From what I understand, my daily caloric needs for a female of my size and activity level is 1,900 cal/day. Following the Zone, this would be about 570 calories/day of protein and fat (and 142 g. protein and 63 g. fat/day), and 760 calories from carbs (190 grams of carbs). This is excessive for the 11 blocks that the Zone recommends, but if I stay in the blocks, I don't think I'm getting enough calories. Does anyone have any input on this, as I am a bit baffled?

A recent article may be of interest to you, check out www.drsears.com and look at "Ask Dr. Sears". Scroll down to the topic of ATP.

Here is a link that will hopefully get you there: http://www.drsears.com/tabId/399/it...2/ATP.aspx

Jessica, this may help to clarify things for you. It's a quote from Barry Sears (pg. 104, The Anti-Inflammation Zone”) will help you to understand this better:

“One of the more difficult concepts to get across to athletes, coaches, dieticians, and physicians is the differences between burning calories and producing ATP from calories. ATP is the chemical that is required not only for muscle contraction, but also for virtually all of our metabolism. ATP is made on an as-needed basis from either glucose of fat. Your production of ATP is far greater from a calorie of fat than from a calorie of glucose. In the Anti-Inflammation Zone you are primarily burning fat for ATP production as opposed to glucose. This means you are also making all the ATP you need, even though fewer calories are being expended. This is why diabetics, world-class athletes, or just plain normal people require fat fewer calories on the Zone Diet than calculated from the usual metabolic equations. It is because they are producing more ATP from less calories.”