"Maybe a little more detail could be given with your menu choices for example, on your 11 day trip you mentioned."
The Perpetuem and Ultragen are only part of what I use on a trip. Other items include: Breakfast: 1 Nectar Nugget peanut butter chocolate bar, 1.25 oz @ 176 cal; 2 oz granola @ 238 cal; 1 oz Nido @ 141 cal; 1 oz coconut creme @ 210 cal; .5 oz whey protein @ 48 cal. Lunch(throughout the day) 5 oz of Perpetuem @ 569 cal. I sip it on the go and don't stop for a lunch break. Dinner: 2 oz wild rice sticks @ 286 cal; 2 oz Annies White Cheddar Bunnies @ 281 cal; 2 oz Adzuki Bean chips @294 cal; 1 oz olive oil @ 250 cal; 2 oz Diamond Nut Thins @272 cal 2/oz. This adds up to 2762 calories in 19.75 oz and contains 47% carbs, 10% protein, and 42% fat. For extra hard days, I substitute 3 oz of Ultragen for the 2 oz of nut thins and end up with 20.75 oz supplying 2782 calories. I have other versions of this menu to avoid boredom, but this will give you an idea of where Perpetuem and Ultragen fit in. A bit more explanation: I have learned from experience and study that I use about 4200-4400 calories/day and burn carbs to fat at a ratio of ~30% carbs and ~70% fat. Therefore, I structure my carried food to contain enough carbs to burn not only the dietary fat, but also body fat that supplies the difference between the 2762 calories I carry and what I actually burn. The 1296 calories of carbs(47%) I carry works out to about 30% of 4200 calories burned. Anyway, this is how I go about it, and it has worked very well for me so far. Richard Nisley is an excellent source of information on this approach, as is the Arctic1000 website writeup on food for RJ, Roman Dial, and Jason Keck's traverse of the Brooks Range. I have found it to be spot on, and as long as you're willing to bulk up a bit before a long trip, you can cut down the amount of food carried considerably and use your own body fat. I hope this helps.
Post script. This approach will work only as long as you have excess body fat to burn, without eating into the fat protecting your organs. After that, you will have to increase the amount of food you carry or start metabolizing muscle tissue. I haven't pushed the limit so far, but I have a hunch I could stretch it out 3-4 more days beyond 11 and that would be about it in my case. YMMV of course.
The biggest problem I have to deal with is finding a wide enough variety of ingredients that give me the proper balance of carbs to fats, with adequate protein, that are also palatable over 10-11 days. Theoretically, I could just use glucose, whey protein, and olive oil, which would make it easy to get the proportions right, but I don't think I could get through even one day of that.