Ramblings: what is it about depression and chocolate?

I have a confession to make. I love chocolate. Sometimes I believe I will never be able to loose weight because I love chocolate more than I like the idea of loosing weight. I know I am healthy because I exercise, but whatever good I do to myself, I mess it up with my sick, lust for chocolate.
Mind you, I hate white chocolate. I believe that is just the fat you get from the chocolate with a hint of the taste. I look at it and I think it looks nasty and I can't eat it. I wish I could trick my mind to feel the same way about regular chocolate. But I am unable to resist the temptation. And don't get me started on dark chocolate... sinful.
The best time to enjoy chocolate is when I feel sad. What is it about chocolate and depression that your body automatically craves it when you are feeling sad? If someone can find the answer to this question, they will probably make millions, since I am not the only one with this connection.
Now I go to bed in order to avoid the chocolate in the refrigerator. Keep trying.