Livre d'Or

Possible, but technically tricky. You can get a reasonable ballpark figure by making a calculation which takes into account your weight, height and body fat percentage (all of which are fairly easy to measure), rather than just assuming you're an average woman, and also recording the amount of exercise that you personally do. To get a true, precise figure for your personal calorie requirement, you'd want to do some kind of measurement of respiratory quotient (which is basically to do with how efficiently you convert food calories into energy your body can use), and get a long term measure of how many calories your specific body is actually using via the doubly labelled water technique. People argue about how accurate the DLW technique really is, but it's more individualized than just going off population-based charts of BMI and body fat percentage.