The pair have been in a relationship for some time, but Thursday night's episode will see Whitney finally tell Fatboy that she only sees him as a friend.
In contrast, Whitney has developed strong feelings for Tyler Moon (Tony Discipline) since his arrival on Albert Square last year.
However, McGarty told This Morning today: "As a viewer of EastEnders - and I love EastEnders, I've watched it for years - I would personally think that Whitney should go for Fatboy, just because he's so lovely and he genuinely cares.
"For Whitney to go with Tyler now is just a risk to take. She doesn't know where it's going to go."
McGarty said that Whitney's views on the love triangle are very different, as she feels she made a mistake by getting romantically involved with Fatboy (Ricky Norwood).
She explained: "I think Whitney loves him as a friend. I think she always loved him as a friend, but just got a bit confused after everything that had happened to her. She needed a shoulder to cry on."
EastEnders continues on Thursday at 7.30pm on BBC One.
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Watch Whitney's EastEnders character trail in the video below: