The other day at work a woman came in with an overweight pug. She was easily convinced that it needed to lose weight, but didn't really know what she was doing wrong. Among other things she mentioned that the dog got one whole apple a day.
Now, an apple is not the highest calorie snack you can eat. But an apple is the size of this dog's whole head.
I would have thought it was obvious, but I guess it bears repeating: Unless you are a snake, do not eat anything as big as your head.