Ultras - An ultramarathon is any running event longer than a marathon (i.e. 26.2 miles). An ultrarun is any unusually difficult running event, regardless of distance (e.g. Pikes Peak Marathon).
You should always have enough immediate glucose available for direct use. After 45 minutes average you deplete all reserves and need more. You should avoid meat three days prior to long train, and load carbs with fruits and vegetables. During rides you can use gels (only for races, because expensive), as well as "turrones" (pure glucose with peanut and "ostia" --christ bread), raisins, dry plumps, and other variants. For the post workout you can also mix protein powder with liquid to gain muscle strength back again quickly.