It seems there's nothing like dropping a few pounds to turn somebody into an instant dieting expert.

It seems there's nothing like dropping a few pounds to turn somebody into an instant dieting expert.

Everywhere you go, you can hear people talking about their latest dieting exploits and advising others on what they should do to lose weight.

"You should try the X Diet. My sister went on it and lost a ton of weight!"

"The New Y Diet is the way to go. I hear you can lose 10 pounds in a week!"

"I'm on the Ultra Z Diet. Just eat meat and the pounds melt off."

Sound familiar?

Yet the people who talk the most about dieting are often the ones who know the least about effective weight control. The talkers are usually chronic dieters, continually starting yet another diet, only to drop it, regain their weight and get back on the next fad diet that comes along.

It's great for the dieting industry to have these folks as their spokespeople, but is it good for you?

Effective weight loss lasts a lifetime. Good weight-loss methods teach behaviors that can be followed easily for the rest of our lives so we aren't starting over again and again.

By that measure, yo-yo dieters, however well-intended, are the worst people to be handing out advice.

Despite the obesity epidemic, there are plenty of people who have always been thin and have never dieted, or who once had a weight problem that they've effectively managed for years.

They're the experts on how to be thin. But they don't get much attention except when their chubby friends joke that they hate them for their seeming ability to eat all they want without getting fat.

Still, whatever the thin person is doing is keeping them thin. So instead of talking to the constant dieter, we should be talking to long-term thin people and picking their brains about what they do to be lean.

Actually, you'll probably have to observe rather than talk to the thin person because they might not be able to tell you what keeps them thin.

Unlike chronic dieters, naturally thin people often don't pay a lot of conscious attention to their weight and what they eat. Some may have a casual focus on their health and weight, engaging in good eating and exercise habits with no more thought than you put into brushing your teeth every morning — they just do it.

If we look at what good science has discovered about how the body gains and loses fat, it all becomes clear. Thin people tend to do the things that burn fat and avoid fat gain. And, they do it as a lifestyle.

Overweight people, in general, move less than thin people, and nothing burns fat more than moving. Scheduled activities such as working out at a gym, jogging or taking aerobics classes are important for fat-burning because our modern lifestyles do not provide enough activity on their own. However, just moving more in general, such as being more active around the house, watching less television, standing instead of sitting or even just fidgeting, all burn a lot of calories without much notice.

Don't believe it? Watch your thin friends. Better yet, start moving more and see what it does for you.

If we really want to know how to be thin, it's time we started studying thin people instead of envying them. They're the real experts on staying thin for a lifetime.

Lavinia Rodriguez, a clinical psychologist who specializes in weight management, is author of the book, "Mind Over Fat Matters: Conquering Psychological Barriers to Weight Management."