It's not really true - at the physiological level, I certainly cannot see how prolonged consumption of processed food could disable a cat from being able to digest natural food. However, I could see the trace element of truth in this statement's essence, which might explain it's plausible origin.

Cats, compared to dogs, are known to be a bit of picky eaters. Unlike dogs, cats could literally starve themselves to death in case of the available food not suiting their fancy - that's how picky they could be. At the same time, please take into account that it's in the cat food manufacturers' best interest to make their products as tasty as possible, and they certainly have all the necessary means to do the research and come up with the optimal formula.

As a result, transitioning from processed cat food to natural food could in a way resemble - apologies for not coming up with a better analogy - transitioning a child's diet from prolonged dining in fancy restaurants and eating pizzas with a whole variety of alluring flavors, to unseasoned and blandly-tasting homemade food. The child would surely be resistant and need some time to transition - which, as other answers already mentioned, is the case in all diet changes - but it doesn't mean that the child's physiology and metabolism had been changed in a way that disabled them from digesting natural food. Like the child in this hypothetical scenario, a cat could just get psychologically used to a certain kind of tasty food, forming a deeply-rooted habit.

My analogy to human diet is obviously not the best and it's not directly one-to-one - yes, cat food manufacturers don't enhance flavor by using spices known in human cuisine, like black pepper, chili, onion, garlic, etc. Not only cats experience taste differently from humans, but also some of the human cuisine spices are extremely toxic to cats.

But my point still stands; as Trond Hansen noted in the comment, cat food manufacturers are using flavor enhancers, known as palatants, which could be seen as analogs of spices used in our human cuisine. Also, manufacturers do in fact research for the optimal texture, humidity, salinity, tenderness, etc. of the food to suit cats' fancy as much as they can. A cat used to this kind of food could just have been in some sense addicted to a great taste (addicted in the sense of psychological habit, not physiological dependency, though) - together with the before-mentioned cats' pickiness, attempts of such diet transition could give the convincing, albeit completely false impression of their inability to eat natural food ever again.

It's not really true - at the physiological level, I certainly cannot see how prolonged consumption of processed food could disable a cat from being able to digest natural food. However, I could see the trace element of truth in this statement's essence, which might explain it's plausible origin.

Cats, compared to dogs, are known to be a bit of picky eaters. Unlike dogs, cats could literally starve themselves to death in case of the available food not suiting their fancy - that's how picky they could be^*. At the same time, please take into account that it's in the cat food manufacturers' best interest to make their products as tasty as possible, and they certainly have all the necessary means to do the research and come up with the optimal formula.

As a result, transitioning from processed cat food to natural food could in a way resemble - apologies for not coming up with a better analogy - transitioning a child's diet from prolonged dining in fancy restaurants and eating pizzas with a whole variety of alluring flavors, to unseasoned and blandly-tasting homemade food. The child would surely be resistant and need some time to transition - which, as other answers already mentioned, is the case in all diet changes - but it doesn't mean that the child's physiology and metabolism had been changed in a way that disabled them from digesting natural food. Like the child in this hypothetical scenario, a cat could just get psychologically used to a certain kind of tasty food, forming a deeply-rooted habit.

My analogy to human diet is obviously not the best and it's not directly one-to-one - yes, cat food manufacturers don't enhance flavor by using spices known in human cuisine, like black pepper, chili, onion, garlic, etc. Not only cats experience taste differently from humans, but also some of the human cuisine spices are extremely toxic to cats.

But my point still stands; as Trond Hansen noted in the comment, cat food manufacturers are using flavor enhancers, known as palatants, which could be seen as analogs of spices used in our human cuisine. Also, manufacturers do in fact research for the optimal texture, humidity, salinity, tenderness, etc. of the food to suit cats' fancy as much as they can. A cat used to this kind of food could just have been in some sense addicted to a great taste (addicted in the sense of psychological habit, not physiological dependency, though) - together with the before-mentioned cats' pickiness, attempts of such diet transition could give the convincing, albeit completely false impression of their inability to eat natural food ever again.

References to the statement marked with asterisk:

• feline hepatic lipidosis article on Wikipedia;
• article on twocrazycatladies.com;
• article on pets.thenest.com;
• article on feline-nutrition.org.

It's not really true - at the physiological level, I certainly cannot see how prolonged consumption of processed food could disable a cat from being able to digest natural food. However, I could see the trace element of truth in this statement's essence, which might explain it's plausible origin.

Cats, compared to dogs, are known to be a bit of picky eaters. Unlike dogs, cats could literally starve themselves to death in case of the available food not suiting their fancy - that's how picky they could be. At the same time, please take into account that it's in the cat food manufacturers' best interest to make their products as tasty as possible, and they certainly have all the necessary means to do the research and come up with the optimal formula.

As a result, transitioning from processed cat food to natural food could in a way resemble - apologies for not coming up with a better analogy - transitioning a child's diet from prolonged dining in fancy restaurants and eating pizzas with a whole variety of alluring flavors, to natural homemade food. The child would surely be resistant and need some time to transition - which, as other answers already mentioned, is the case in all diet changes - but it doesn't mean that the child's physiology and metabolism had been changed in a way that disabled them from digesting natural food. Like the child in this hypothetical scenario, a cat could just get psychologically used to a certain kind of tasty food, forming a deeply-rooted habit.

My analogy to human diet is obviously not the best - yes, cat food manufacturers don't use flavor enchances in the form of spices known in human diet. Also, cats don't even experience taste the way humans do.

But my point still stands; cat food manufacturers do in fact research for the optimal texture, humidity, softness, etc. to suit cats' fancy as much as they can. A cat used to this kind of food could just have been in some sense addicted to a great taste (addicted in psychological, not physiological sense, though) - together with the beforementioned cats' pickiness, attempts of such diet transition could have given the convincing, albeit completely false impression of their inability to eat natural food ever again.

It's not really true - at the physiological level, I certainly cannot see how prolonged consumption of processed food could disable a cat from being able to digest natural food. However, I could see the trace element of truth in this statement's essence, which might explain it's plausible origin.

Cats, compared to dogs, are known to be a bit of picky eaters. Unlike dogs, cats could literally starve themselves to death in case of the available food not suiting their fancy - that's how picky they could be. At the same time, please take into account that it's in the cat food manufacturers' best interest to make their products as tasty as possible, and they certainly have all the necessary means to do the research and come up with the optimal formula.

As a result, transitioning from processed cat food to natural food could in a way resemble - apologies for not coming up with a better analogy - transitioning a child's diet from prolonged dining in fancy restaurants and eating pizzas with a whole variety of alluring flavors, to unseasoned and blandly-tasting homemade food. The child would surely be resistant and need some time to transition - which, as other answers already mentioned, is the case in all diet changes - but it doesn't mean that the child's physiology and metabolism had been changed in a way that disabled them from digesting natural food. Like the child in this hypothetical scenario, a cat could just get psychologically used to a certain kind of tasty food, forming a deeply-rooted habit.

My analogy to human diet is obviously not the best and it's not directly one-to-one - yes, cat food manufacturers don't enhance flavor by using spices known in human cuisine, like black pepper, chili, onion, garlic, etc. Not only cats experience taste differently from humans, but also some of the human cuisine spices are extremely toxic to cats.

But my point still stands; as Trond Hansen noted in the comment, cat food manufacturers are using flavor enhancers, known as palatants, which could be seen as analogs of spices used in our human cuisine. Also, manufacturers do in fact research for the optimal texture, humidity, salinity, tenderness, etc. of the food to suit cats' fancy as much as they can. A cat used to this kind of food could just have been in some sense addicted to a great taste (addicted in the sense of psychological habit, not physiological dependency, though) - together with the before-mentioned cats' pickiness, attempts of such diet transition could give the convincing, albeit completely false impression of their inability to eat natural food ever again.