The best real-life example: "Morning breath" which affects everyone upon waking up. During sleep, the flow of saliva is drastically reduced. Food residue and dead cells accumulate and get digested by an increasing number of bacteria and an unpleasant smell is generated.

Skipping your meals can cause bad breath in the form of a hunger odor, similar to "morning breath," which is accompanied by the sensation of hunger.

Fortunately, this "morning breath" generally disappears after food intake and after brushing the teeth because saliva starts to flow again and any left-over residues are washed away and swallowed.