Welcome to Fantasy Diet!

David L. Katz

If, like me, you are of a certain age, I trust you remember the show Fantasy Island. Mr. Roarke, deftly rendered by Ricardo Montalban, was ever impeccable in spotless white and seemingly unflappable. He was, presumably, representing God--or God's understudy.

Mr. Roarke would greet all guests with a hearty "welcome to Fantasy Island!" He would then proceed to divert their fantasies. On a weekly basis, guests discovered that what they thought they wanted was a distraction from what truly mattered. A bracing dose of constructive reality won out over fantasy every time.

Do you think, maybe, there's a message there for the rest of us?

This time of year, fantasies turn preferentially to weight loss. We have heard that for 2013, weight loss yet again tops the list of popular resolutions. And if we managed to miss that memo, we would get much the same impression from the sudden deluge of ads for weight-loss programs, lotions, and potions in print, online, and on air.

Some of these, of course, are legitimate, the best of which are highlighted right here at U.S. News & World Report. But this is also a topic awash in hucksterism--so, overwhelmingly, it's a great big load of hooey and caveat emptor.

[See Diets That Don't Work--And A Look At What Does]

This annual accentuation of our preoccupation with weight loss, and the fanciful promises devised to exploit it, are really just seasonal icing on a more constant cake. Many of us are tempted to visit weight-loss fantasyland throughout the year.

If we weren't inclined to believe virtually any claim about quick-fix weight loss and effortless health promotion, quite a few food companies and their partners on Madison Avenue would need a serious redirect.

What, for instance, would there be to say about energy drinks if we all recognized that they are not a meaningful or lasting source of energy? Sports drinks, of course, do not confer athletic prowess, despite compelling advertisements suggesting they do. Plain water has been the go-to rehydration beverage of hard-working Homo sapiens since--well, since before we were Homo sapiens!

[See The Energy Drink, Deconstructed]

Sugar substitutes may or may not lead to a reduced intake of sugar and calories overall. Diet sodas do not discernibly help people "diet." And for that matter, dieting does not discernibly help people with lasting weight control. Diets we go on and off give us weight that comes off and back on, generally with interest. Tell us what we've won, Johnny!

If it sounds too good to be true, it almost certainly is. Welcome to Fantasy Diet! Again.

As a doctor for over 20 years, I've been privileged to have very intimate conversations with many and diverse people--my patients. They, and the other people in my life, have given me abundant cause to believe in the value and prevalence of good sense. I think most of us have it.

But for whatever reason, we seem to turn it off when the topic turns to weight loss. I've lamented the divide between common sense and weight control before, and see no signs yet of the situation improving. When it comes to weight loss, the application of common sense is almost shockingly uncommon.

[See Recipe for Health]

But we in fact do have evidence of what needs to be done to lose weight, find health, and make it all stick. It's not a lotion or a potion, and it's not a diet that helps you lose weight as fast as possible. It's a commitment to healthy living. It's the application of willpower to acquiring the necessary skill power. It's about eating well and being active, and adjusting your daily routine as required so you can do these things forever--preferably, together with the people who matter most in your life.

The evidence this works is found in many places, but perhaps most visibly and best organized in the database of the National Weight Control Registry. The thousands in the registry who have lost a lot of weight and kept it off for years eat sensible diets and get moderate exercise. That same formula is what prevented diabetes in almost two-thirds of high-risk adults in the Diabetes Prevention Program. And that same formula is what keeps some of us from ever needing to lose a lot of weight in the first place.

[See Diet, Diabetes, and Doubt: Is Preventive Medicine Lost in Space?]

If I may paraphrase Tattoo of Fantasy Island: It's plain! It's plain! We are not clueless about the basic care and feeding of Homo sapiens. We know what healthy living looks like. We even know how to lose weight and keep it off.

Every fantasy about what diet can do is true. In fact, given that eating well in combination with routine physical activity and not smoking could help eliminate up to 80 percent of all chronic disease and alter the behavior of our very genes, there's a good chance your fantasies about what diet could do for years in your life and life in your years may not go far enough!

[See In Pictures: 11 Health Habits That Will Help You Live to 100]

But fantasies about alternatives to eating well and being active are another story altogether. Fantasies about what diet can do are only realized if you can handle the truth--and stop subsisting on a diet of quick-fix fantasies.

Of course, Mr. Roarke was never the only source of wisdom in the world. There's also the Rolling Stones. In the immortal words of Mick Jagger: You can't always get what you want.

If you want magical, effortless, overnight weight-loss success: fuggedaboudit! But someone will be happy to take your money.

You can't always get what you want. It may well be that the only hope of getting what you actually need to achieve lasting weight control and vitality begins by admitting that, and letting go of all the fantasies.

Hungry for more? Write to eatandrun@usnews.com with your questions, concerns, and feedback.

David L. Katz, MD, MPH, FACPM, FACP, is a specialist in internal medicine and preventive medicine, with particular expertise in nutrition, weight management, and chronic-disease prevention. He is the founding director of Yale University's Prevention Research Center, and principal inventor of the NuVal nutrition guidance system. Katz was named editor-in-chief of Childhood Obesity in 2011, and is president-elect of the American College of Lifestyle Medicine.