> Hopefully in a month I'll have lost this weight
I think it's important to have realistic expectations here - 20kg in a month is a massive weight loss, and you're setting yourself up for failure if that's your goal. Even 5kg in a month is a lot.
A far more realistic and attainable goal is 1-2kg a month.
(Don't use The Biggest Loser as a guide to how much weight you can drop in a week!)