Today, my brother weighs 165 pounds—what he weighed at age 23—and his doctor has taken him off all his medications. He has his vigor back, and a brisk three-mile walk is a breeze for him.

Sorry if this sounds like a commercial for a miracle weight-loss program. But in fact my brother did it with plain old diet and exercise, by counting calories and walking. He had no surgery, took no supplements or pills, ate no unusual foods, had no dietary restrictions, embarked on no extreme exercise regimen. He will need to work his whole life to keep the weight off, but he shows every sign of being on the right track. He has changed his eating and exercise habits, and insists he enjoys the new ones more than the old.

In short, Dan seems a lot like many of the people in the National Weight-Control Registry, the research database of those who, despite the popular wisdom that avoiding weight regain is a Herculean task, have kept off a minimum of 30 pounds for at least a year. Most of us know someone who lost weight years ago and has kept it off, and we all see celebrities who claim to have slimmed down for good using plain old diet and exercise, from Bill Clinton to Drew Carey to Jennifer Hudson. But we keep hearing that the vast majority of us—98 percent is a figure that gets thrown about—can’t expect to do the same.

Alcoholics don’t seem to face such dismal prospects, thanks to Alcoholics Anonymous and similar multistep programs, which are widely regarded as effective treatments. With obesity, we’re apparently at a loss for a clear answer. Fads like the Atkins diet slowly fade in popularity after dieters watch the weight return. We’re left with the impression that the techniques needed to permanently lose weight don’t exist, or apply to only a tiny percentage of the population, who must be freaks of willpower or the beneficiaries of exotic genes. Scientists and journalists have lined up in recent years to pronounce the diet-and-exercise regimen a nearly lost cause—a view argued in no fewer than three cover stories and another major article in The New York Times Magazine over the past 10 years, and in a cover story in this magazine two years ago.

All of which is odd, because weight-loss experts have been in fairly strong agreement for some time that a particular type of diet-and-exercise program can produce modest, long-term weight loss for most people. But this program tends to be based in clinics operated by relatively high-priced professionals, and requires a significant time commitment from participants—it would be as if the only way to get treated for alcoholism were to check into the Betty Ford Center. The problem is not that we don’t know of a weight-control approach that works; it’s that what works has historically been expensive and inconvenient.

But now that’s changing. Consider my brother, who has never been to a weight-loss clinic. His program has taken place entirely in his home, at his office, and when he’s out at restaurants or visiting friends and family—and it happens at his convenience, or even automatically, literally without his doing more than lifting a finger.