The new garden book “American Grown” seems little different from all the other veggie-centric titles that crowd the shelves of horticultural titles these days.

The glossy pages track a newbie gardener’s efforts to grow her own food in the city and, true to form, the cover shows the author-gardener beaming radiantly and holding a basket heavy with produce.

But there, the similarity ends. The gardener is Michelle Obama, the home is the White House and the vegetable garden on the South Lawn has become so much more than just another city slicker’s gee-whiz carrot patch.

Four growing seasons after the Obamas carved out the beds in a corner of the greensward, the White House vegetable garden has developed as the symbolic crossroads of a range of contemporary societal issues, some connected, others less so.

Sustainable local agriculture, national farm policy, school gardens and, most of all, childhood nutrition and health have all found common ground in the garden. The book, written with Washington journalist Lyric Winik and others, and published in May by Crown Publishing, is full of photos and descriptions of the seasonal joy and delight of raising fruit and vegetables. But, on another plane, it reads as Michelle Obama’s personal manifesto.

The popular first lady seems so far to have successfully navigated the minefield of Washington politics, although some are grousing that she hasn’t done enough, while others worry that she has done too much. Her promotion of farmers markets and other local food systems is “profoundly mistaken,” said Pierre Desrochers, an associate professor of geography at the University of Toronto-Mississauga who is fed up with the dissing of big agriculture.

Yet others laud the first lady for bringing valuable visibility and traction to childhood nutrition, even if much more has to be done to achieve her goal of “solving the challenge of childhood obesity within a generation.” She has invited children from the District’s Bancroft and Harriet Tubman elementary schools to ceremonial plantings and harvests, organized a farmers market nearby on Vermont Avenue NW, and started an exercise campaign called Let’s Move! In addition to the public relations efforts, she has also been active in government policy and is credited, along with President Obama, with securing passage of the Healthy, Hunger-Free Kids Act of 2010. Currently, she is the nation’s representative at the ultimate keep-fit event, the Olympic Games in London.

Her efforts have “brought incredible energy to the people in the trenches working for a long time,” said Duane Perry, who founded the Food Trust, a Philadelphia nonprofit group established in 1992 to bring better food to the inner city. “There has been a [cultural] shift, which only something like a first lady on a personal level is likely to accomplish. The last time we saw something this significant was when Eleanor Roosevelt used her bully pulpit to effect change.”

A pernicious double-whammy

Even by American standards of mobility, Michelle Obama’s journey from the South Side of Chicago to 1600 Pennsylvania Ave. is remarkable. But in her book, she speaks of facing — along with everyone else — the pernicious double-whammy of modern life: a shift in food norms and a sedentary lifestyle that has made half the country’s population overweight or obese and, for the first time, created a generation of children with a shorter life expectancy than their parents.

Obesity rates have climbed dramatically over the past two to three decades. More than two-thirds of adults are overweight or obese. Almost a third of children are overweight or obese, and seven out of 10 overweight youths will become overweight or obese as adults, according to government data.

The direct health-care costs have been estimated at as much as $150 billion annually, and the phenomenon also plays out in lost productivity in the workplace and a threat to military preparedness. More than 40 percent of the Army’s applicants are overweight or obese. Michelle Obama writes that 50 percent of recruits cannot pass a basic fitness test, compared with just 10 percent five years earlier.

The first lady, through a spokeswoman, declined to be interviewed for this article. In her book, Obama says that she was motivated to take on the cause of childhood wellness when her children’s pediatrician raised the specter of their diet being poor. The Obamas have two daughters: Malia, 13, and Sasha, 10. The first lady is “politically astute, and yet the whole thing resonates with me as genuine,” said Parke Wilde, an associate professor at Tufts University’s Friedman School of Nutrition.

Shift in food and exercise norms

Obama, who is 48, tracks the shift in food and exercise norms through her experience as the daughter of a blue-collar African American family. A dash to McDonald’s just wasn’t part of her world. “My mother made iceberg lettuce salads and cooked broccoli, peas and carrots along with spaghetti and meatballs or lemon chicken. . . . No matter what she served, every dinner featured at least one vegetable. And we had to eat it, no exceptions.”

Exercise took the form of walking to school, playground recess and neighborhood games. Later, she would cycle around the city.

How times have changed. Michelle Obama and others portray an America where fewer children walk to school, physical education classes have been cut, kids constantly snack. Meals often consist of oversized portions of energy-dense food at chain restaurants. Soft drinks, the single biggest source of calories, have climbed in size from little more than six ounces in the 1960s to, typically, 20 ounces.

At pharmacies and even office supply and housewares stores, consumers and their children confront a gantlet of candy at the checkout.

“Right now, the food environment is almost perfectly designed to make us fat,” said Margo Wootan, director of nutrition policy at the Center for Science in the Public Interest. “Eating well is like swimming upstream. You can do it but it takes a lot of effort.”

Wootan applauds the first lady’s early efforts but says the administration now seems reluctant to implement legislation in key areas such as banning snack food and sodas in schools and requiring chain restaurants to list the caloric content of their meals. “The answer to addressing childhood obesity is not the first lady going on ‘David Letterman.’ That’s nice, but what going to make a big difference is getting junk food out of schools.”

But others say that is beginning to happen, in part because of Michelle Obama’s leadership. “People could quibble, you have to do more of that, less of that, but we really have an advocate for childhood obesity in the White House, getting the nation to think about it. She’s a fantastic ally,” said Gary Foster, director of the Center for Obesity Research and Education at Temple University.

“You could list a hundred things that should be done to address obesity, and the Obama administration is working on some but not all,” said Kelly Brownell, director of the Rudd Center for Food Policy and Obesity at Yale University. “When we go back and write the history of obesity, you will see what [the Obamas] are doing is sensitizing the nation for what the government can do later on.”

Changes to school programs

Foster said he is encouraged by the result of a 2008 study he co-authored that showed that even modest changes in school programs can have significant effects. He tracked more than 1,300 fourth- to sixth-graders in 10 public schools in Philadelphia. In half of the schools, most snacks and high-sugar beverages were removed and the students were given classes in healthy foods, with no such measures in the other schools. After two years in the schools focusing on nutrition, 7.5 percent of the students became overweight. In the schools with no intervention, twice as many students became overweight.

Alyssa Moles, the regional farm-to-school coordinator at the Food Trust, works with 32 public schools in Philadelphia to buy local produce and to teach food-service workers to prepare fresh fruits and vegetables — a program bolstered by the 2010 legislation Michelle Obama pushed. For Moles, a trained chef, this has meant something as basic as showing school kitchen staff members (who previously heated prepared foods) how to chop and cook raw vegetables.

The first lady’s involvement has established a national awareness of food and health that would have been years in coming without her, Moles said. “I don’t get e-mails any more that say, ‘Hey, what’s this farm-to-school thing?’ The conversation has switched to ‘How do we make it bigger?,’ and she has really advanced that conversation, especially with that garden on the White House grounds.”

Yael Lehmann, executive director of the Food Trust, says the first lady’s popularity — she has a 66 percent approval rating, according to a May poll by Gallup — has a significant bearing. “We are seeing a lot more gardens in schools, and people gardening in the neighborhoods; I think she’s a real inspiration,” Lehmann said. When children see her gardening and doing sports, “it makes them want to be like her.”

White House link to local food

Beyond its implicit nod to nutrition, the White House garden offers a literal link to the local food movement, which is integral to Michelle Obama’s diet and exercise initiatives. Her husband’s picks to head the Agriculture Department, Secretary Tom Vilsack and Deputy Secretary Kathleen Merrigan, have championed local agriculture, often working closely with Michelle Obama. In her book, the first lady writes that urban farms, community gardens, school gardens and farmers markets all offer a source of fruit and vegetables, especially in inner-city areas where grocery stores and access to fresh produce are scarce.

The garden “announced to everybody that this local and real food movement was no passing fancy,” said Bill McKibben, an author, environmentalist and scholar in residence at Middlebury College in Vermont. “It was so normal that the most iconic address in America was going to be a part of it.”

If the White House vegetable garden has delighted locavores, its goals are viewed more skeptically in food-policy circles. “I think the White House garden is a nice public relations move, but we are not going to garden our way out of this problem,” said Wootan, of the Center for Science in the Public Interest. “We can hardly get people to eat a carrot, much less grow it.”

There is also a backlash to the local food movement by supporters of big agriculture, who argue that the movement is a costly, feel-good distraction for urban elites while undermining the most efficient, economical and safe system of food production in history.

“If you want to embrace locally produced organic and nonprocessed food . . . you could move to sub-Saharan rural Africa,” write the University of Toronto-Mississauga’s Desrochers and public policy scholar Hiroko Shimizu in their new book, “The Locavore’s Dilemma.” “There, about 60 percent of the population is engaged in either farming or herding from dawn to dusk.”

Desrochers, in an interview, said that Shimizu, his wife, grew up in Japan, which is an island nation that relies on the importation of distant, mass-produced food for its diet. The Japanese are not known for their obesity, he said.

In promoting local, small-scale agriculture, “Mrs. Obama’s crusade is well intentioned but completely misses the mark,” Desrochers said. “We used to have small-scale farms and homesteads,” he said. “People were miserable; they were malnourished.”

But Yale’s Brownell said the cause of local food is connected to nourishment. “People care about different pieces of this, but when you add it all together, what you’re seeing is a social change, where people are caring about the story of their food. If you’re eating locally, where does a bag of Cheetos fit in?”

“We obviously can’t grow everything that we put on our tables ourselves,” writes the first lady. But she argues that gardens together can make a difference. The book features a food bank community garden in Winston-Salem, N.C., that harvests as much as 9,000 pounds of produce annually, and a network of gardens in impoverished Camden, N.J., that together raise half a million pounds of food on 25 acres. Roughly 10 percent of the city’s population gets some of its food from these gardens.

And in addition to the tangible benefits, Obama writes, gardens “bring individuals and communities together.”

The White House garden is “a wonderful, symbolic act,” said Peter Hatch, who recently retired as director of gardens and grounds at Monticello. “Actually, to me it’s more than symbolism.” Hatch gave the first lady seeds of varieties grown by Thomas Jefferson and has attended the ceremonial plantings of the White House garden. “If you dig your hand into the soil, you’ll see, it’s thriving with earthworms. I know people giggle that she has a big [gardening] staff and Michelle is a city girl. But if you judge a culture by the quality of its dirt, then what she’s doing is totally substantive,” he said.