According to recent research by the BBC looking at the way we cook, lard is actually good for you and trendy oils can cause cancer.
Yes of course you remember when your Gran stuck in a whole block of lard to cook your crispy roasties and it was perfectly normal.
Then after those lard-swimming days of yesteryear plenty of healthy nutritionists decided that lard was bad and oils like olive, vegetable and rapeseed were good.
But now, it's all changed again and it looks like Gran was on the right track.
In possibly the most bewildering revelation yet doctors in the BBC Two show Trust Me I'm A Doctor, say we should forgo cooking with oils and fats and stick with the trusty block of opaque goo.
According to research completed on the documentary fats and oils can break down and change radically which means that heating them up can cause problems.
Dr Michael Mosley says: "The problem is that when heated fats and oils can break down and produce chemicals that can cause heart disease and cancer."
When asked about what oils are healthy for you many people simply assume that if it contains the words 'vegetable', 'seed' and 'sunflower' then they must be good for you.
During experiments testing the different types of oils, the scientists were looking for a chemical within the oils called aldehydes - which they found.