Michelle Obama seems to have found her mission as first lady, and it grew out of the planting the most famous vegetable garden in the world.
She hinted at what might become her cause last summer when she celebrated the garden's first harvest with the schoolchildren who helped her plant it. She declared that poor eating habits are a root cause of obesity, and obesity is a root cause of health problems that are taxing this country's resources: heart disease, high blood pressure and diabetes.
And she said that those grown-up diseases are showing up in children.
After almost a year of East Wing planning, she launched "Let's Move" this month. It is an ambitious initiative to end childhood obesity in a single generation. She's challenged food producers to reduce the sugar, salt and fat in the food they make, improve the labeling and stop targeting kids with their advertising. She's got a federal financial commitment to help build full-service grocery stores in the so-called food desserts in rural and inner-city areas where a gas station or convenience store is the only place to buy food.
She's got schools promising to improve lunches, soda makers removing soft drinks from school vending machines and professional athletes preaching to kids to get 60 minutes of exercise every day.
She's got critics, too, who are furious that the federal government would try to tell us what to eat and what to feed our children. Then there are others who point out that you can't feed your children much of anything if you don't have a job first. And still others who think she picked a softball to swing at.
But Michelle Obama, who is not only the mother of young children but also an African-American from a working-class family, is about the only person who could deliver a message so fraught with race and class issues and that challenges the sacred institution of parenthood.
Thirty percent of children in this country are overweight or obese, as measured by body mass index (BMI), and among black and Hispanic children that number is 50 percent.
Only a black mother, who freely confesses her own missteps in feeding her children, can deliver such a painful message to minority parents -- telling them that they are doing a poor job of feeding their kids -- and have any chance of being heard.
As if to illustrate the point, one of Mrs. Obama's first appearances on the stump for her new program was in Mississippi, a state with the highest obesity rate in the country, and in front of an audience of 1,000 PTA officials, almost all of whom were black.
She told them she made simple changes to get her family's weight and health back on track: no weekday television, smaller portions, less take-out food, skim milk or water in lunches and lots of fruit in the house.
She told them how surprised she was at the impact these small steps had. Her pediatrician asked, "What on earth did you do?"
Nancy Reagan said to say no to drugs. Barbara Bush said everyone should read more books.
Michelle Obama is being criticized for choosing a safe cause to champion: healthier eating.
But it wouldn't be a safe cause for a white first lady.
Susan Reimer's column appears Mondays.