Earlier this month, Michael Pollan, the best-selling food-nature-science writer, could be spotted settling in for lunch at Vietnam Restaurant on 11th Street, which for a man in his position - on tour as the author of an "eater's manifesto" - is a bit like stepping into the batter's box.

He is about to turn 53 (next week), a tall, rangy fellow, loose-limbed to the point of seeming unhinged, his head shaven, jeans well-worn, his smile broad, engaging and frequent.

It is one thing to eat in your comfort zone. At home in Berkeley, Calif., where he teaches journalism, Pollan, his wife, the painter Judith Belzer, and 15-year-old son Isaac fix meals from farmers-market pickings: "If you've got garlic and olive oil," you can cook anything; 20 minutes and it's on the table.

Or on a whim there's Chez Panisse, the local-seasonal landmark, a bike ride right around the corner.

Maybe seafood, Pollan ventures at Vietnam. Or maybe not: "Why don't you order?" he asks his companion.

On a book tour, all the usual bets are off; the eating is situational. The night before he'd had a catered pork tenderloin and chutney sandwich ("delicious") on the train from Washington.

That morning he'd had local ham and eggs at a book event at the White Dog Cafe. Who knew what they'd feed him at the Rose Tattoo before his lecture to an overflow crowd that evening at the Free Library?

He is on a no-breaks schedule, talks and interviews and lectures. People magazine calls during his hour of free time: "I'm taking a vow of silence after this," he says.

His new book,

In Defense of Food

, offers advice on ways to negotiate the toxic food environment - avoid food "products" that make health claims, shop the whole-foods periphery of the supermarket, don't eat anything your great-grandmother wouldn't recognize as food.

It is a thoughtful, if modest, sequel to his masterful

The Omnivore's Dilemma: A Natural History of Four Meals

, in which he inventories, among other things, the depredations of a plague of cheap corn - the fat of the Earth - and the double-cross of "industrial organics."

It fairly begged for this follow-up: Reeling with despair, his readers wondered what the heck (if not feedlot beef, factory-raised chicken, long-haul pork) they


in good conscience put in their mouths.

A big bowl of red-brothed, Vietnamese lemongrass soup descends, hot and savory and full of noodles. And then a barbecue platter of appetizers - grilled, marinated chicken, skewers of stuffed grape leaves, crunchy spring rolls, along with filmy rice paper and lettuce leaves to wrap them in, and sweet vinegar for dipping.

Michael Pollan has at it, curious about the dipping sauces, mystified at first by the crinkle-cut


, a radish rendered in the scary shape of a French fry.

But, as he writes, food is not just about health consquences. It's about pleasure, too, and community.

In that spirit, he does not belabor the uncertain origin of the chicken.

Or the ground pork.

Or the lettuce, which from the looks of it was not procured at a farmers market.

He is, instead, eagerly


his lunch.

Afterward, he takes a stroll around the Reading Terminal Market before heading to a radio-show taping.

He buys a Macintosh apple at the Fair Food Farmstand, has them wash it, and polishes it off - approvingly - for dessert.

On the Side:

Update on Hormones and Milk Labeling

In last week's "On the Side" column, I took issue with the Pennsylvania agriculture department's move to strip milk cartons of certain labeling claims, in particular a notice that the milk in some cases was produced without synthetic growth hormones. Apparently, so did Gov. Rendell's office. Responding to a flood of consumer complaints that had been building for months, the governor stepped in, and on Jan. 17 the department reversed course. Henceforth labels will be allowed to do what they've done all along - inform customers if the milk is from cows that are not treated with artificial hormones, also called rBGH.

In another note, the column erred in saying that Rutter's Dairy in York charged a premium for milk from untreated cows; it does not. It sells at the state's minimum allowable price. (In its own stores that was $3.88 a gallon for whole milk this month.)

- Rick Nichols

Contact columnist Rick Nichols at 215-854-2715 or rnichols@phillynews.com. Read his recent work at http://go.