First Lady Michelle Obama's "Let's Move!" campaign against childhood obesity got a big boost in Congress on Thursday, in the form of a letter signed by more than 1,100 groups that asks House members to immediately pass a childhood nutrition bill when they return next week. Signers include food, beverage and supermarket companies; public health, education, anti-hunger, faith-based, children's, women's, minority groups; and unions. They want the House to pass a $4.5 billion bill that cleared the Senate by unanimous consent just before the August recess.