Here is the item again:
After Deidre saw the tiny balance on her ATM
receipt,
(A) she
realized,
(B) that
her meals for the next week would consist of cheap
food,
(C) such
as peanut butter sandwiches and instant soup.
You recognized that the comma after realized was wrong. That her meals for the next week would consist ... is a subordinate clause. When you attach a subordinate clause to the end of a main clause, you usually need no punctuation.
To fix this problem, you chose to do this:
After Deidre saw the tiny balance on her ATM receipt,
she realized that her meals for the next week
would consist of cheap food, such as peanut
butter sandwiches and instant soup.
You have correctly employed Punctuation Rule 1:
Main Clause + Ø + Subordinate Clause.
Excellent choice!