On the cover of her new book, American Grown: The Story of the White House Kitchen Garden and Gardens Across America, Michelle Obama is smiling into the camera and holding a huge basket of vegetables, the bounty of a garden planted, she writes, as “a starting point for something bigger.” That something bigger is the first lady’s campaign to get Americans — and especially children — thinking differently about what they eat. And behind the pride in her eyes is something a little trickier, a sly nod to the fact that for the past three years, she’s been getting a lot of kids to eat their vegetables.

It’s a challenge Jon Stewart summed up best recently when the first lady appeared on the Daily Show to promote her book. He asked, “Wouldn’t you have been more successful with, say, colonization of Mars?” She laughed at the question, but, in the book, she makes it clear that she takes this impossible mission very seriously.

American Grown chronicles the development of the White House Kitchen Garden — the first planted on the White House lawn since Eleanor Roosevelt’s World War II victory garden. The story begins in March 2009, when the first lady broke ground with 23 fifth graders, and follows the garden through four seasons of growth and harvest. It also includes garden plans, composting and beekeeping tips, recipes, and of course, many photographs of the first lady surrounded by children, who appear — believe it or not — to be enjoying gardening and eating the fruits (and vegetables) of their labor.

Lest this sound too upbeat, the first lady also makes the problem she’s looking to address very clear. Not only are one in three of our nation’s children obese, she tells readers, but a recent study of 200 overweight children found that more than half were overweight before they turned 2. On the other side of the age spectrum, she writes that obesity in young adults may even impact our national security, as it is becoming one of the most common disqualifiers for military service.

The book includes a short essay by Lt. Gen. Mark Hertlin, who ties poor diet and not enough exercise to rising injuries and health costs for the Army. Regarding new recruits’ fitness levels, he writes:

[W]hile in 2004, only 4 percent of male recruits and 10.5 percent of female recruits failed the Army’s Entry Physical Fitness Test (which requires one minute of push-ups, one minute of sit-ups, and a one-mile run), by 2010 those numbers had exploded: 46.7 percent of males and 54.6 percent of females were failing the exact same test.

Hertlin acknowledges that basic training puts soldiers back in shape, but voices concern for the health of the soldier’s family. He asks, “How do we change our behavior and our culture before it contributes to early onset of diabetes, coronary disease, osteoporosis, and even psychological difficulties? How do we do this before it is truly too late?”

Beyond advocating for simply making healthier personal choices, American Grown points to grassroots community efforts as a solution. Michelle Obama’s Let’s Move Salad Bars 2 Schools initiative is one — a grassroots public health effort that aims to place 6,000 salad bars in schools. The book also profiles five community gardens throughout the United States — from the P-Patch network in Seattle to a community garden in New Jersey. The book also includes contributions from leaders working to provide healthier food with greater community access, such as Growing Power, the urban farming and educational training organization, and Fresh Moves, a mobile produce market.

Outside the grassroots realm, the first lady has less to say. She was an active force behind the 2010 Healthy, Hunger-Free Kids Act, which added more funding and improved food standards of the National School Lunch program for the first time in 30 years. She also applauded when the U.S. Department of Agriculture launched the MyPlate/MiPlato initiative, urging Americans to get half their calories from fruits and vegetables.

And while the first lady began the Let’s Move campaign with a strong critique of the nation’s big processed food makers — telling them it was time to “step it up” and cut sugar, salt, and fat in 2010 — her tone has recently changed.

In fact, near the end of last year, she announced that she would be focusing on promoting exercise instead — a move that has been criticized as a clear choice to back away from food industry lobbying in an election year. A recent Reuters investigation called “How Washington went soft on childhood obesity” described the shift like so:

Kelly D. Brownell, a Yale professor and director of the Rudd Center for Food Policy and Obesity, said he believes the First Lady has become too friendly with industry even as she has been a passionate, effective advocate for healthier food and exercise. He pointed to the possible influence of a 2010 Supreme Court decision, criticized by the president, that removed limits on corporate and union campaign spending.

“It does seem that there’s been a shift in priorities in the Let’s Move campaign in an election year,” Brownell said. “And with the Citizens United case and the companies being able to lobby almost without limit, it’s not surprising that the White House is more friendly toward the industry.”

[Margo Wootan, director of nutrition policy at the Center for Science in the Public Interest], had a similar view: “I’d focus more on exercise, too, if my husband was up for re-election.”

American Grown does a similar job of staying away from the hard topics. As you would guess, there are no surprises here. But that doesn’t make the first lady — or the book, for that matter — unlikable. Her description of the lengths she’s willing to go to meet her Let’s Move campaign goals are inspiring, if apolitical. For instance, when she addresses the Let’s Move exercise campaign, she writes:

I’ve hula-hooped and done push-ups on the White House lawn. I’ve jumped Double Dutch and run through an obstacle course of cardboard boxes carrying water jugs. I’ve potato-sack raced with comedian Jimmy Fallon. I’ve even danced “the Dougie” to Beyonce with a bunch of middle schoolers. But there’s a method to my madness … I’m pretty much willing to make a complete fool of myself if that’s what it takes.

And it looks like it’s working; the majority of Americans seem to like the first lady’s hula-hooping, vegetable-peddling ways. According to a recent Washington Post-ABC News poll, Michelle Obama enjoys a 69 percent approval rating compared to her husband’s 56 percent.

The other night on his show, Jon Stewart likened the first lady’s popularity with the American public to ice cream, while he said the president’s was “more like astronaut ice cream.” The first lady corrected Stewart, in a subtle endorsement with a double meaning. “He’s vegetables,” she said.