39.Male 20kg overweight

Options
Being a ex martial artist I've always trained and been active. Over the past year I have been to busy working and have trained less so I gained a "healthy" 20kg. Now I want to loose weight. Feel better. I've already lost 3.3kg in the first week, but as u know it's always like that the first week. So what I'm asking for is any advice besides the norm, to help me loose weight tighten up and rip. My goal now is 18Kg in 18 weeks.

Any advice.