n00bs training rides - dunwich dynamo

(apart from guaging when to eat - any tips on this?)

Eat little and often. Really sugary stuff (i.e. jelly babies) should be for emergency use only.

Something like flapjack, malt loaf, a banana or three, sandwiches, etc. Ideally something that can be eaten whilst on the move.

I carry 3 or 4 McVities Chocolate covered flapjack in a little tri-bag that sits behind the stem. At a cafe stop I'll have beans on toast or a bacon/sausage sandwich. Ginsters "meat and fat wrapped in plastic" (a.k.a. cornish pasty, steak slice, sausage rolls) work a treat too and I usually carry one for mid-ride snack in the rackpack.

If, any point, you feel hungry then you've not eaten enough early enough, eat and take it easy until your body starts to digest it all.