Can Cats Eat Pesto?
The short answer as to whether cats can eat pesto is no, absolutely not. If your feline friend accidentally licked a bit of pesto off the floor, then there is nothing to worry about, but we certainly don't advise letting them eat pesto regularly or in any great quantity.
Some pestos might be worse for your cat to eat than others
The first thing to acknowledge is that there's no "one size fits all" when it comes to pesto, simply because different producers use completely different ingredients. To keep things simple, the sauce we're discussing here is the most traditional of all: the classic basil pesto, which contains little more than olive oil, salt, pine nuts, cheese, garlic, and basil. Let's break the ingredients down one by one and see if they are safe for cats to eat.
The olive oil in pesto is fine 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 also lead to diarrhoea or vomiting if cats consume too much of it.
Cats need salt, but not as much as is in pesto
Scientists have different opinions on the safe level of salt that cats can have in their diets. Broadly speaking, though, there is a consensus that dried cat foods should contain no more than 0.2% salt. When you bear in mind that there are some pesto sauces on the market containing up to 5.1% salt, at those kinds of levels, there's a very real risk of poisoning your cat, which, if not treated, can ultimately lead to death.
Pine nuts are not toxic for cats but are often replaced by cheaper nuts
While some nuts (such as macadamia) are toxic to pets, pine nuts (which are seeds) are not toxic for cats to eat in moderation. The main problem comes when producers chase cost savings and replace the expensive pine nuts with cheaper alternatives. Always read the label.
There are a couple of other reasons to prevent your cat from eating nuts. Firstly, all nuts are high in fat, which means your furry friend might have problems digesting them. Perhaps even more important is that cats' teeth are designed for tearing, not chewing. That means they are likely to swallow nuts whole, which obviously poses a risk of choking.
Most cats can safely eat cheese, but yours might be intolerant
Traditional pesto contains both Parmesan and Pecorino, and while they are not toxic to cats, many cats are sensitive to lactose. This means that cheese can cause digestion issues, which can manifest in tummy aches, constipation, or worse.
Another important point is that cats are what's called obligate carnivores, which means their digestive system deals with meat well but not dairy. Cheese, therefore, has virtually no nutritional value for them, and while giving a cat a tiny piece of cheese as an occasional treat is widely considered safe, it's best avoided in any great quantity.
Pesto cannot be made without garlic, but the jury's out on whether it's safe for cats to eat it
Some animal nutritionists say garlic can be given to cats in very small quantities, while others recommend never letting it pass their lips due to the gastrointestinal issues that could result. We take the belt-and-braces approach and never feed garlic to cats.
Beware of other ingredients that may not be recommended for cats to eat
Many of the pesto sauces you see for sale in supermarkets contain completely different ingredients from the Pesto Genovese Consortium's official 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 your cat's ultimate food list, and if they've never tasted it, they'll never know what they're missing anyway. It's why, when we're asked if dogs can eat pesto, we also say it's just not worth the bother.