Just got to get the job done? 9 kg in 30 days is roughly a KG every 3 days.

To burn 1 kg of fat requires roughly 7700 calories to be burnt. So, divide that by 3...

You're telling me you were in a caloric deficit of 2500 calories a day, for 30 days?

You ate basically nothing at all for 30 days? Do you know how much muscle you would lose?

Just to prove a point or something? Sure