Thoughts on nutrition

I've been thinking (yes, I do that too - occassionally). I have always thought the metabolic requirements of ironman triathlon and the use of carbonhydrates are largely misunderstood, and after reading Jonas Colting's Den nakna hälsan I'm even more convinced.
The key to competing in ironman triathlons is learning to swim, bike and run as fast as possible without having to go into the red zone, i.e. burn mostly carbon hydrates as energy. Because if you go there, you'll end up walking pretty soon. So why do so many triathletes train to eat and drink carbs every 10-15 minutes? Quoting Colting here – did the paleolitic man ingest power gels every 15 minutes when he chased down prey for hours, or days? No, he was starving and running on reserves (fat and protein).
It is a myth that one needs to keep ingesting carbonhydrates in order to maintain an intense effort level. That is true only if you have adapted your body to consuming sugar all the time.
It is surely possible – and necessary – to do an entire race on glucose (blood sugar) and glycogene (carbs stored in muscles and liver) - if it is an olympic distance or shorter race. Not an ironman. The glycogene reserves are at tops 500 g, which is 2000 calories. It takes some 8 000 - 10 000 calories to do an ironman. Simple maths. Even I can do it. 
I have for years been training long sessions using mostly water. For a 5h brick, bike+run, I might eat one energy bar (40g carbs) split into pieces. Some people eat at least one bar an hour. And they would find it impossible at first to run on water. During races, I might have two bars during the bike (5h) and perhaps 40-50 grams of carbon hydrates consisting of a mix of bars and gels during the run.
I'm not a world champion but still, I do at least as good or better as friends with similar aerobic capacity who eat the "recommended" 60g carbs/hour. You just have to learn to burn fats.
During some phases of a long race an energy gel can be very useful in order to get a quick boost (did that in Zurich last summer). But once you have ingested one energy gel you will have to keep eating them every 20-30 minutes or so, because the quick boost will result in a glucose dip and eventually cause your blood sugar to drop even lower than it was before.
Also, a lot of the energy products out there on the market are merely junk. Glucose syrupe and citric acid. You can save a lot of money by just buying candy instead.
I prefer musli bars. For example Vitargos Energikakan or High 5:s energy bar containing fruit and fructose deliver more longlasting energy. (Not sponsored, just my opinion.)
Some say training on reserves is detrimental for your recovery, and eating a lot of carbs during a workout makes you ready for another workout quicker. True, you can probably fill your glycogene stores faster. But that is not the key factor limiting your training schedule. The main limiting factor is your hormones and the time it takes to repair the muscle damage a workout causes.