I tried some Sports Drinks but they made me feel nauseus. Now I take note of cravings. If I start craving a Ham & Cheese sandwich then I have one at a petrol station. I think your body knows best. Milk-shakes seem to be popular even amongst cyclists who never drink them at other times.
My most common craving is Bitter-Shandy. Beer is a no-no for me on rides but Bitter-Shandy seems to be a real pick-me-up (I guess it's a sugar/carb rush). Especially last Saturday when I was dehydrating on a 271km ride around the New Forest.
The only home-made drink I use is adding some blackcurrent squash to water to make it a bit more palatable (warm plastic water doesn't hit the spot sometimes).
As for my 300km ride, I finished in plenty of time. I target 5.5Hrs/100km normally. That is usually enough in the rolling countryside around here. Allows for a few stops/repairs and keeps you well on time.
Denmead 300 took exactly 16 hours and you are allowed 20. If you can cycle 100 miles then you can tackle a 300km. It's more about controlling the boredom and negative thoughts than pedalling I find.
The beauty of Audax is that you have a control every 50km or so where you get to chat with others. You realise that everyone goes thru bad spells and that a snack, drink and 20 mins off the bike can usually get you over it. I did a 202mile solo ride last year and it was much, much harder than a similar distance on an Audax. When you ride solo all you have to occupy yourself with is thinking how much it all hurts and how comfy your bed was (when you left it at 5am, 13 hours previously).
It IS addictive though. 12 months ago I met a lunatic on a 200km Audax who cycled 45km to the start (in the dark, cold and rain) then cycled 45km back home when it was finished (in dark, cold and rain).
12 months on that's exactly what I did on Lymington 200 this weekend (except it was nice weather AT 5am and 10pm).
You start thinking, "It's only 60km to the start in Lymington, if I set off at 5am I'll be there for the 8am start"). Then YOU are the lunatic people are pointing at.
Mainly though I think it's about finding a pace you can deal with all day. Sometimes it's hard to bring your speed down from your natural 25mile pace to a more leisurely one. I find that reducing it by just 1mph-2mph means I can keep pedalling all day instead of burning out after 5-6 hours. It becomes a matter of dealing with aches and pains (contact points, shoulders, neck) rather than fitness
As for foods that keep me going, remember that calories are your friend. On a 100 mile ride it's unlikely you will eat more than you will burn up. Eat what you fancy but MOST IMPORTANTLY, eat what you fancy before you get hungry. If you wait until you a really hungry then you are probably about 20 minutes away from trying to find gears below 1st.
Over the last 2 years my metabolism has changed (I was told it would) such that I can last much longer without needing to eat desperately (you start burning fat easier, which lasts days, and becoming less dependent on Blood Sugars, which last about 3 hours). Until this happens though you walk a fine line of depleting blood sugars. I highly recommend a small snack (energy bar, slice of Malt-Loaf) every 30-60 mins after the first 2 hours cycling.
if your mind or conversation turns to food IT'S AN EARLY WARNING from your brain, take heed, eat.
You are never quite as in touch with your metabolism as when you cycle beyond 100 miles. You learn that you have never REALLY been hungry before. Hungry is actually when you are in 1st gear on the flat, wishing you had stopped to eat an hour ago when your brain started flashing you images of a Ploughman's Lunch.
It's great when you get it right though
Good luck. .
