She already knows what the doctors will do on Monday. She tries to hold back telling people but lets it all slip out because she has no self control: diabetes, liver enlargement, etc. I suspect the meeting on Monday is just for them to go over everything they talked about over the phone and to give her information on what she should be eating. Maybe more tests.
She didn't want to tell the viewers now because she didn't want people giving her shit about what she is still eating. She figures she has the weekend to slam down a lot of crap food. So Monday she will be on another "diet". But for now, she can eat on camera and everyone should just shut the fuck up.
She is so resentful and angry even thinking about eating better. She talks sarcastically about carrots and oatmeal.
Ironically, if she had improved her eating a year ago, she might well be able to have fast food some times. But now, when death is calling, that is off the table, so to speak. They will probably want her on a super restrictive diet like Dr. Now's just to save her life in time. Wait for the incoming angry streams.