I am 51 now, and on day two of a tour, my body has switched to "convert all food stores to glycogen" mode. I am sure that I am slaughtering terms here. but my metabolism is in some other mode. Food does not last too long in my system. My historical pattern has been to eat breakfast, tear down camp, and then start riding. I am often ready to eat again just as I am riding off.
This has been a problem ever since my late 30's, but it seems to be getting worse.
A typical breakfast, is usually oatmeal or grits (corn meal). And will be metabolized in 60 - 90 minutes. I did some experiments on a tour I did this past weekend. I added more protein to my diet. Instead of just oatmeal for breakfast, I used protein enriched oatmeal, with a protein drink (whey based), and beef jerky. This staved off depletion by an additional hour, but I would like to get more mileage out of a meal than that.
Does anyone else have this problem? What do you do about it?