LOSE THE FAT, KEEP THE muscle."

For many months these full-page ads have been appearing in fitness magazines. Besides having the perfect slogan to match conventional health wisdom, they promote chromium picolinate as a dietary supplement. It's a mineral you can purchase at many drug and health-food stores, by itself or combined with other minerals and herbs.

The ads claim that chromium is an essential mineral in human nutrition. Which is true enough. They say that most of us get less than 50 micrograms a day, when usual recommendations fall between 50 and 200. Also true.

Then they go on to advocate chromium picolinate, a synthetic form of chromium better utilized by the body than plain chromium or even chromium found in foods such as brewer's yeast. It can benefit our health and fitness by helping to reduce body fat and increase lean muscle, they say, citing scientific studies that back up those conclusions.

That's where the debate begins. Other researchers and doctors say the results aren't nearly conclusive enough.

"I guess I kind of started it," admits Gary Evans, a professor of chemistry at Bemidji State University in Minnesota. While working for the federal Department of Agriculture in the mid-1970s, Evans discovered that we absorb chromium more effectively when it's combined with picolinic acid (a substance the body makes from the amino acid tryptophane).

When chromium is better assimilated, Evans says, it helps the body's natural insulin do its job better. "And insulin doesn't just control blood sugar; it controls everything we eat, where it goes and what happens to it," Evans says. When insulin is working well, it helps fat move efficiently from fat cells to muscles. So we get energy from stored fat, instead of depleting our muscles.

Evans believes that some of the 50-plus studies done on chromium picolinate also suggest other possible benefits: helping diabetics, cutting cravings for sweets, raising energy and metabolic rate, lowering blood pressure, retaining calcium for post-menopausal women, and even increasing DHEA, a so-called anti-aging hormone.

There's a book, of course ("The Chromium Program," by Jeffrey Fisher, M.D., forward by Evans), and a Chromium Education Bureau (1-619-688-5207) and abundant information from Nutrition 21 (1-619-488-7423), a San Diego supplier of nutritional trace elements that has the exclusive lease of the chromium picolinate patent from the USDA.

Whew. Evans and his wife feel confident enough in the benefits of chromium picolinate to take 400 mcg. each day.

Dr. Stuart Willick, however, is not so convinced. A medical resident in rehabilitation medicine at Harborview Medical Center, he's planning a study (under attending physicians Robert Schoene and Anthony Margherita) to test the effect of 400 mcg. of chromium picolinate on muscle strength, body fat, aerobic and anaerobic levels. Willick, who agrees with Evans that there's no known toxic level of chromium in the picolinate form, hopes to have results by this time next year.

Willick agrees that, in theory, chromium might help. But he thinks there's not enough evidence yet to warrant the "Lose the fat, keep the muscle" conclusion. (Chromium picolinate supposedly works best when we also exercise and eat a low-fat diet - but what doesn't?)

"For every study that has shown a change in body composition," Willick says, "there are studies that do not show a change in body composition." He questions some of the pro-chromium-picolinate research, citing technical issues such as design, controls, double-blinds and human vs. animal subjects. But Willick also wonders why chromium, which is well known in micronutritionists' literature, hasn't been studied more by endocrinologists for its possible relevance for diabetics.

Even if the Harborview/UW study shows some fitness benefits, more questions arise, Willick says. Which aspects did it help? What's the optimal dose? Does it work for some people and not others? For weight lifters and not runners? Men or women? Older folks vs. younger?

"I don't have a vested interest in the results, one way or the other," Willick says. "I just want to see what the truth is . . ." Then he let loose a little smile.

"And whether I should start taking it."

Molly Martin is assistant editor of Pacific. ----------------------------------------------------------------- NOTEBOOK

Profile Yourself

NordicTrack is offering free health-related assessments throughout 1995. Answer 30 to 40 questions by filling in circles on a computer form, feed the paper into a machine, and come away with ratings from "Tops" to "Help!" in several categories.Profiles on nutrition and stress are available through mid-March, followed by one on walking. Local NordicTrack stores are at Bellevue Square, Alderwood Mall and Northgate.

H2O Lite

Light coconut milk sounded like a dream come true for fat-conscious coconut-milk lovers like me. The Taste of Thai brand says its regular coconut milk has 64 grams of fat per 14-ounce can. The light milk claims "only" 21 fat grams. Ah, but take a closer look: The ingredients listed for regular: "Coconut." The ingredients for light: "Coconut, Water." Since they cost about the same ($1.69). I think I'll stick with the regular - and add the water myself.

Party Animals

Giving new meaning to the phrase "lean government," it seems that the national move to the political right is being led by people who have little sympathy for fat. In a study reported in the Journal of Personality and Social Psychology, Christian Crandall of the University of Kansas says that Republican-types registered more distaste for plump people than did Democrats. He says that's because conservatives hold people more responsible for their own situations, including appearance and social status.