period in 2004, which it sent over the border to the Wildlife Genetics International laboratory in Nelson, British Columbia. By extracting and analyzing DNA in the strands, researchers were able to pinpoint the species (grizzly or black bear), gender, and individual identity of host bears. It took two years to analyze the large swath of samples and another to compile the data and conduct statistical analyses to estimate the size, distribution and genetic structure of the population as well as summarize the findings, which Kendall says she hopes to publish in a science journal by summer. (She refuses to reveal the results prior to publication.)

But numbers are only part of the story. Scientists say they also have to figure out how the population is changing to determine how to protect it. Toward that end, the Montana state government four years ago launched a $250,000 per annum effort to monitor grizzly population trends (separate from, but complementary to Kendall's study on population size), according to Mace, who is in charge of that project.

"There are no answers yet," he says, noting that it is too early to tell whether the population is increasing, decreasing or if it remains unchanged since 2004. But researchers are optimistic they will be able to fashion effective preservation measures once they have a better idea of [to vary] the population size—thanks to Kendall's study—and a solid understanding of trends.

Still, for many Americans who have never seen and probably never will see a grizzly bear, the question remains: Why should one bear population merit millions in taxpayer money?

The reason, grizzly expert Servheen says: the bears are a threatened species. He estimates that only about 1,500 still reside in the 48 contiguous states, compared with some 50,000 before the arrival of Europeans in the 15th century (a 97 percent population decline). The once far-reaching grizzly habitat, which stretched from the Mississippi River to California and ranged north to south from Alaska to Mexico, is today restricted to four western states: Wyoming, Idaho, Montana, and Washington. In these states, only two populations—those living in and around Yellowstone National Park and in the Northern Continental Divide Ecosystem—number more than 50 bears and offer hope for long-term viability, Servheen says.

So is forking over huge chunks of change to protect grizzly bears "unbelievable"—or a joke—as McCain charges?

No way, scientists and environmentalists say. Protecting wildlife is expensive, but grizzlies are priceless, says Louisa Willcox, director of the Wild Bears Project for the National Resources Defense Council. "Grizzly bears are a symbol of our frontier past—of untamed wilderness," she says. "Lewis and Clark saw them eating buffalo carcasses on the American plains."

Not only are grizzlies "treasures of United States history," Servheen says, but they help us understand how effective our conservation efforts are. Despite their ferocious reputation, he notes, grizzlies are exquisitely sensitive to human activity and can only live on the wildest tracts of land. "They are an indicator of the health of ecosystems," he says, and they emblematize "the preservation of wilderness, which is becoming rarer every day."

Biofuels Are Bad for Feeding People and Combating Climate Change

By displacing agriculture for food—and causing more land clearing—biofuels are bad for hungry people and the environment

rainforest-burned-to-plant-palm
BAD BIOFUEL: Clearing rainforest to plant palms for oil, like the one pictured here, is a major emitter of the greenhouse gases that cause climate change.

Converting corn to ethanol in Iowa not only leads to clearing more of the Amazonian rainforest, researchers report in a pair of new studies in Science, but also would do little to slow global warming—and often make it worse.

"Prior analyses made an accounting error," says one study's lead author, Tim Searchinger, an agricultural expert at Princeton University. "There is a huge imbalance between the carbon lost by plowing up a hectare [2.47 acres] of forest or grassland from the benefit you get from biofuels."

Growing plants store carbon in their roots, shoots and leaves. As a result, the world's plants and the soil in which they grow contain nearly three times as much carbon as the entire atmosphere. "I know when I look at a tree that half the dry weight of it is carbon," says ecologist David Tilman of the University of Minnesota, coauthor of the other study which examined the "carbon debt" embedded in any biofuel. "That's going to end up as carbon dioxide in the atmosphere when you cut it down."

By turning crops such as corn, sugarcane and palm oil into biofuels—whether ethanol, biodiesel, or something else—proponents hope to reap the benefits of the carbon soaked up as the plants grow to offset the carbon dioxide (CO2) emitted when the resulting fuel is burned. But whether biofuels emit more or less CO2 than gasoline depends on what the land they were grown on was previously used for, both studies show.

Tilman and his colleagues examined the overall CO2 released when land use changes occur. Converting the grasslands of the U.S. to grow corn results in excess greenhouse gas emissions of 134 metric tons of CO2 per hectare—a debt that would take 93 years to repay by replacing gasoline with corn-based ethanol. And converting jungles to palm plantations or tropical rainforest to soy fields would take centuries to pay back their carbon debts. "Any biofuel that causes land clearing is likely to increase global warming," says ecologist Joseph Fargione of The Nature Conservancy, lead author of the second study. "It takes decades to centuries to repay the carbon debt that is created from clearing land."

Diverting food crops into fuel production leads to ever more land clearing as well. Ethanol demand in the U.S., for example, has caused some farmers to plant more corn and less soy. This has driven up soy prices causing farmers in Brazil to clear more Amazon rainforest land to plant valuable soy, Searchinger's study notes. Because a soy field contains far less carbon than a rainforest, the greenhouse gas benefit of the original ethanol is wiped out. "Corn-based ethanol, instead of producing a 20 percent savings [in greenhouse gas emissions], nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years," the researchers write. "We can't get to a result with corn ethanol where we can generate greenhouse gas benefits," Searchinger adds.

Turning food into fuel also has the unintended consequence of driving up food prices, reducing the access of the neediest populations to grains and meat. "It's equivalent to saying we will try to reduce greenhouse gases by reducing food consumption," Searchinger says. "Unfortunately, a lot of that comes from the world's poorest people."

"We are converting their food into our fuel," Tilman notes. " The typical driver of an SUV spends as much on fuel in a month as the poorer third of the world spend on food."

The studies do find some benefit from biofuels but only when planted on agricultural land too dry or degraded for food production or significant tree or plant growth and only when derived from native plants, such as a mix of prairie grasses in the U.S. Midwest. Or such fuels can be made from waste: corn stalks, leftover wood from timber production or even city garbage.

But that will not slake a significant portion of the growing thirst for transportation fuels. "If we convert every corn kernel grown today in the U.S. to ethanol we offset just 12 percent of our gasoline use," notes ecologist Jason Hill of the University of Minnesota. "The real benefit to these advanced biofuels may not be in displacement of fossil fuels but in the building up of carbon stores in the soil."

Of course, there is another reason for biofuels: energy independence. "Biofuels like ethanol are the only tool readily available that can begin to address the challenge of energy security," Bob Dinneen, president of industry group the Renewable Fuels Association said in a statement. "The alternative is to continue to exploit increasingly costlier fossil fuels for which the environmental price tag will be great."

But the environmental price tag of biofuels now joins the ranks of other, cheaper domestic fuel sources—such as coal-to-liquid fuel—as major sources of globe-warming pollution as well as unintended social consequences. As a result, 10 prominent scientists have written a letter to President Bush and other government leaders urging them to "shape policies to assure that government incentives for biofuels do not increase global warming."

"We shouldn't abandon biofuels," Searchinger says. But "you don't solve global warming by going in the wrong direction."

Fact or Fiction?: People Only Use 10 Percent Of Their Brains

What's the matter with only exploiting a portion of our gray matter?

The human brain is complex. It enables concertos to be composed, manifestos made, and equations solved elegantly. It's also the wellspring of feelings, behaviors, experiences and the repository of memory. So it's no surprise that the brain remains a mystery.

Adding to that mystery is the contention that humans "only" employ 10 percent of their brain. If only regular folk could tap that other 90 percent they too could become savants who remember pi to the 20,000th decimal place or perhaps even a psychic.

Though an alluring idea, the "ten percent myth" is so wrong it is almost laughable, says neurologist Barry Gordon at Johns Hopkins University in Baltimore. While there’s no definitive culprit to the beginning of this legend, the notion has been linked to the American psychologist and author William James, who argued in The Energies of Men that “We are making use of only a small part of our possible mental and physical resources.” It's also been linked to Albert Einstein, who supposedly used it to explain his cosmic intellect.

The myth's durability, Gordon says, stems from people's conceptions about their own brains: their own shortcomings demonstrate the existence of untapped gray matter. This is false. What is correct however, is that at certain moments in anyone's life, such as when we are simply sitting and thinking, we may be using only 10 percent of our brain.

"It turns out though, that we use virtually every part of the brain, and that [most of] the brain is active almost all the time," Gordon adds. "Let's put it this way, the brain represents three percent of the body's weight, and uses 20 percent of the body's energy."

The average human brain weighs about three pounds and is comprised of the hefty cerebrum, which is the largest portion of the brain that performs all higher cognitive functions; the cerebellum, which controls coordination of movement and balance; and the brainstem, which maintains unconscious functions like breathing. The majority of the energy used by the brain powers the rapid firing of neurons communicating with each other. Scientists think it is such neurons firing and connecting to each other that gives rise to all the functions the brain produces. The rest of the brain’s energy is used for controlling other activities, both unconscious activities, such as heart rate, and conscious, such as driving a car.

While it's true that at any given moment all of the brain's regions are not concurrently firing, brain researchers using brain imaging technologies have shown that, like the body's muscles, most are used during a 24-hour period. "Evidence would show over a day you use 100 percent of the brain," says neurologist John Henley at the Mayo Clinic in Rochester, Minn. Even in sleep, areas such as the frontal cortex, which controls things like higher level thinking and self awareness, or the somatasensory areas, which helps people sense their surroundings, are active, Henley explains.

Take the simple act of pouring coffee in the morning. Walking towards the coffeepot, reaching for it, filling the mug with the brew, even leaving extra room for cream, the occipital and parietal lobes, motor-sensory and sensory-motor cortices, basal ganglia, cerebellum, and frontal lobes all activate. A lightning storm of neuron activity occurs almost across the entire brain in the time span of a few seconds.

"This isn't to say that if the brain were damaged that you wouldn't be able to perform daily duties," Henley continues. "There are people who have injured their brains or had parts of it removed who still live fairly normal lives, but that is because the brain has a way of compensating and making sure that what's left, takes over the activity."

Being able to map the brain's various regions and functions is part and parcel of understanding the possible side effects should a region begin to fail. Experts know that neurons that perform similar functions tend to cluster together. For example, neurons that control the thumb's movement are arranged next to those that control the forefinger. Thus, when undertaking brain surgery, neurosurgeons carefully avoid the brains neural clusters related to vision, hearing and movement, enabling the brain to maintain as much of its functions as possible.

What's not understood is how clusters of neurons from the diverse regions of the brain collaborate to form consciousness. So far, there's no evidence that there is one site for consciousness, which leads experts to believe that it is truly a collective neural effort, if not experience. Another mystery hidden within our crinkled cortices is that out of all of the brain's cells, 10 percent are neurons and 90 percent are glial cells, which encapsulate and support neurons and remain largely unknown. Ultimately, it's not that we use 10 percent of our brains, merely that we only understand about 10 percent of how it functions.

Fat? No Food for You!

Mississippi lawmakers introduce bill that would ban restaurants from serving portly patrons

 
NO FAT PEOPLE SERVED HERE: Mississippi legislation would prohibit restaurants there from serving obese customers.

You're big, bulky—and hungry. So you lumber into a restaurant to get a bite. You scan the menu for a tasty meal, but when it comes time to order the waiter refuses to serve you. The reason? You're too fat. Sound outrageous? You may want to steer clear of Mississippi, where legislation was recently introduced that would ban restaurants from serving proportion-challenged patrons.

We kid you not. The controversial measure (state House Bill 282) would prohibit eateries from serving food to "any person who is obese based on criteria prescribed by the state health department." The department would monitor compliance and have the power to revoke violators' permits. (Pity the poor waiter with the thankless task of denying corpulent customers service, leaving them with the humiliating dilemma of either twiddling their thumbs as their less hefty chums chow down or slinking (storming?) out and slogging to a supermarket or over the state line for sustenance.)

Sponsors of the legislation insist that it was designed to spark discussion on ways to get a handle on obesity: More than 30 percent of Mississippi's adults are considered obese, giving the Magnolia State--where fried chicken and other greasy fare rule--the distinction of being the nation's first in fatness, according to a 2007 study by the Trust for America's Health, a Washington, D.C.–based research group that focuses on disease prevention.

"I was trying to shed a little light on the number one health problem in Mississippi," co-sponsor Republican Rep. John Read of Gautier, a former pharmaceutical company sales representative, told the Associated Press, acknowledging that at five feet, 11 inches (1.8 meters) and 230 pounds (104 kilograms), he might get the restaurant boot under his own bill.

People, both chubby and thin, immediately blasted the proposal. Physicians called it insane, saying it would do nothing to help plump patients pare down to healthier weights. The rotund rights lobby agreed, charging that it was discriminatory and arbitrary. "We as Americans have made substantial progress in race and gender relations. Unfortunately, our progress hasn't extended to our country's uneasy relationship with fat people," Paul McAleer, president of the Coalition of Fat Rights Activists, said in a statement.

And the restaurant industry, which stands to lose many a coveted and loyal customer, was beside itself.

"This is the latest example of food cops run amok. Are waiters supposed to carry scales around the restaurant and weigh every customer? Give me a break," J. Justin Wilson, a senior research analyst at The Center for Consumer Freedom, which represents the restaurant and food service industry, said in a statement. "What's next? Will waitresses soon be expected to make sure we eat all our veggies?"

More helpful in the battle of bulge, say critics: programs directed at getting to the core of the problem, such as a law passed in Mississippi last year that requires kids in kindergarten through eighth grade to receive at least 150 minutes of physical education and 45 minutes of health ed instruction weekly; until then, gym had been optional.

But lest you're not a skinny-minny and worry you may starve should you travel to Mississippi—fear not: state Rep. Steve Holland, the Democratic chairman of the House Public Health and Human Services Committee, pronounced the controversial bill "dead on arrival at my desk." In other words, it will never even make it out of committee and onto the floor of the legislature for a vote. "While I appreciate the efforts of my fellow House members to help curb the obesity problem in Mississippi,'' he said, "this is totally the wrong approach.''

That'll teach the (anti-) fat cats to stick their (tape) measures where they don't belong.

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