Don't try to compare the number of calories you eat when following the Zone diet to the BMR recommendations. Those recommendations are usually based on in individual who burns carbphydrate to produce ATP (Adenosine Triphosphate, the primary fuel used by cells to generate the biochemical reactions essential for life; the fuel for every muscle contraction that takes place). With the Zone diet the body burns fat to produce its ATP. More ATP is produced from one calorie of fat than from one calorie of carbohydrate. Following the Zone diet translates to fewer calories being consumed to produce more ATP as compared to following a typical higher carbohydrate diet.
With the Zone diet, you eat the amount of lean protein necessary to support your current muscle mass at your current physical activity level, and then compliment that with an appropriate amount low density carbohydrate and monounsaturated fat in order to maintain a low insulin level. This allows you to have excellent mental focus and clarity, to keep cellular inflammation to a minimum and to produce plenty of energy.
To apply all of this to your needs, I think you might be underestimating your activity level. CrossFit is primarily an anaerobic activity, comparable to strength training for Zone protein requirement calculations. Though you have not delved into the specifics of your CrossFit and half marathon training, I'd suggest you use Very Active, or, at the least Active, rather than Moderate, simply for the reasons that 3-4 days of CrossFit is akin to 3-4 strength training sessions weekly plus you are adding the distance running training. As you mentioned, Very Active, assuming 135lb LBM, gives you a daily protein recommendation of 122 g, which falls between 17 and 18 blocks daily. Try 17 blocks daily. Choose vegetables for most of you carbohydrate. Apply the 4 hour hunger test to further fine-tune to eliminate hunger.
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