fat loss and replacement of calories burned

That does happen and you end up putting on fat and losing muscle.  I would try to focus on proper caloric intake surrounding exercise, meaning right before hand, during and recovery, and cut the calories out of your normal meals that really aren't tied into your workouts.  So still maintain 200 cal per hour while working out and have the proper recovery drink/meal, but then 4 hours later when you have lunch, cut your calories there 

Also, note that most calorie-expenditure calculators tend to overestimate calories burned, some grossly so.  I have a Timex HRM, and even adjusting for my weight, it is way off in my opinion.  For example, for my 13k run this weekend, it said I burned around 1500 calories.  I don't think so!! 

 Might I suggest that you try just eating when you're hungry and stopping when you're full?  Our bodies are pretty smart, you know.

Hey Autumn,

I appreciate the need for structure. :-)

Everything I have read that says to cut 500 calories from your diet ALSO says to burn 500 calories in activity, for a total daily caloric defecit of 1,000 calories.  The idea is that 1 lb of fat contains around 3,500 calories , so after 7 days on this regimen you should lose 2 lbs.  Hence, the 2 lbs per week of sustainable weight loss addage.  It's not that 2 lbs is some magical amount of fat loss that the body can sustain.  It's that a 1000 calorie defecit, with about 500 coming from reduced calorie intake and 500 coming from increased calorie burns, seems to be sustainable in terms of a lifestyle change.

 The point here is not the cutting 500 calories from your diet, but the overall daily defecit of 1000 calories.  That's what allows for fat loss.  So, assuming that your "normal" meals are exactly matched to your baseline metabolic calorie burn for the day, which would produce zero defecit, and you burn 2000 calories in your workouts, you would want to "replace" 1000 calories of what you burned to end up with a total overall caloric defecit of 1000 calories that day.  Of course, you would want to spread out your "make up" calories between workouts.  Other than that, I'm not sure it has to be very complicated.

 Am I making sense?

Re-reading that last post, it doesn't even sound very clear to me!  Haha!  Here's an example of what I mean:

Say that the amount of calories you need to take in to maintain your weight (based on your activity level, excluding your workouts) is 2100 calories.  Say also that you have two workouts per day, a run that burns 500 calories and a ride that burns 1000. 

Calories in - calories out = caloric defecit

2100 (from meals) - 2100 (for baseline metabolic rate) - 1500 (from workouts) = -1500

So you'd have a 1500 calorie defecit.  Now, if you're shooting for a 1000 calorie defecit, that means you need to add back in 500 more calories to account for your workouts, for a total daily intake of 2600 calories.  Your day might look something like this:

Pre-run snack of 200 calories

Morning run, followed by breakfast of 400 calories

Lunch of 600 calories

Afternoon snack of 300 calories

Afternoon ride, taking in 200 calories while riding and 300 calories as a post-ride snack

 Dinner of 600 calories

 Of course, there are many other ways to get the calories in.  I'm just trying to give an example here of how you might add back in some calories burned in your workout to reach a total daily defecit of 1000 calories.

Autumn,

Any luck with your formula?

Also, I've been reading sports nutrition for endurance athletes (which you mentioned in an earlier post about balancing nutrition) and discovered the same thing you did about carbs...depending on the workout, I should be getting anywhere from 344 g carbs to 688 g carbs. Whoa...seems like alot. Are you working on incorporating more carbs as well?

I'm where you were in January with trying to figure out my nutrition!