There are some terrific liquid fuels available these days that can supply all your nutritional needs for an Ironman day. Many contain the required amounts of electrolytes as well.
They are simple to use and can avoid the fights with sticky gels, hard to open and chew bars etc.
The Australian product I have had enormous success with so many age group athletes is ENDURA OPTIMIZER . We encourage athletes to use it on long ride days and has been very effective in hot, humid conditions. The Vanilla flavour is very easy to consume.
I understand HIGH 5 also do a super carb liquid fuel product that works equally as well.
The occassional bar, cookie or even sandwich to break things up inconjunction will work a treat.
If anyone is serious about looking for a viable alternative to their current formulas send me an email I would be happy to provide further details - firstname.lastname@example.org