The average American consumes about 22 teaspoons (355 calories) of added sugar a day, according to a report released yesterday by the American Heart Association (AHA). That amount should be cut down to a maximum of six teaspoons (100 calories) a day for women and nine teaspoons (150 calories) for men, the group recommends.

"For the first time we've created specific recommendations about the amount of sugars that can be consumed in a heart-healthy diet," lead report author Rachel Johnson, of the University of Vermont in Burlington, told Reuters.

A diet high in added sugar—the sort that makes up the sanguine syrups in sodas and saccharine snacks, rather than the natural sugars found, for instance, in whole fruits—could lead to obesity and cardiovascular disease, as well as diabetes and a host of other illnesses, according to the research compiled by the American Heart Association. And if Americans slim down, Johnson and her colleagues note, the country could shed billions of dollars in health care costs.

One out of every nine people now receives food stamps in the U.S. And two thirds of Americans are either overweight or obese. A new scientific study links these startling figures and suggests that food stamps may actually be a risk factor for obesity.

Participants in the U.S. Food Stamp Program have, on average, a body mass index (BMI) more than one point higher than nonusers, according to research published in the current issue of Economics and Human Biology. This difference was especially high for women: those buying their food with stamps carried around an average of 5.8 pounds more body weight. The researchers also found that BMI rose higher the longer participants received the stamps.

A large portion of the human genome (approximately 98 percent) does not encode genes. Long thought to be "junk DNA," these portions, researchers continue to learn, can play a role in genetic activity and, subsequently, in health and sickness. According to researchers at the German Institute of Human Nutrition, one such junk fragment might actually prevent symptoms of type 2 diabetes in obese mammals.

Type 2 diabetes is the most common form of diabetes, accounting for about 90 to 95 percent of all cases in the U.S., according to the National Institute of Health, and primarily affects overweight people.  These recent findings, published in PLoS Genetics, identify a likely contributor to obesity-linked type 2 diabetes. In particular, the researchers found that obese mice lacking a particular fragment of noncoding DNA called a retrotransposon had type 2 diabetes-like symptoms.

A new study confirms that calorie-burning tissue called brown fat once believed to be present only in infants is actually relatively common in adults – at least in slender ones.

Study co-author Ronald Kahn, a cellular and molecular physiologist at the Joslin Diabetes Center in Boston, Mass., says the finding adds to growing evidence that "brown fat helps people stay slim."

Unlike white fat, which stores excess calories, brown fat burns calories to generate heat – and scientists have long known that newborn humans (as well as baby and adult rats, mice and other mammals) have it to keep them warm. But researchers believed that most if not all of it was shed after infancy, because its job was done.

New research pinpointing the link between the body clock and metabolism may pave the way for scientists to treat an array of health problems, ranging from diabetes to sleep disorders.

In humans and other mammals, circadian rhythms, or the body clock, control everything from sleep to hormones. It is present – albeit less sophisticated – in life forms all the way down to plants and yeasts to ensure that important functions, such as cell regeneration, occur at the optimal time of the 24-hour day-night cycle. (It's also to blame for jet lag.) Scientists have long suspected that it is connected with metabolism (the way our bodies use energy), but they weren't sure exactly how.

In an attempt to unlock this molecular mystery, Joe Bass, an assistant professor of neurobiology and physiology at Northwestern University in Evanston, Ill., and colleagues wanted to see how the two functions might be related in mammals. They placed the mice – some with normal circadian rhythms and others whose rhythms had been disrupted – in complete darkness for 48 hours (in an effort to confuse normal body cycles). Their findings, published today in an online edition of Science: levels of the enzyme Nicotinamide adenine dinucleotide (NAD+), known to play a key role in metabolism, were low and constant in the mice with disrupted clocks but, even in perpetual darkness, levels of the enzyme in unaltered animals fluctuated in tune with daily cycles.

Think firefighters and emergency medical technicians (EMTs) are in tip-top shape? Not necessarily, according to a new study published today in the journal Obesity. Researchers found that 77 percent of emergency responder recruits in Boston are either overweight or obese, a result they say is likely similar in other cities and towns.

"Both firefighters and EMTs have pretty significant risks of cardiovascular events [such as heart attacks] as a result of the physical demands of the job…They are also at risk for musculoskeletal injuries," says study co-author Antonios Tsismenakis, a medical student at Boston University School of Medicine. Carrying additional pounds magnifies these risks, he adds. "If an emergency responder goes down," he says, "that has potential implications for his or her colleagues, and for you and me."

Sleep apnea, a disorder that can cause sufferers to temporarily stop breathing while snoozing, has long been associated with obesity. Paradoxical new findings suggest an ironic benefit: the worse the disease gets, the more calories patients burn.

"It's something of a silver lining," says Eric Kezirian, director of the division of sleep surgery at the University of California, San Francisco, whose research appears in today's Archives of Otolaryngology-Head & Neck Surgery. "It's not hurting in certain areas, but may be hurting in other areas."

Researchers have identified six genes that may play a role in our appetite and, as a result, in whether we're plump or thin. They report in Nature Genetics that the genes appear to affect brain activity that controls how much we eat, indicating that obesity, at least in part, may stem from behavior passed on from one generation to the next.

The GIANT Consortium, an international group of scientists from over 60 institutions worldwide, compared the body mass index (BMI), a standard measure of body fat, with the genetic makeup of 90,000 people of European ancestry. Their findings: that slimmer folks had different versions of the six genes than their flabbier compeers.

Study co-author Elizabeth Speliotes, an internist at Massachusetts General Hospital, says the genes control activity in the brain's cortex (involved in decision making) and hypothalamus (which regulates appetite), indicating that the brain is a key factor in weight. But she notes that it's unclear exactly how the genes may affect hunger.

An experimental drug that works much like an ingredient in red wine and grapes kept rodents from getting fat and increased their endurance. Researchers say the drug, SIRT1720, also lowered glucose levels — good news for a human version of the medicine being developed to treat diabetes.

The findings, published in the journal Cell Metabolism, show that mice fed a high-fat diet for 10 weeks who were given 100-milligram or 500-milligram doses of the med stayed svelte; animals on the same diet that didn't receive the drug packed on the pounds. The 10 medicated mice also ran twice as long as normal rodents.

Now here's a surprise: most cereals marketed to kids are chock full o' sugar and salt but don't contain much fiber. Wondering which ones are the best of the lot? Whether any are really the breakfast of champions—or just sugar-saturated lucky charms for the little laddies? Good news: Consumer Reports has analyzed the nutritional value of cereals targeted to children. The results, published in the mag's November issue: only four of 27 brands tested were rated as "very good," based on their (low) sugar, (relatively high) fiber and calcium content; the rest were "fair" to "good."

"If you're going to buy one of these kids' cereals," Consumer Reports says, "we recommend you pick one that is rated very good."