Cornell University scientist Brian Wansink is the king of mindless eating. Not because he permanently has his hand in a box of Junior Mints, but because he has studied, psychoanalyzed, and otherwise tried to crack the code of why we eat so much. As I've written before, he focuses on all the cues in our environment that cause us to overeat without realizing it and gives advice on how to re-engineer our surroundings to encourage better habits.

During a conference call today sponsored by the International Food Information Council, Wansink explained why the holiday period is chock full of unhelpful eating cues. First, no matter the time of year, we are pretty useless at realizing how much the plates and other dishes from which we serve and eat influence how much we eat. Even after being warned that bigger bowls lead to overeating, we will still go ahead and pig out when we're given a big bowl. Moreover, letting our own appetites—the inner voice that says, "I'm not hungry anymore"—govern how much we eat is a losing battle. Most Americans simply don't think in those terms, he says. His research has shown that Parisians say they'll stop eating when they're no longer hungry or the food no longer tastes good; Chicagoans typically say they stop when the plate is empty, when everyone else is finished, or when the TV show is over(!). Finally, the calories in family recipes have been rising over the years, either because of more calorie-dense ingredients or because a casserole that was once intended to feed six or eight people is now consumed by a smaller family of three or four.

Everyone knows that kids are in the midst of, as pediatric exercise scientist Avery Faigenbaum calls it, an "unfitness epidemic." According to a July report on the nation's obesity problem, fewer than a third of kids between the ages of 6 and 17 take part in regular vigorous activity, defined as 20 minutes at a stretch of exercise intense enough to break a sweat and prompt heavy breathing. But on the other, smaller end of the spectrum, never have youth sports been taken so seriously by those who participate (and their parents): In addition to high school teams, private club teams, all-star traveling teams, sports camps, and the like are de rigueur for many teen and kid athletes.

So how to get from point A (the sofa) to point B (the school soccer team), or at least to somewhere in between? Enter youth fitness and training programs, which run the gamut from inexpensive programs at the YMCA or local Boys and Girls Club to sessions with private instructors (often as an offshoot of a general training business)that cost as much as—or more than—a personal trainer at the gym. Here are six tips to keep in mind when you're considering a program:

Wasn't the coming generation of senior citizens supposed to be the most active of all? The baby boomers may not be power-walking happily into their later years after all, if the trend captured by a new study continues. Researchers from the David Geffen School of Medicine at the University of California–Los Angeles found that people ages 60 to 69 report more disabilities (things like being unable to walk up 10 steps without rest and having difficulty doing chores and getting dressed) than in years past. While those are not the boomers—the people studied were born before the end of World War II—the researchers pointed out that there are large and none-too-pretty implications if members of that huge demographic group end up becoming similarly burdened by disability. (Who will take care of them all?)

The study, published online in the American Journal of Public Health, wasn't designed to pinpoint the cause of the changes. It simply looked at government survey data from 1988–1994 and 1999–2004 to track changes in disabilities over time. But one possible explanation, the authors wrote, is that while obesity is a problem across the board, African-Americans and Hispanics tend to have higher rates of obesity and lower socioeconomic status, both of which are tied to disability, and a growing proportion of 60-to-69-year-olds are from those ethnic groups. But even controlling for things like weight, health, and demographics, there was still an effect that couldn't be accounted for. Complicating things further is that people over age 70 either showed no change or an improvement in disability rates.

If, like me, you've ever taken yoga classes and waited fruitlessly to be infused with ancient wisdom, you'll love a documentary out on DVD today. "Enlighten Up!" traces the journey of Nick Rosen, a guinea pig handpicked by the documentary's maker, Kate Churchill, as he tries various styles of yoga and travels in the United States and India to explore its roots. The pair scores interviews with figures ranging from B. K. S. Iyengar, who created the popular eponymous style of yoga, to "Diamond" Dallas Page, a former pro wrestler who now teaches yoga to "regular guys."

The tension in the film comes from Churchill's Tracy Flick-esque determination (via her questioning of Rosen) to make him see the light when it comes to yoga's spiritual, transformative side, even as he remains skeptical. Rosen is a journalist with a pitch-perfect pedigree for this project: His father is a lawyer and his mother a shamanistic healer. While he appreciates yoga for what it contributes to his physical fitness, its deeper meaning is elusive. I won't ruin the end, but suffice it to say that while he isn't untouched by the experience, he doesn't achieve the result that Churchill probably wished for him at the outset of filming.

Alzheimer's disease is known for the knockout blow it delivers to memory and other cognitive functions. But this disease of the brain may also be linked to muscle weakness, according to a study published today in the Archives of Neurology. Among the 900 older adults in the study, those who were initially stronger had a smaller chance of getting Alzheimer's in the future. (The average follow-up time was 3.6 years.) Muscle strength was also tied to a lower risk of developing mild cognitive impairment, the precursor to Alzheimer's disease, the study found.

As tempting as it is to yell from the hilltops that hitting the gym prevents Alzheimer's, this study wasn't designed to tell if there's a causative effect, says Patricia Boyle, a neuropsychologist with the Rush Alzheimer's Disease Center in Chicago and an author of the study. It's looking like one degenerative process drives both conditions, and it shows up first as muscle weakness before manifesting itself as cognitive problems. That common danger may be damage to the mitochondria—the cells' energy factories—or central nervous system disorders like stroke, the study authors say. Or, the same accumulations of plaques and tangles in the brain that are characteristic of Alzheimer's disease may be responsible. "We know they cause cognitive problems, but there's increasing evidence that they cause motor dysfunction," says Boyle. That suggests that screening older folks for muscle strength may offer a way to identify who is most at risk of the disease, she says.

It's been a bad autumn for deaths during U.S. running races—at least six during half marathons and one during a marathon. Although the specific causes of death aren't known in all cases, heart ailments are at the top of the list of possible explanations whenever someone dies suddenly during an athletic event, be it a road race, triathlon, or a football or basketball game. As rare as these events are when compared with deaths from car accidents, homicide, or even the flu, doctors are debating whether lives could be saved by more carefully scrutinizing athletes before they compete. Sounds good, but is it possible?

First, let's understand what problems doctors are trying to ferret out, and in whom. When a middle-aged person experiences sudden cardiac death or a fatal heart attack during athletic exertion, he is more likely to have plain old heart disease (also called coronary artery disease) caused by a buildup of plaque inside the blood vessels leading to the heart, says Euan Ashley, an assistant professor of cardiology at the Stanford School of Medicine and director of the Stanford Hypertrophic Cardiomyopathy Center. But when a high school, college or younger elite athlete collapses and dies, he or she most likely had an undiagnosed inherited cardiovascular disease, most commonly hypertrophic cardiomyopathy, in which the heart muscle thickens and can throw off the rhythm of the heart. (Other electrical malfunctions in the heart are also a possibility.)

Why are these problems an issue during sporting events or strenuous exertion? While exercise can dramatically cut the chance of heart disease, during the minutes you actually are exercising, your risk of a heart attack or sudden death actually temporarily rises, says Ashley. The long-term benefits of exercise vastly outweigh any short-term risk, so there's no excuse for not exercising unless your doctor specifically orders it. (Even 2007 research on the body-stressing marathon suggests that it's riskier to drive the course than to run it.)

On Sunday, November 1, some 42,000 runners will share the experience of running the ING New York City Marathon. But marathon organizers are taking special measures to make sure they won’t also be sharing the flu—specifically, the H1N1 virus, aka swine flu.

For the first time, marathoners’ goody bags—customarily filled with things like minipacks of pain relievers and samples of energy bars—will include small hand sanitizer sprays printed with the logo of the New York Road Runners, the organization that puts on the race. The official marathon program also says hand sanitizer will be available at the prerace expo and the race's start.

Is a traffic light coming to U.S. food labels? It certainly sounds like a possibility. The Food and Drug Administration said today that it's concerned about the proliferation of front-of-package nutrition labeling programs like Smart Choices, which are supposed to offer quick and easy guidance to consumers on purchasing more healthful foods. Trouble is, as the FDA said in a letter to the food industry, the different programs have different criteria, which can be confusing for consumers. They may also be violating the law if they give false or misleading information or convey an overall impression of healthfulness even if the nutritional content shows otherwise. (Hello, Froot Loops, which FDA Commissioner Margaret Hamburg described but did not specifically name as a Smart Choices-approved cereal, even though it has more than 40 percent sugar. Smart Choices, meantime, said in a statement that it complies with all laws and regulations and looks forward to working with the FDA.)

The Institute of Medicine has new recommendations for the federal programs that provide breakfast and lunch in primary and secondary schools, and for the first time, it endorses calorie limits. The IOM report says lunches shouldn't be more than 650 calories in grades K through five, 700 for middle schoolers, and 850 for grades 9 through 12. Breakfasts, meantime, should range from 500 to 600 calories depending on the grade.

The report also advises that schools offer more—and more varied—fruits and vegetables, including one cup per day of fruit at breakfast and an additional cup for high schoolers at lunch. Juice should make up no more than half of the fruit provided. More veggies should also be offered, and at least a half cup should be from the "rainbow," meaning leafy greens or orange vegetables rather than starches, such as potatoes. If kids are buying food a la carte, they should be required to take at least one serving of fruits or veggies per meal. The IOM also said schools should move toward whole-grain products rather than the refined variety, and 1 percent or nonfat milk rather than whole or 2 percent.

How well do you move? It sounds like an easy question—or one that might be answered by your performance on the dance floor. But it's neither. Whether you can perform a deep squat or leg lift, for example, can indicate areas of the body that are tight or weak and show if you're compensating in a way that might be harmful even if you aren't consciously aware of it. That's the philosophy behind the Functional Movement Screen, a tool used to root out those weaknesses before they hamper your sports performance or become full-fledged injuries.

Gene Schafer, an athletic trainer, challenged—er, invited—me to take the screening test at the rehab and training facility he owns, ARC Athletics in New York. I was fairly confident I'd ace it. After all, this test doesn't aim to evaluate your athletic performance but "movement patterns that are key to normal function," according to the FMS website. If I run, swim, and strength-train several times a week, surely I've got those basic movement patterns down pat, I thought.