After Dr. Will Clower got his doctorate in neuroscience from Emory University in Atlanta in 1997, he spent two years doing research at the Institute for Cognitive Sciences in Lyon, France.

While he was in France's third largest city, Dr. Clower noticed that very few of the French men and women he met were overweight, even though they ate yummy-tasting food.

"All of the rules we feel are going to keep us thin and healthy they break," Dr. Clower said. "They don't avoid carbs or fats. They eat late at night. They don't belong to gyms."

The French remain thin despite eating foods such as cheese and croissants and foie gras because they eat rich food in moderation. And though they don't make a fetish of exercise, they're very active, Dr. Clower said.

"They do a lot of walking. Many ride bicycles to work. They don't sit in front of a television for four hours a day," he said.

The Thunderhead Alliance, an Arizona based nonprofit which promotes cycling as transportation, released a study Aug. 29 that blamed the surge in obesity in the United States largely on the decline in walking and cycling in America since the 1960s. According to data taken from U.S. Census surveys, the amount of walking and bicycling by Americans has declined 67 percent since 1960, while obesity has increased by 241 percent.

As a neuroscientist, Dr. Clower, 43, an Alabama native who now lives in Forest Hills, has studied the cultural habits that lead to good health or poor health, how they are formed, and how they can be altered.

"Our cultural understanding makes decisions for us that we're unaware of," he said.

One reason the French are not fat is that eating is too important to them to be an afterthought, Dr. Clower said.

"They don't eat out of a sack as they're walking back to their desk," he said. "You don't see cup holders in French cars."

"What we focus on here is what we eat," Dr. Clower said. "How we eat is important, too. Their behavior habits control their portions for them."

The French preference for wine and the American preference for beer is another reason why we're fat and they're not, he said.

"Beer you can gulp and guzzle," Dr. Clower said. "Wine you have to sip. That helps control portions."

Our impatience, and the American cultural imperative that more is better also add to our waistlines.

The French take much longer to eat their meals than we do, but consume less during them.

"Restaurants, with their ever larger portions, are a big problem," he said.

Dr. Clower has written a book: "Fat Fallacy: The French Diet Secrets to Permanent Weight Loss."

Dr. Clower will expound on those secrets during an eight-week program hosted by Venture Outdoors, a nonprofit organization that promotes outdoor activities in southwestern Pennsylvania.

The program, titled "Hiking the Path," starts Saturday at the Three Rivers Rowing Association's boathouse in Millvale. Each program will consist of a lecture by Dr. Clower, followed by hiking or biking along area rail trails, or paddling on the Allegheny in a kayak or a dragon boat. Each session will run from 9:30 to 11 a.m. The cost of the program is $160. For more information, call 412-255-0564, or visit www.ventureoutdoors.org.

And each Monday evening beginning Sept. 10, Dr. Clower will expound on the Mediterranean approach to lower weight at Enrico's Ristorante in Shadyside. Chef Jason Sicher will prepare recipes from Dr. Clower's book. In between courses, Dr. Clower will talk about healthy eating habits.

The inaugural menu will feature a root vegetable salad with goat cheese, followed by beef medallions and roasted shallots, accompanied by a fresh pappardelle (large fetuccine noodles), summer squash, roasted tomatoes and caramelized leeks. For reservations, call 412-661-1050.