A year ago, Michelle Obama and pupils from a Washington elementary school dug up a patch of the South Lawn to plant a White House vegetable garden. Mrs. Obama’s stated goal — apart from providing food for her family’s meals and for formal dinners — was to promote healthful, locally grown fruit and vegetables and healthier eating by kids at a time of rising rates of childhood obesity and diabetes.

Mrs. Obama has translated that into a serious national initiative to improve childhood nutrition and health. In appearances around the country, she has been talking about childhood obesity and engaging parents, schools, pediatricians, celebrities, and public officials, including members of her husband’s cabinet, with the goal of solving the problem within a generation.

Last month, Mrs. Obama began her “Let’s Move” campaign. Beyond encouraging greater physical activity by children, the Food and Drug Administration is trying to help parents make healthy food choices by making food labels more customer-friendly. The campaign includes $400 million to bring grocery stores offering fresh produce and other healthy food to underserved, often poor areas, and a planned nutritional upgrade of school lunches when Congress reauthorizes the Child Nutrition Act.

Recently, appearing before the Grocery Manufacturers Association, Mrs. Obama spoke with humor about her own experience as a mother trying to encourage healthy eating habits in her children, and praised food companies for some positive steps. But she also chided the industry for not going fast or far enough.

“We need you not just to tweak around the edges, but to entirely rethink the products that you’re offering, the information that you provide about these products, and how you market those products to our children,” Mrs. Obama said. “That starts with revamping, or ramping up, your efforts to reformulate your products, particularly those aimed at kids, so that they have less fat, salt, and sugar, and more of the nutrients that kids need.”

Mrs. Obama’s campaign is just beginning, but she has already started a national conversation on obesity.