Will exercising alone be effective without managing my diet?

I desperately need to lose weight, but trying to manage my diet on my own is much harder than I expected and is causing me a lot of stress. I'm worried because my willpower keeps breaking down. Is it possible to lose some weight just by exercising consistently and diligently, without drastically restricting my diet?

I am really curious to know roughly what ratio you all stick to between diet and exercise when managing your weight loss. I would love to learn practical know-how and advice from those of you who have overcome diet-related stress or successfully lost weight! Please share your tips in the comments, no matter how small.