A team at Iwate University in Japan says the stubbornly half-empty bowls that puzzle many cat owners may have less to do with fullness and more to do with smell.
Led by Professor Masao Miyazaki, the team has been investigating why cats leave food uneaten. Unlike dogs, cats often eat small amounts multiple times a day and will stop eating even when still hungry. Some domestic cats may protest vocally if their food is served a few minutes late yet still leave a bowl half-finished once it is placed before them.
The researchers suggest that the scent of food holds crucial clues to this behavior, and that repeatedly serving the same meal can make a cat appear picky because the animal habituates to its smell, not because it becomes physiologically satiated, according to Gizmodo.
The study, published in the journal Science Direct, centered on how smell alone can determine a cat’s appetite. In controlled feeding experiments with twelve cats of different ages and genders, the team provided commercially available dry foods in a repeated cycle. Cats had 10 minutes of access to food followed by 10 minutes with an empty dish, repeated six times.
New stimuli
When cats received the same dry food in consecutive rounds, they gradually ate less over time, even if the food was among their favorites. The pattern held when cats were constantly exposed to the same meal’s odor between cycles, suggesting that odor-dependent habituation—rather than fullness—was dampening their motivation to keep eating.
By contrast, when different foods were provided in each of the six instances, the decrease in intake was mitigated and total consumption rose. A cat’s appetite also returned when it was offered the same food paired with a different scent. This underscored the central role of odor novelty. Variety in aroma alone could revive appetite and interest.
In one sequence, the same food was served five times in a row and then replaced with a different food on the sixth occasion. The amount eaten rebounded once the change was introduced. Even without switching the actual kibble, allowing the cats to smell a different food restored their appetite.
Professor Miyazaki explained the behavior as stemming from "boredom caused by eating the same food", saying appetite recovery is linked to "new stimuli,” according to Mainichi Shimbun.
What to do with obese cats?
Dietary variety could be used to encourage sick cats to eat more, leveraging novel odors or alternating foods to overcome olfactory habituation and restore appetite. Caretakers of obese cats might benefit from keeping meals consistent, using the same food and scent profile to limit intake.