Finally I don't have to feel guilty anymore. Swedish researchers have come to my rescue. Their findings are based on good science, my doctor assures me. My behavior is not considered medically incorrect. I don't have to keep this a secret anymore.

I'm a yo-yo dieter.

It's not that I yo-yo up and down the scales. But I yo-yo on and off food. To maintain my weight within acceptable bounds, I fast at least one day a week. I put myself on what the doctors call a VLCD--a "very low calorie diet." I resist temptation by cutting out all meals. Instead I take vitamins, drink fluids and three times a day I eat a packet of protein powder prescribed by my doctor mixed into a bowl of yogurt. That's my VLCD, less than 600 calories a day. I get all the nutrients I need, but no real food.

About five years ago, I wrestled with flesh creep and took off 20 pounds under a doctor's supervision. Like most people, I had a pretty easy time losing the weight. Keeping it off was the bear. So I turned to fasting. I'm healthy with no underlying diseases that might raise concern with this approach, so my doctor gave me the green light.

I'm like a monk who looks forward to that day of deprivation. Sometimes, I do two half-days. After a vacation of gourmet dinners, or a pig-out party weekend, I'll go on my special diet for a day. Or two. Or even three, max.

The VLCD is my safety valve. I know I can always keep those few pounds off with my packets and yogurt. The rest of the time, I don't worry. I have a life.

This conflicts with the Cotton Mather rules of dieting, which condemn you to an eternity of suffering and salivation to improve character and slim thighs through self-denial.

It flies in the face of all the diet books, each one promoting the one true path. Cut out fats? Cut out carbohydrates? It's a cold war out there among the experts.

Fasting also ignores the very sensible advice from federal health officials that you should have a balanced diet and live quietly under the tyranny of moderation. Just a sliver of pecan pie; better still, choose a peach for dessert. Stick with a fistful of lettuce. Show restraint day in, day out. Serving portions no larger than a pack of cards. Have you ever seen a prime rib the size of a pack of cards?

I needed to find a way to keep my sense of exuberance in life without succumbing to the sins of excess.

VLCD was the answer for me. But I always felt that I was cheating.

Now an article in the International Journal of Obesity suggests I'm not a medical malefactor. Indeed, intermittent dieting may work as well as being on a diet all the time.

The study of more than 100 obese patients concludes that those who took the yo-yo approach to weight loss--two weeks on the VLCD, two weeks off, two weeks on, two weeks off--were just as successful as those who stayed on the very low calorie diet continuously for a six-week period. What's more, it was safe to follow a low calorie diet for as long as two weeks without physician supervision.

"Intermittent VLCD treatment seems to result in long-term weight losses and compliance similar to those obtained by more continuous VLCD therapy," concludes the author, Stephan Rossner, of the obesity unit at the Huddinge Hospital in Sweden.

Of course, this experiment took place in a hospital setting where the goal was significant weight loss. And even those who went off the VLCD stuck to a restricted low-fat diet. But the results are reassuring.

According to the study, it's medically acceptable to fast on again, off again. Whatever works for you to control your weight. My doctor says a number of his patients have chosen the fasting route to keep the poundage off. "It's a way," he says. Not the way, but a way.

The truth about maintenance is that it involves more than following a diet. It's about making a permanent change in behavior. As my doctor says, "People are usually successful at losing weight. But how well you maintain your weight seems unrelated to how you lost the weight. You can lose it rapidly, slow. Smart or stupid. Aggressively or conservatively. How well you maintain it is an independent issue."

Everybody has to make a choice--how to manage a lifetime of good nutrition and good cheer without flesh creep. "It's all calories in and calories out," says my doctor. Exercise can take the calories out. My weekly fast lowers the calorie count going in. "It's a simple and convenient way of eating less," he says.

But it's not for everybody. And like all diets, it is filled with delusion. Fasting one day doesn't give you license to gorge the next. Fasting through half a day and then sitting down to a dinner of lamb chops and a chocolate torte is self-sabotage. That's the trouble with any diet: You can always sabotage it.

The main thing is to find the way that works best for you. The proof, as it were, is in the pudding.