Can Cats Eat Pesto?
No, do not under any circumstances feed pesto to cats.
The first thing to acknowledge is that there's no "one size fits all" when it comes to pesto. With dozens of different versions available - some containing unusual ingredients such beetroot, cauliflower and even cured meat - the only way to have any kind of confidence is to meticulously read the labels of any product that hasn't specifically been designed with pets in mind.
Having said that, when most people hear the word "pesto" they immediately think of the traditional basil pesto which is made from olive oil, salt, pine nuts, cheese, garlic and of course, basil. Lets break these ingredients down one by one and see how safe they are for cats to eat.
There are no issues with cats consuming olive oil per se. Just like humans, pets need a healthy amount of fat in their diet, not just for energy but for the essential fatty acids that they contain. However, excessive fat can not only lead to weight gain, but it can lead to diarrhoea or vomiting if cats consume too much of it.
Depending which research paper you buy into, scientists have different opinions on the safe level of salt that cats can have in their diets. Broadly speaking though, there's consensus that dried cat foods should contain no more than 0.2% salt. When you bear in mind that there are some pestos on the market containing up to 3% salt - at those kind of levels there's a very real risk of poisoning your cat which, if not treated, can ultimately lead to death.
Whilst some nuts such as macadamia are toxic to pets, pine nuts (which are actually a seed) are not toxic for for cats to eat in moderation. We don't really advise it though. Their high fat content means your furry friend is likely to have problems digesting them. The other thing to bear in mind is that cats' teeth are designed for tearing, not chewing. That means they are likely to swallow pine nuts whole which obviously poses a choking risk.
Traditional pesto contains both Parmesan and Pecorino, and whilst they are not toxic to cats, many cats are particularly sensitive to lactose. This means that cheese can cause digestion issues which can manifest in tummy ache, constipation or worse.
Another important point is that cats are what's called obligate carnivores which means their digestive system deals with meat really well, but not dairy. Cheese therefore, has virtually no nutritional value for them - and whilst giving a cat a tiny piece of cheese as an occasional treat is widely considered fine, it's best avoided in any quantity.
The jury's out on whether cats can eat garlic. Some animal nutritionists say it can be given in very small quantities, whilst others recommend never letting it pass their lips due to the gastrointestinal issues which could result. We take the belt and braces approach and never feed garlic to cats.
This is just about the only pesto ingredient that we feel comfortable feeding to cats, but even then only in moderation.
As we said in the intro, many pesto sauces contain completely different ingredients than the seven that are outlined in the authentic, traditional pesto recipe. This additional complexity means each sauce should be judged on a case-by-case basis. Quite honestly though, it's simply not worth the effort. The chances are pesto is very low down on cats' ultimate food list, and if they've never tasted it they'll never know what they're missing anyway.