Will Clower is tall and reed-thin with a ready smile that shows his perfect teeth. He is fit and friendly, a man in whom it's easy to put your trust.

		More information To inquire about classes: 1-800-994-7284. "The Fat Fallacy" ($13.95 paperback) is published by Three Rivers Press.

Although he has written the book "The Fat Fallacy: The French Diet Secrets to Permanent Weight Loss," I've just had lunch with him, and I am in a position to say that he really eats. He finishes what's on his plate and follows it with the right question: "What's for dessert?" It's on my mind, and I'm glad that it's on his.

Sitting on the balcony at Buon Giorno restaurant on Smithfield Street, we call down to owner Louis Martorella and ask which of four cheesecakes is his favorite. We share that one.

It's a rule of Clower's that sharing is a good thing. His diet is permissive, but there are rules: Allow yourself dessert only if you are not already full from lunch or dinner. Think ahead and prepare for dessert during the meal by eating smaller portions.

To begin your diet the Clower way, remember this rule: "If it's not food, don't eat it." Meaning: "If it's processed, don't eat it."

"What I'm advocating," he says, "is no faux food."

In his lexicon, Butterfingers are faux. Cool Whip is, too. Cheez-Its are not food. Partially hydrogenated oils are processed and therefore not acceptable. High-fructose corn syrup is a "no." He positively pales at the thought of food dyes such as red No. 40, blue No. 1 and yellow No. 6 used to produce, as he says, "big, fat, flaming faux foods." Sodas are not a food. As he points out, "It never grew. It has no mommy or daddy."

Clower, who lives in Forest Hills, is a neurophysiologist and a neuroscience historian. His Ph.D. is from Emory University in Atlanta. He spent two years as a research fellow at the Institute of Cognitive Sciences in Lyon, France, where the absence of long aisles of sodas and chips in supermarkets struck him as significant. Observing the skinny French who live longer than we do (two years longer for men, three years for women), he codified his theory of why they are thin and healthy by comparing their diet to his own. His conclusions resulted in his book.

At present, he is working on enterprises related to the book. One is a KQV radio show sponsored by Pennsylvania Macaroni Co., whose president, David Sunseri, lost 15 pounds in three weeks on the diet; others are teaching classes and providing an online course.

In his book and in person, he has plenty of advice that you can watch him practice during mealtime. He puts small amounts of food on his fork. Questioned, he says none should be bigger than the last joint of the person's thumb. He finishes chewing before taking another bite. He puts his fork down on the plate while he finishes chewing and before he takes another bite. There is a rhythm to it.

He pays attention, he says, to signals from his body that say it's satisfied. It's his theory that eating too quickly makes you fat for two reasons: First, the signal that you are full is delayed, and, because of it, your appetite keeps adapting to larger amounts.

Clower stops when he's satisfied. On the other hand, sitting next to him, I eat with both hands, slurping soup, asking questions, writing down answers and buttering my bread, all at the same time. Not pretty and an example of the stressful eating that Clower blames on our society's preoccupation with trying "to squeeze a few more minutes out of the work day."

While against eating fast, he's for eating well. To him, that means as high on the food chain as you can afford. Organic is preferred. What we eat and how we eat, weight loss and good health all are Clower's concerns. His principles are laid out in his book "The Fat Fallacy," written, he says, to provide a dietary cultural comparison.

The book is used as a reference in the eight-week classes on the Mediterranean Diet he's teaching at Citizens Bank and Robert Morris University. He calls the series "The Path."