Im 22 and weigh 109 KG?

hey, just wondering what is the best why to loose my gut in a short time? i don't look like im carrying that weight but iam,i stopped going to gym 4 months ago because it shut down due to bankrupt know im so unmotivated!!! i have put on weight and i want to loose my gut before summer! i want to loose 20 kgs at least! so i have herd green tea works in regards to a diet program?