Do you know good way of diet?

I have to lose weight!! Please help me!! Have you lost weight? I have tried many ways but all failed!! Recently I gained 3kg. Oh my good!! But I can't stop eating. And I finished working late so I have dinner really late more and more. This is so big problem for me. I will go back to my hometown and I will meet my old friends. Certainly, they tell me that "did you gain weight?". I never hear that.