Diet

For a country in which roughly 200 million people are overweight or obese, scientists today have discouraging news: Even those who maintain a healthy weight probably should be eating less. Evidence has been mounting for years that the practice of caloric restriction -- essentially, going on a permanent diet -- greatly reduces the risk of age-related diseases and even postpones death. It has been shown to significantly extend the lives of yeast, worms, flies, spiders, fish, mice and rats.

Eating red meat increases the chances of dying prematurely, according to a large federal study offering powerful new evidence that a diet that regularly includes steaks, burgers and pork chops is hazardous to your health. The study of more than 500,000 middle-age and elderly Americans found that those who consumed the equivalent of about a small hamburger every day were more than 30% more likely to die during the 10 years they were followed, mostly from heart disease and cancer.

What's new: The risk of breast cancer is apparently higher in populations living far from the equator than it is for those in the sunny tropics. The finding: Researchers at UC San Diego reported in the recent issue of the Breast Journal that in countries where people are exposed to high levels of ultraviolet B (UVB) radiation from the sun, breast cancer rates are lower than in countries where UVB levels are low.

Heidi BARAJAS was active as a child, despite weighing more than her peers. She loved sports in high school, but her fitness regimen got derailed in college, a combination of working and a knee injury. Her weight crept up, leading her to try "every diet in the world," which usually worked to take the pounds off but not to maintain the weight loss.

Bonnie SHERIFF, 26, left Kansas for California to attend Caltech in 2003. In the process, she chucked her typical Midwestern meat-and-potatoes diet and decided to slim down, going from about 180 pounds in high school to 127 now. The doctoral candidate, who lives in Pasadena, exercises about three to four times a week and sticks to a diet heavy on whole grains, fruits and vegetables. Once an asthma sufferer, she says she now has "virtually no symptoms" and has increased energy and stamina.

Susan Phillips' 4-year-old son Alex eats vegetables every day -- he just doesn't know it. Phillips purees his servings of green beans, spinach, sweet potatoes and squash and hides them in a peanut butter and brown sugar-sweetened porridge that she makes for him each morning. Without the deception, she says, Alex would eat no vegetables and very little fruit. His resistance is so strong that she has pretty much stopped putting them on his plate and requiring him to take a taste.

Anyone who ate gluten-free food five or 10 years ago might understandably opt to avoid such food forever after. In the old days, "we used to joke that when you got the food, you didn't know if you were supposed to eat the box or the contents," says Dr. Alessio Fasano, medical director of the Center for Celiac Research at the University of Maryland.

A long-running comparison of three diet plans found that the low-carbohydrate Atkins regimen and a Mediterranean diet rich in fish and nuts produced slightly greater weight loss than a low-fat program modeled on American Heart Assn. dietary guidelines.

The equivalent of nine glasses of wine a night is just dinner to the pen-tailed tree shrew, a small Malaysian mammal resistant to the effects of chronic drinking, researchers reported Tuesday in the Proceedings of the National Academy of Sciences. The shrew's drink of choice is bertam palm nectar, naturally fermented to have an alcohol content up to 3.8% -- just a few tenths of a percent shy of Guinness Draught beer.

After his new movie "Zack and Miri Make a Porno" reaches theaters Friday, Kevin Smith plans to start counting his calories. Since his doctor called him morbidly obese, he's giving up the all-you-can-eat lifestyle and taking a "health sabbatical" intended to shed extra pounds he packed on while filming the raunchy, Seth Rogen-starring romantic comedy in Pittsburgh last year.