I've been at this for quite some time, and I've pretty much got my food thing dialed in for the way I hike. Most all of my trips are just 1-3 nights, so it's pretty easy to bulk back up when I get off the trail if I miscalculated. For example, on my recent month in Yellowstone, I did 7 trips in 25 days, from 1-3 nights each (14 nights total). I planned 2-3 zero days between hikes, where I could hit the salad bar and pig out on steak and pizza before I went out again. I'd make a pretty crappy thru hiker...
So I plan a breakfast, a lunch, and a dinner for each day I'm out. In addition, I usually carry 9-10 oz. of extra stuff for a 2-night outing, which I'll eat if I'm not into the food I brought, if I feel like a snack between meals, or if I decide to not stop for 1/2 hour to enjoy my sausage/cheese/bagel lunch. So I tend to carry 2 Kind bars, 3 oz. of nuts (1 oz. per pack), an oz. of Goldfish crackers, and then one ProBar (meal) in case the weather forces me into the tent and I don't feel like firing up the stove for dinner.
Most of the time I'll not eat the backup ProBar, and I'll also carry out 1/3 of the other stuff, or give away any extra Kind bars to wistful hikers I see on the way back to the TH. I also try to take my last sip of water when the truck comes into view, so that my pack weighs just 15-17# when I get there (then I think I'm quite cool).