Living with the guidelines
Let's hope we've convinced you that it ain't healthy to be fat. What can you do about it? Let us count the ways:

Visit Bally's gym. Avoid horizontal stripes. Sign up for Weight Watchers. Read The Why Files coverage of fast fixes for fatness (or, if it's too late, our minute-by-minute account of coronary bypass surgery).

As the fen-phen diet pill disaster illustrated, people are desperate to lose weight. But can it really be done? Don't people just regain lost weight on a roller-coaster that carries its own health risks?

Actually, the widespread pessimism about weight loss is unwarranted, says Michael Hamilton, director of the diet and fitness center at Duke University. "We used to say that everybody regained the weight, but part of our problem was the definition of successful treatment was unrealistic. We used to consider getting down to optimum body weight as the goal -- but now we know that moderate weight loss of 10 percent can lead to significant improvements in preventing heart disease."

Even liquid diets like Optifast are proving themselves in some studies, he adds. "A recent study showed that 30 percent of people kept at least 10 percent of their weight off for five years."

A review performed by the National Institutes of Health for its just-published guidelines on treating overweight and obesity found that low-calorie diets caused an average weight loss of 8 percent over a follow-up period of three to 12 months.

Since body fat accumulates when energy intake exceeds energy spent, scientists see sustained weight loss as a two-step process: Diets take the weight off, then exercise keeps it off.

One effective way to help patients lose weight and stay slim, Hamilton says, is using diaries and writing out meal plans. "People who plan what they are going to eat are more likely to follow it. Writing it down increases self-awareness."

Don't spare that spare tire
The new emphasis on obesity means doctors should start calculating the Body Mass Index (BMI) for patients, not just measure their blood cholesterol or blood pressure, says Karen Donato, who coordinates the obesity education initiative at the National Heart, Lung and Blood Institute.

The BMI, an accepted measure of fatness, is not perfect, since it does not reflect other conditions that affect overall health. For those who are overweight (BMI between 25 and 29.9), she adds, "it's important to have other risk factors assessed and the waist circumference measured." That's because belly fat, which men tend to have, is worse for the heart than the thigh-and-buns fat that plague women (see "Not All Fat Is Alike" and "Do 'Apples' Fare Worse than 'Pears'?" in the bibliography).

For people who are simply overweight, Donato says, "If you have other risk factors, you'd probably benefit from losing weight." Those who are not motivated to slim down will still be helped to avoid gaining weight, she adds.

For those with a BMI above 30, the benefits of weight loss are much clearer, Donato says.

Lo-fat but hi-cal
In an era when practically everything from potato chips to wallpaper paste is labeled "low fat," losing weight should be as easy as slathering a low-fat chocolate cake with low-fat ice cream, and spritzing on some low-fat whipped cream. So why is the American population getting fatter even as it eats less fat? Because (and here's the bad news), experts say calories still matter -- since the body can convert carbohydrate calories into fat quite nicely, thank you.

"There's a lot of emphasis on the need to reduce fat, we have healthy this and healthy that," says Donato. "People sometimes take that as a signal to eat in the quantity they would not otherwise. Perhaps we have lost sight of the fact that calories still count in foods."

And when dinner's done and the remains of the heavily marbled steak are in the trash, it's best to go for a brisk walk. The flip side of eating, after all, is burning off those new calories before they can inflate your spare tire. Experts say moderate to vigorous exercise, 30 minutes a day, on most days of the week, is essential to any weight-control program. Not to be outdone, The Why Files has advice for keeping those old bones moving.

Then we'll have enough energy to order some delicious fried cheese curds...

We've found some reading and surfing on obesity.