I'm happy to answer your question, but note that I am not a nutritionist. My knowledge is based on my experience and readings of other people's work.

That said, you should be calculating your caloric requirements that include calories lost from exercise. That means your caloric need includes your Resting Metabolic Rate (RMR) PLUS the calories consumed during activity. If you have a polar that estimates Own Cal, that is among one of the best ways to judge expenditure. There is also a multiplier you could use... based on your description of your activity, you could use 1.55 (that's your RMR times 1.55). Now, to lose weight, you cut the caloric requirement by no more than 500 calories. Cut out more calories and you just won't have the energy you need and you could throw your body into starvation mode.

There are two additional points to note:

1) You should not be worried about your total body weight per se, but rather your body fat percentage. A trainer should also be able to do this. Or, get some calipers and do the testing yourself. In weight loss, the goal is to lose the fat, not the muscle. By being consumed solely on your weight, you could inadvertenetly be losing muscle... not good.

2) Macronutirient percentages (% of carbs, protein, & fat) and nutrient timing for exercise recovery are extremely important for maintaining muscle, providing energy, and refueling the body. Of course, the macronutirent breakdown depends on the level and type of exercise you are doing. A rough basis for estimating macros is 20% protein, 20-30% fat and 50-60% carbs. If you are just building endurance you would eat more fats; higher intensity activity requires more carbs; protein stays roughly 1 gram per pound of bodyweight. Be sure to get carbs in before activity, replenish carbs and protein during activity, and get plenty of carbs and protein IMMEDIATELY after exercise.

Joe Friel has co-authored a book titled "The Paleo Diet for Athletes". I just started getting into it, but it seems to follow much of what I have been reading and practicing myself. It is much more restrictive than what I have been following due to the exclusions of foods causing blood acidosis, but I'm looking forward to learning more and giving it a try.