To dream of dog food represents your thoughts or a situations that encourages a protective attitude. You may be trying to defend yourself against unpleasant feelings or trying very hard to stay upbeat. Something that increases the need for emotional self-defense.
Negatively, dog food can symbolize situations that encourage anger, viciousness towards others, or excessive sexual behavior. Conflict or sexual stimuli that's difficult to separate from.
Positively, dog food can symbolize situations that encourage you to stand up for yourself, be protective, or be prepared for potential difficulties.