What did work
Eating super clean allowed me to recover really well from my workouts, and to do more workouts in general. My sleep was great, I didn't feel tired throughout the day, and I felt more alert mentally. I definitely think this is the way we should eat, ideally, and I plan to continue to model my eating on the Paleo principles.
I did lean out quite noticeably during the first 2 weeks as well, which was a nice boost in confidence and motivation.
Removing grains, dairy, and legumes from my diet helped my digestion immensely, and I experience no heartburn or digestive issues, whereas when I reintroduced these things I was instantly hit hard by indigestion, heartburn, and poop problems (sorry).
What didn't work
Eating super-strict is very taxing, mentally. I seem to be an all-or-nothing kind of guy, and, even though I hate to admit it, I am still enticed by crappy foods. Once I cheat a little bit the flood gates are open, and it's hard for me to close them. With Thanksgiving this helped the wheels to fall off completely. As a result I'm starting to think that a strict adherence to any kind of diet is going to be ultimately self-defeating.
So what now?
I'm going back to what I know works for me: calorie counting and eating mostly Paleo foods, but with the occasional (weekly) cheat meal. I need the accountability that tracking my intake provides, as well as the data I can go back and analyze. My nutritional aims are to keep wheat/rice/gluten/vegetable oils/seed oils to an absolute minimum because I know for a fact that these things cause a lot of havoc in my system. I will also be keeping my dairy intake low, with grass-fed butter, heavy cream, and whey protein being the only things I use on a regular basis. I'm also not going to freak out if I'm out with friends or family and something delicious shows up. I will enjoy it in moderation, and not get neurotic about it.
I will keep intermittent fasting in the mix, since it helps me eat less without feeling deprived. I will limit my booze intake to wine and tequila, with beer being rare, and I will also limit my daily intake to fit within my caloric goals (2200-2500 calories/day). As I mentioned before, my gym is doing another Paleo challenge starting this month and going until February. I'm going to participate, but I'll be using the rules I've outlined here, along with the accountability provided by others working toward the same goal, to optimize my chances of success.
Even though this experiment didn't work out as planned, it did provide a lot of useful information as to where I am weakest, and what to do about minimizing occasional slip-ups. That's good enough for me. I'll weigh in sometime this week and let you know where I'm at.