So suggest the results of a study reported on by ScienceDaily. Ignore the standard bunkum about how incredibly fat-rich our diets are these days -- we've been heaving fat overboard for at least 30 years and replacing it with carbs (protein has stayed roughly the same). I'm happy that they snuck in the fact that dietary fat helps absorb vitamins -- something you never learned about in health class.
Note that the particular fat they found mechanistically involved in forming memories is oleic acid, the monounsaturated fat that makes up most of the fat content of olive oil. Every good Whole Foods shopper knows that olive oil is saintly, its contents above reproach. Well, let's take a look at the fat content of hamburger meat that is 75% lean (the fattiest you can find in most supermarkets). Scroll down to the box labeled "Fats & Fatty Acids" and click the "More details" tab to show how much of all the different types of fats there is.
Oleic acid is under monounsaturated, 18:1. What do you know -- oleic acid accounts for 39.1% of all fat! (5.471 g / 14 g.) Moreover, this fatty hamburger meat has more monounsaturated than saturated fat (and hardly any polyunsaturated fat), despite the anti-fat hysterics who make it sound like eating a quarter-pounder is tantamount to eating a quarter pound of butter. Nothing wrong with saturated fat, of course. And still, oleic acid makes up 24.5% of the fat content of butter!
The crucial difference between getting oleic acid from dead animals vs. olive oil is that you can easily eat a pound of hamburger meat a day, while you would gag eating anywhere close to that amount of olive oil. (And take it from someone who once swallowed 2 tablespoons of olive oil as an energy boost before I went out dancing.)
So if you're having trouble remembering things, do what I did this morning and have a 1/3 pound burger with a liberal amount of butter for breakfast. (Along with some Emmental cheese and spinach.) No better way to start the day!