Do you REALLY want advice and are you willing to read up on it and consider ideas that seem to go radically against what we are told for years about the "Calories in vs calorie out" myths that also ppl on this forum will inevitably present?
calories in v calories out is undeniably true, sorry but it is. have you ever seen fat people in countries with low food supply? :P
What people dont take into account is that people react differntly, some are super responders and will drop weight fast, some are non-responders and wont hardly lose weight at all.
You have to combine good food, with excersise and uping you muscle mass to increase your at rest calorie burn. things like max burst exercise can be good for increaseing vo2max and such but again its subject to individual responses
What is beign acknowledged more and more is that people react in vastly differnt ways to different things. Calorie in v calorie out will work, simple physics ensures it, whether its the most effective way for an individual to attain their goals is a differnt question altogether.
If you lost 13kg in a month, thats a dangerous and unsustainable amount of weight to lose, and any responsible health advisor would warn you against it.