I had the same problem, I then started importing steak from a butcher in Spain who is well known in the road cycling circles. great stuff I must admit. I have a steak roll on low GI bread with some peanut butter souce before the race and then just put some steak slices in a Ziploc bag and nibble on them during the race. oh yes, almost forgot, I have a mate who lives in the America states of United and he sent me some energy gel/ carb loader stuff that is apparently very popular amongst pro cyclist, it is even rumored to have been used by a certain 7 time tdf winner. The only thing is you have to administer it through a "drip" type bag that feeds directly into your vein, I don’t really like needles so have only used it a few times but seems to work great. But on more humorous side: I was having the same issues, and was advised by a guy who does IM to eat early to avoid the bonk. I was also bonking around 40-45km in and would normally start my eating around then as well. I then started eating at about 25km in and kept having small amounts the entire ride. (use those mcnabs energy bars) Another thing I realized was that my training rides averaged 45km and would only throw in a longer ride once or twice a month. I then started including a 5+ hour ride once a week and felt a massive difference at marathons.
