First lady Michelle Obama is touring the country to promote her “Let’s Move!” campaign to end childhood obesity, and the White House has touted her initiative as having a direct impact on the health of America’s youth.

A press release announcing the first lady’s tour noted:

Mrs. Obama launched Let’s Move! on February 9, 2010 to unite the country around our kids’ health and create real support for families to live healthier lives… Thanks to these efforts, families now have access to more information to make healthier decisions for their children. Young people now have more opportunities for physical activity in their communities. Food in schools has been dramatically improved. More Americans now have access to healthy, affordable food closer to home. And the national childhood obesity rate has leveled off, and even declined in some cities and states.

The first lady also credited Let’s Move! for reducing obesity during her appearance on Good Morning America, which aired Tuesday. She told Robin Roberts:

We’ve really changed the conversation in this country. When we started, there were a lot of people in this country who would have never thought that childhood obesity was a health crisis. But now we’re starting to see some movement on this issue. Our kids are eating better at school. They’re moving more. And we’re starting…to see a change in the trends. We’re starting to see rates of obesity coming down like never before.

The White House similarly credited her campaign, citing a study from the Robert Wood Johnson Foundation that shows a decline in childhood obesity in several areas, including Mississippi, Philadelphia, New York City and California, “in recent years.”

The problem, as the Weekly Standard notes today, is that the study shows the decline in childhood obesity began well before the first lady launched Let’s Move! in 2010.

In Mississippi, the 13 percent drop in childhood obesity Obama noted began in 2005, measured through the spring of 2011. Philadelphia saw a 4.7 percent drop between the 2006-07 school year and the 2009-2010 school year, ending when Let’s Move! started. And in New York City, the data shows a 5.5 percent drop in childhood obesity between the 2006-07 school year and 2010-11 school year.

The study does credit the availability of healthy food and an increase in physical activity as the reason for lower obesity rates, and those are the central causes of Let’s Move!. But the statistics quoted by the White House do not back the first lady’s claim that her program has been directly involved in that success.