weight loss

So I am 17 and I really unhappy with my weight. I want to be less so that when I look at myself I'm not disappointed. I went through a dark time were I ate to make myself feel better but I regret it. Anyone have any good workouts/diets that have help them lose weight? I wo of like to lose at least 40 so I can be back at where I was before. Any advice would help. Thank you so much!!!