Dunwich Dynamo 2008

the key to doing the DD is not going too fast at the start and depleting the glycogen stored in your muscles too quickly and to start eating small amounts before you get hungry and before you are having to metabolise carbs into energy.
the worst thing you can do is to try and keep up with those who are faster than you. find your own pace where it's easy to hold a conversation without compromising your breathing. if you can find people of a similar speed to ride with it's even better. if you can draught each other properly and hold a wheel you will get there with less effort.

Not done the Dun Run (yet...) but this sounds about right. I think it's before you start metabolising fat into energy, though?

I suspect if you eat too much in one go at the halfway point or when you get to Dunwich it'll make you very sleepy - you know that feeling when you've had a big meal in the evening and you just want to doze? Not so fun when you're exerting yourself. It's probably better to keep topping up the carbs en route rather than ingesting a huge load of them in one go.