I have never eaten either

marmite or porridge.

Am I missing out?

I am really surprised by porridge. It's such a fallback when somewhere with only weird breakfast options.

I wouldn't choose it for pleasure but I would for tolerability and health.

Porridge you can dive straight in, but you might want to ask her to have a poo and a wash before going in for the marmite. 

Is what I think penguin and the sandman were trying to say.

Outboard grease is a perfectly good substitute for Marmite.  

Porridge on the other hand - if you can make yourself a pot in the East Asian style - rice porridge in a chicken broth, with chicken or fish slices, finely sliced ginger, spring onion and coriander garnish and a teaspoon of garlic oil on top - true love indeed.