On the Googling recommendation: In this case this would yield various awful answers from MD’s and PhD’s that would sound good but aren’t.
As Mr Black was saying, the modern diet tends to yield too much linoleic acid from vegetable oils.
Corn oil, peanut oil, and sunflower oil are particularly severe offenders.
You would have to eat a truly vast and completely impractical amount of corn to get the amount of corn oil into your system that agribusiness can accomplish in a single bag of a snack or a single teaspoon out of a bottle of oil.
When one reads about the benefits of “polyunsaturated oils” this is pure ignorance – regardless of doctorates held – and one should immediately cast extreme doubt on everything that is said by that person, at least on the subject of oils. It is equivalent to touting the benefits of “liquids.” Just as not every liquid has the same properties and therefore they should not be lumped together with regards to being nutritionally desirable or as to what quantities should be consumed, the same is true of polyunsaturated fats.
Canola oil is not as bad an offender as many oils. High oleic canola is no offender at all, nor is high-oleic sunflower.
Oils from nuts are generally fine. (Peanuts are legumes.)
And all of this is dependent upon quantity. A modest amount of any of the high-linoleic oils, if the rest of the diet isn’t overloaded with that fatty acid, is perfectly okay. For example, if intake of peanut butter is anything reasonable and the rest of the diet is good, there’s no problem here. Or if overall intake is reasonable, the fact that a given meal was cooked with corn oil or sunflower oil is no problem.
Most would I think do well to cut back on inadvertent high intake of high-linoleic oils.
In contrast, oils high in monounsaturated fat such as olive oil or various high-oleic oils are very desirable, as is coconut oil – not for monounsaturated fats but for some desirable saturated fats that it contains.