Livingston -- a news anchor at CBS WKBT in Wisconsin -- arrived to L.A. this weekend to appear on the "Ellen" show ... where she'll explain why she fired back at a viewer who said she was a bad role model because she doesn't promote a healthy lifestyle.
Jennifer went on the air and blasted the guy ... admitting she is overweight but saying, "You don't know me. You are not a friend of mine. You are not a part of my family ... I am much more than a number on the scale."
But at LAX, Livingston told us she hopes her situation makes more people aware about the negative impact of bullying -- saying, "I just think it's a discussion that needs to happen across the country ... and I think it's one that hopefully I'm bringing to the forefront."