Two sources of information from the man Chrissie Wellington and Haile Gebrselassie turn to for nutrition advice, Asker Jeukendrup. There is a lot of useful information in these, but I would wager that a large percentage of folks would do well with just the two following points:
- You can get down 90grams of CHO per hour, but 30 of that needs to fructose and the other 60 glucose or maltodextrin. The trick is that the two sources use different pathways out of the gut. 4 calories/gram of glucose + 3 calories per gram for fructose means 33o calories per hour. Very important when Asker points out that they found a liner relationship between calories consumed (and kept down) and performance.
- You can train your gut to uptake more calories per hour. (I can get 400/hour with maltodextrin + fructose in a homemade gel.)
So many ultra-running folks I know use nuts, dates and almonds for fuel, I would be curious to see where Asker’s advice stands when mixing in these fatty foods.