Smoke and mirrors have a lethal chemistry. The link between tobacco use and our obsession with thinness is one reason medicine is losing the war on smoking.

Although 32 million of the estimated 46 million American smokers reportedly want to quit, only 2% to 3% successfully kick the habit each year. At the same time, more females are taking up smoking, and are projected to outnumber male smokers by the year 2000. Why this backslide, even after lung cancer has topped breast cancer as a killer of women?

The answer in part is that women are dying for a smaller dress size. The 5 pound to 10 pound weight gain that accompanies quitting is seen by some as too high a price to pay in our fat-phobic culture.

From earliest cigarette advertisements ("Reach for a Lucky instead of a sweet") to today's slinky magazine ads for Virginia Slims and Capri Superslims, tobacco companies seem to have long exploited the link with thinness. While the appeal is targeted primarily to women, men also fear softening their hard bodies.

"Using cigarettes is like using an anorectic [appetite supressing] drug," says Janet Gross, a psychologist at Johns Hopkins School of Medicine.

But psychologist Bob Klesges of the University of Memphis argues cigarettes are a "crummy weight-control strategy," offering an average eight-pound weight difference, at a high cost of heart, lung, cancer and reproductive risk.

Joseph Califano, former secretary of Health, Education and Welfare in the Carter administration, was a four-pack-a-day smoker who gained 30 pounds when he quit. Now president of Columbia's Center on Addiction and Substance Abuse, he wishes he had focused more while in Washington on the deadly synergy between smoking and weight control. "If you look at pictures of me after I quit, I was jowly," says Mr. Califano. "I took of 15 pounds by eating less cheese and dessert, and by jogging."

Stop-smoking campaigns will fail, he believes, unless they tackle the weight issue head-on. "We have to make it chic to be a non-smoker," he says. "And we have to accept the fact that not everybody has to look like a social X-ray, to borrow a phrase from Tom Wolfe."

To a smoker, current health messages cancel each other out. Smoking and obesity are denounced as the No. 1 and No. 2 causes of preventable disease and death. But the American Lung Association is trying to clear the air by restoring smoking cessation as priority one.

Edwin Fisher, a psychologist at Washington University in St. Louis says people quitting cigarettes should be reassured that a modest weight gain not only isn't their fault, but also is biologically programmed.

"Smoking tends to damage metabolism," he says, by reducing the body's tendency to store energy as fat. "So when people quit smoking, their body is normalizing, not blimping. They're just responding to a sudden change in chemical intake."

Nicotine touches off complex biochemical reactions in the body, including stimulation of the central nervous system and acceleration of the body's basal metabolism, causing smokers to burn more calories at rest than non-smokers. Further, nicotine supresses the appetite, and studies suggest its withdrawal may spark a specific craving for carbohydrates, says Phyllis Pirie of the University of Minnesota.

When a former is ready for weight control, here's what Dr. Fisher and the Lung Association recommend:

1. Don't blame yourself for gaining weight. It's partly biological and partly behavioral.

2. Recognize that quitting smoking is far more important to your health than a 10 pound weight gain.

3. Get off the merry-go-round of quitting smoking, gaining weight and resuming smoking to lose weight. Don't put out much effort to lose weight until you can restrict food intake without experiencing the urge to smoke. For most people this will take six months.

4. Exercise. It's a good solution for both quitting smoking and for weight management. It reduces tension formerly soothed by lighting up, and helps to manage weight without restricting food.

5. After you feel secure as a non-smoker, you might begin trying to lose weight gained in quitting.

6. If dieting triggers cigarette cravings, go back to No. 2. Recognize that it's more important to quit than to lose weight.

Studies suggest that products offering nicotine replacement help smokers quit while forestalling some weight gain. Janet Gross, a professor of behavioral biology at Johns Hopkins School of Medicine, believs that while either gum or a patch will help you quit, it's the gum that helps fend off weight gain - at least temporarily. She speculates it's because gum offers oral gratification and delivers nicotine through the lining of the mouth.

Also, eating better and exercising before the quit-date make sense. "Get good habits in place before you break bad ones," Dr. Fisher says.

Take your time, adds Dr. Gross. "We don't advise smokers to change too many things at once - especially if it involves deprivation."

Phyllis Pirie, professor of epidemiology at the University of Minnesota, agrees. In her study of 416 smokers, people who undertook simultaneous programs for quitting smoking and losing weight did the worst at quitting smoking. "We think we may have overloaded them," she says. "They just gave up."