The second main use of the colon is to introduce a list. You need to take care; many people assume that a colon always precedes a list. This is not the case. Again it is important to remember that the clause that precedes the colon must make complete sense on its own.
Have a look at these examples:
The potion contained some exotic ingredients: snails’ eyes, bats’ tongues and garlic.
The magic potion contained sesame seeds, bran flakes and coleslaw.
In the first sentence, the clause preceding the colon has a subject and a predicate and makes complete sense on its own ‘The potion contained some exotic ingredients.’ In the second sentence a colon should not be used, as the clause that would precede it would not make sense alone ‘The magic potion contained’.
So, in your example…
My favourite foods include the following:
Marmite
lentil soup
chocolate muffins
Or…
The following are my favourite foods:
Marmite
lentil soup
chocolate muffins
But whatever you do, don’t take my word for it.
Oh, and I’ve quoted from one of the hundreds of grammar websites, all saying the same thing.