I think everybody who's into k-pop heard before this challenge.
What I'll do:

I will eat every day for breakfast an apple, for lunch (sweet) potato - because the sweet one is expensive in Hungary - and a protein shake (stawberry or vanilla) for dinner.

I'll cheat, because I need caffeine so I'll drink energy drink, not what I buy from the store, I make it by tablets.
And I cannot not drink tea. So I'll drink that too without sweeteners and lemon. I like mint and black teas.

I am 74 kg now (and 165cm). My goal is do it for 2 weeks. In this 2 weeks I know I'll eat sushi one day, because of my friends, and I'll eat 4 days rice, because the potato is very boring. I know I tried that once before.

I will write my daily routine in the focus of the diet.

If you have any questions just ask, I'll answer.