CNN 's Val Willingham , Suzanne Malveaux , Alan Silverleib and Madison Park contributed to this report . NEW : Michelle Obama on ` ` Larry King Live '' : Small children can make a difference . First lady introduces national campaign to prevent obesity in children . President Obama signs memo establishing task force on childhood obesity . Number of overweight children has increased since 1970 , study finds .
NEW : Michelle Obama on ` ` Larry King Live '' : Small children can make a difference . First lady introduces national campaign to prevent obesity in children . President Obama signs memo establishing task force on childhood obesity . Number of overweight children has increased since 1970 , study finds .