I added mct oil to my diet a month or so ago.
MCT oil is just a liquid fat like olive oil. It is tasteless but adds a nice mouth feel to coffee.
I think that there is way too much hype around it. It ‘could’ improve brain function but that would depend largely on what else you are eating. If your brain already works well, then adding a bit of MCT oil wont really change anything.
MCT oil has been used for years as a mild laxative. When used as a laxative is it given 4 tables spoons a day. So if there was much evidence that 1 tablespoon in a coffee helped your brain function, Drs would be on top of this as a miracle cure and everyone would be on it. But its been around for 100 years and it is still only used as a laxative in a medical setting.
The people that may experience ‘higher mental energy’ are the people that are starting keto and have a keto coffee with MCT oil for the first time.
In that case, it is more likely the keto diet and addition of coffee that is causing the higher mental energy, not the MCT oil.
It is useful to keep in the cupboard as a laxative if you feel you need it. I found that 2 tablespoons does not do anything for me, but 4 a day for a week will smooth out any problems i might have.
Lastly… I add MCT oil to my coffee for 2 reasons…
1, because i want to add fat to my coffee first thing in the morning as MCT oil easy, I dont have to cut butter from the fridge, its quick and easy to pour.
2, I ont use coconut oil much and I want to have as wide of a spectrum in my diet as possible as I think thats healthy.
verdict - MCT oil good, useful, but not for the reasons a lot of keto people talk about.