Has anyone tried this 21 day diet/ challenge and does it work?

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I saw a post on fb that says for 21 days your supposed to have:
No candy
No cakes
No chips
No white bread
No fast food
No chocolate
No ice cream

Has anyone tried something like this? Did it work? How much did you lose? I know it will be hard for me bc i eat candy and chocolate every day lol ( a few pieces a day not bags). Let me know!