Here's a little gem from an article on Buddhism. I choose it because of it's relation to food and our thoughts.
In our society, we spend a tremendous amount of energy controlling what goes into our bodies. We obsess about what’s in our food and where it’s grown and how it may or may not be healthy for us. If we are what we eat, we are also what we think. There’s no better metaphor for the thoughts in our brains than the modern supermarket, with aisle after aisle of both useful and superfluous items, various brands of almost exactly the same thing.
The effort of replacing negative thoughts with positive ones is like replacing an enormous bag of potato chips with a fresh peach. Instead of reaching for the thing I usually reach for when I’m ravenously hungry, which will only leave me feeling sluggish and gorged, I could reach for something less immediately desirable that will leave me feeling better in the long run.
I’m not accomplished enough to get out of the supermarket, but I can try to be more discriminating about what I put into the cart—what I chose for myself out of the endless inventory. I can reach for the peach, try as much as possible for the diet of joyful thoughts.