Kinda depends:
If your on a pleasure trip, cherry pick the grocery store, and clean them out of the light stuff..then pick out some small-heavy stuff....(Cavir for example)
+1 on the smoked oysters, packed in oil, also +1 on "C Rat" canned dinner, 1/day= pretty civilised, and weight be damed (2-3 days)

If you'r going "lite, fast &long" different rules apply, ( hoofing 15- 35 miles a day, with a purpose).....recipie for that is: 1/2LB peanut butter 1/8 lb jerkey, 1/8 lb dog food ( my personal favoret is gravey tran), and about a 1/4 pound of dog biscits-to scoop up the peanut buter,per day,,,, (as memory serves, ymmv.These are old estimates ,and thats going rough & fast, not for a fun walk, and by the way, I'm a small guy and I don't eat much),

I've made it on no more than 1/2 lb of peanut butter & crackers in a pinch, wasn't that bad;, Peanut butter is your friend, if you've got it