In her book "Gulp: Adventures on the Alimentary Canal," Mary Roach highlights the evolutionary adaptations of animals, illustrating that they have developed preferences for foods that best support their survival. This contrasts starkly with human perceptions of pet food ingredients, particularly the inclusion of fish meal or meat meal.

Many pet owners are uncomfortable with these ingredients, yet Rawson explains that meal, which can consist of various animal parts like organs and bones, actually reflects the natural diet of domestic dogs and cats. This connection to their wild ancestry emphasizes the importance of understanding animal nutrition from an evolutionary perspective.