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Jose Luis Magana, Associated Press
First lady Michelle Obama speaks at the annual Building a Healthier Future 2015 summit in Washington, Thursday, Feb. 26, 2015.

WASHINGTON — Michelle Obama says the U.S. has seen a "culture change" in the five years since she started raising awareness about childhood obesity.

The first lady says food companies, fast-food restaurants and convenience stores are "racing like never before" to create and sell more nutritious food.

Schools are growing gardens and replacing pizza and tater tots with fresh produce and whole grains at lunch.

She even noted that the Georgetown University women's basketball team gave away kale to the first 100 people who attended a recent home game.

Mrs. Obama says none of this was happening before her initiative.

But she also said at the health summit Thursday in Washington that progress is "incredibly fragile."