I don't know about anyone else but one of my biggest fitness/eating issues is motivation--mostly maintaining it. Eating I'm still working on but I have been using something over the last year that has helped me with my fitness motivation.
I have been following the Eowyn Challenge. Last year I finished my trek from Hobbiton to Rivendell and very soon I will finish my trek from Rivendell to Lothlorien--I'm on mile 400 right now. Very soon I'll begin my trek from Lothlorien to Rauros which is 389 miles. I basically count a mile as 20 minutes of moderate to hard exercise since I don't really run(I tried it; it didn't take).
The Eowyn Challenge site is really fascinating; I cannot believe how much effort went into figuring it all out. It's really inspiring. Of course, if Lord of the Rings isn't your thing, you could always figure out mileage to a favorite destination or a dream trip around the world.
I use Tickerfactory to chart my progress and it really feels fantastic when I make it to one of my destinations :)
If anyone has any tricks that get them to stick to an eating plan, please let me know because I could use all the help I can get in that department.