Fearpanic

did that some time ago, it’s not particularly nice tastewise, but you can just chug one or two shots a day - that’s about 700kcal if you do 40ml per “serving” the YouTuber “DougDoug” did something similar for his diet. if you buy the cheapest oil (here it’s sunflower I think) you’ll get extremely many calories per unit of Money. in Germany that’s about 3000 kcal per 1€

A quick Google search says it’s not exempt, so take that as you will.