THURSDAY, Sept. 20 (HealthDay News) -- Scientists served M&Ms to rats in an experiment that showed the brain can't resist sweet and fatty foods.

The University of Michigan researchers said the urge to overeat tasty treats comes from an unexpected area of the brain called the neostriatum, which produces an opium-like chemical that enhances such desire and may be partly responsible for overeating among people.

"Previously, people thought this area of the brain was only involved in motor function and learning, but we found it's involved in motivation and generating instant consumption," said lead researcher Alexandra DiFeliceantonio, a graduate student in biopsychology at the university.

This finding might have implications for people, she added, noting that it may be possible in the future to target the area with a drug that could block the impulse to overeat and thus may help people lose weight.

Experts note, however, that results in animal studies often don't translate to humans.

The new report was published Sept. 20 in the journal Current Biology.

For the study, DiFeliceantonio and her colleagues gave lab rats a drug to artificially boost the action of the neostriatum. The animals were then given M&Ms, and proceeded to eat twice as many as they normally would, she said.

"That's the same as a 150-pound human eating seven pounds of M&Ms in an hour," DiFeliceantonio said.

In addition, the researchers noted that the amount of a chemical called enkephalin, produced in the neostriatum, increased when the animals ate the chocolate treats.

It is the increased production of this chemical that increases the desire to overeat sweet and fatty foods, DiFeliceantonio said. When presented with a choice of usual food or M&Ms, the rats with high levels of the chemical consistently ignored their regular food and gorged on chocolates.

Preferring sweet and fatty foods is probably one of the things that helped humans to thrive, said Dr. David Katz, director of the Yale University Prevention Research Center in New Haven, Conn.

"We tend to like flavors, such as sweet, that in nature are associated with life-sustaining foods, and tend to dislike flavors, such as bitter, more often associated with toxins," he said.

The impulses that once helped keep our ancestors from starving, however, now may contribute to eating disorders and epidemic obesity, Katz added.

"But the fault here is not with the world within us, which is the same as it ever was," he said. It is with what and how much people eat, which has made the brain's natural functioning "backfire rather badly."

Another expert thinks the research could have implications for addiction and obesity.

Paul Sanberg, director of the Center of Excellence for Aging and Brain Repair at the University of South Florida College of Medicine in Tampa, said the findings "suggest areas of the human brain that might be looked at for eating disorders or addiction."

More information

For more on obesity, visit the U.S. National Library of Medicine.

TUESDAY, Sept. 18 (HealthDay News) -- If current trends continue, more than half the adults in 39 states could be obese by 2030, not just overweight, a new report says.

And 13 states could have adult obesity rates above 60 percent, while all 50 states would have rates above 44 percent, according to the report, released Tuesday by the Trust for America's Health (TFAH) and the Robert Wood Johnson Foundation (RWJF).

The toll on the United States in terms of both obesity-related diseases and health-care costs will be staggering, according to a new report.

"Twenty years ago, no state had an obesity rate above 15 percent," said TFAH executive director Jeff Levi at a Tuesday morning news conference. "Obesity is one of the most challenging health crises this country has ever faced."

Today, two-thirds of adults and nearly one-third of children and teens are overweight and obese, putting them at an increased risk for serious diseases, and 12 states have adult obesity rates above 30 percent.

In 20 years, as is the case today, Mississippi would have the highest obesity rate, although it would soar from nearly 35 percent now to 67 percent in 2030, according to the report, titled "F as in Fat: How Obesity Threatens America's Future 2012."

Colorado would remain the leanest state, but about 45 percent of its adults would be obese in 28 years, up from nearly 21 percent today.

Although states in the South and Midwest bear a disproportionate share of the burden, obesity "is truly a nationwide crisis," Levi said.

More obese adults means more people at high risk for serious health conditions.

The report projects another 6 million cases of type 2 diabetes by 2030, 5 million cases of coronary heart disease and stroke, and more than 400,000 cases of obesity-related cancer.

This is over and above an already sobering burden of 25 million Americans with type 2 diabetes, 27 million with chronic heart disease, 68 million with hypertension and 50 million with arthritis.

More sickness will translate into higher health care costs, the report said.

If obesity rates continue to climb, obesity-related health-care costs will jump by $48 billion to $66 billion annually. That doesn't include lost productivity, which could reach almost $600 billion per year, according to the report.

Obesity already costs the United States an estimated $147 billion to $210 billion annually.

But the report also offers a potentially rosier scenario: What would the future look like if states adopted approaches that could lower residents' body mass index (BMI, a measure of body fat) by just 5 percent?

Almost 800,000 people would be spared type 2 diabetes and 400,000 arthritis in California alone, the report said.

And health-care costs could decrease 6.5 percent to 7.9 percent.

According to Michelle Larkin, assistant vice president and deputy director of RWJF's Health Group, "pockets of progress" are already being seen. For instance, obesity rates in Philadelphia public school students have declined from 21.5 percent to 20.5 percent.

Larkin pointed to several policy initiatives that could help ease the obesity epidemic, including full implementation of the Healthy, Hunger-Free Kids Act, which has updated meal standards as well as investment in obesity-prevention programs.

TFAH's Levi said, "To realize this [healthier] future [we] need to invest in obesity prevention programs that match the severity of the problem. We can't afford not to."

More information

View the full report, F as in Fat: How Obesity Threatens America's Future 2012   at the Trust for America's Health.

SUNDAY, Sept. 16 (HealthDay News) -- People -- particularly women -- who read food labels while they grocery shop are thinner than people who don't, a new study finds. Women who checked nutritional labels weighed what amounted to nearly 9 pounds less than those who didn't.

The international team of scientists analyzed more than 25,000 observations on health, eating and shopping habits from the U.S. National Health Interview Survey. Among the data collected were responses about reading nutritional information in supermarkets -- if people did and how often.

"First we analyzed who read the nutritional label when purchasing foods, and then we moved on to the relationship with their weight," study lead author Maria Loureiro, of the University of Santiago de Compostela, in Spain, said in a university news release.

Nutrition labels tell consumers how many calories are contained in a food portion, as well as levels of sodium, fats, sugars, protein, dietary fiber and key vitamins and minerals.

The study found big differences between the people who read food labels and those who did not. Smokers, they noted, paid little attention to the nutritional information on foods.

"Their lifestyle involves less healthy habits and, as a consequence, it could be the case that they are not so worried about the nutritional content of the food they eat, according to our results," the researchers suggested.

People who live in cities were the most careful about reading food labels. People with high school and college educations also paid more attention to nutritional labels. Fifty-eight percent of men took the time to read labels, compared with 74 percent of women. White women who lived in cities read food labels most often, the study found.

"In general, the associated impact is higher among women than men. On average, women who read the nutritional information have a body-mass index [a measurement of body fat based on weight and height] of 1.48 points lower, whereas this difference is just 0.12 points in men," Loureiro said. "We know that this information can be used as a mechanism to prevent obesity.

"We have seen that those who read food labels are those who live in urban areas, those with ... high education," she added. "Therefore, campaigns and public policy can be designed to promote the use of nutritional labeling on menus at restaurants and other public establishments for the benefit of those who usually eat out."

The study was published in the journal Agricultural Economics.

More information

Visit the U.S. Food and Drug Administration to learn more about food labeling and nutrition.

(HealthDay News) -- Jumping rope is no longer just for 6-year-old girls. Experts say it's a great way to exercise your heart, and it can improve eye-hand-foot coordination.

The American Council on Exercise offers these suggestions for jump ropers who are just starting out:

• Keep a light grip on the handles.
• Hold your elbows close to your body and keep your shoulders relaxed.
• Keep your knees slightly bent.
• Use your wrist to turn the rope and create a smooth arc in the rope as it swings over your head.
• Maintain good posture with your head up and back straight.
• Don't jump too high. This will help reduce impact on knees and ankles.