The answer must lie in the behavior of wild cats. We have all seen wild cats on television. They are carnivores and they don't change their diet according to their age or whether they are active or inactive.
The cat food manufacturers produce a range of food types to extend their range of products. In other words it's simply a matter or profit for the cat food manufacturer. An irritating point is that the cat food manufacturers state on the packet that a cat is a "Senior" cat when she is beyond the age of 7 or 8. This seems remarkably young to me. This may be to get more cats on the senior diet as it may be cheaper to produce (I'm probably being too cynical).
I am used to cats living to late teens. Some of the modern cat breeds, though, do have on average shorter lives, being less robust.
The difference between kitten and senior cat food is sometimes simply a matter of adding more carbohydrates and fiber in the senior food. I presume this is to aid digestion (the fiber - but this has no nutritional value) and provide more calories to boost activity. There is already too much carbohydrate content in cat food particularly dry cat food. Cats need an intake of high levels of protein, moderate levels of fat and low levels of carbohydrates. Fats should provide the calories not carbohydrates.
In short the inactive, old cat should ideally eat high protein cat food (wet food - dry food contains too much carbs) and take as much exercise as possible. A raw cat food diet, home prepared is acceptable, provided care is taken and supplements and roughage given.
- "Your Cat" by Elizabeth Hodgkins DVM
- top picture copyright and By Mel1st
- bottom picture copyright and By fofurasfelinas