A post over at the Fat Cyclist (entitled "I Fear My Bathroom Scale") got me thinking.
I first started cycling seriously a few years ago, when 9 months of being a PM and not working out had added about 20 pounds on my frame. The weight came off fairly easily, but I was hungry a fair bit, and it took me quite a while to come up with a nutrition plan that worked, both when I'm training hard and when I'm not.
The basic problem is that if you are a recreational athlete, you need two different diet approaches. Both have the aim of keeping your blood sugar at a consistent level, but the way that you do that during (and after) exercise is very different from how you do it the rest of the time. You also need to realize that an approach that works for mostly sedentary people may be the wrong thing for you as an athlete, with Atkins being the prototypical example of this.
There are two good books that I know that can help a lot. The first is Chris Carmichael's "Food for Fitness". Chris' hypothesis is that you should match what you eat to the period of training that you're in. That conceptually makes a lot of sense if you're on a fairly serious training regimen, but it probably over the top for many recreational athletes. That doesn't mean that this book isn't valuable, however - it has a lot of great basic nutritional information and covers fairly well how your diet needs are different than those of the sedentary part of the population.
The second book is "The South Beach Diet". In general, most diet books aren't very useful, but there's a lot of good science - and clinical research - behind the South Beach approach. To sum up, each fewer processed foods, more natural foods, and you'll keep your blood sugar more constant, and therefore not be hungry all the time. I know several people who have lost good amounts of weight while not spending a lot of time hungry. There are some sacrifices here - I don't eat as much pasta as I used to, nor rice, and when I do, they're the whole-wheat varieties. Same with bread. But it's something that's sustainable.
So, for me, I'm "South Beach" on most days, trying to eat things that will give me sustained energy. That often means eating a little more fat that you would on low-fat diets, which is a good thing in my book. There are a bunch of "south beach" brand foods in the supermarket, but the ones I've tried have been pretty poor, so I'd suggest staying with the natural food.
I then modify on days when I work out. During workouts, my goal is to get enough glucose into my system on a consistent basis so I can burn fat efficiently. For me, this means a snack about an hour before (banana or clif bar, something like that), then Accelerade to drink now and then plus something else to munch on during stops (sometimes Clif bars, sometimes newtons). If I get it right, I'll have a nice constant stream of glucose so that I can get most of my energy from my fat stores. If I do this right, I don't get that "I've got to eat and eat and eat" feeling that Mr. Fat Cyclist (can I can you "Fat"?) speaks about in his post.
On the first day of RSVP, I rode about 6 hours on Accelerade, a couple of clif bars, some beef jerky (sodium), and a few other assorted nibbles. That's not a lot of food, which means the bulk of my energy came from my fat stores. That's good - not only does it help with weight loss, it means that I can have plenty of energy without trying to each a lot, which is bad - you can only expect to get a limited number of calories from eating without getting too much food in your stomach.
I should also probably note that you may need to back off a bit if you're in a sport for weight loss. The goal is to get your fat-burning metabolism working well and to use that for the bulk of your ride - that means you need to spend most of your time in a comfortable aerobic range. If you can find a good group ride that isn't too gonzo for your fitness level, you can stay comfortably aerobic on the flats and then push yourself (if you want) on the hills. If you push too hard, you won't establish the aerobic engine that you need. Carmichael talks about this in "The ultimate ride", also a good book.
Oh, and I use my scale, but mostly to weight myself before and after workouts to see how I'm doing on hydration.