I have a BMR of 1,996.6 at the moment, and I try and eat a max of 500 calories less then my BMR is which is about 1,500 calories (k its really 1496.6 but 1,500 is close enough) but if I know I am working out I will eat up to my BMR because I know full well if I burn 500+ calories at a work out that I will in fact not have taken in my BMR but less (I also try not to go below 1,200 calories in a day mostly because over time eating taking in less then 1,200 calories can apparently affect ones metabolism and thus weight loss).
In general I burn 3,500 calories a week and am seeing a steady weight loss because of it and am eating upwards of 1,800 calories a day and am averaging 2 pounds a week loss.
To calculate your BMR you can do the following for females…
Weight in Pounds times 4.38 equals
Height in Inches times 4.57 equals
add Weight and Height Together
Age times 4.7 equals
Now take away age from Weight and Height
now add 655 to your result and that is your Basal Metabolic Rate (BMR) the measure of the energy your body uses in normal everyday functions.
275 pounds x 4.36 = 1,199
60 inches x 4.57 = 274.2
1,199 + 274.2 = 1,473.2
28 x 4.7 = 131.6
WEIGHT/HEIGHT – AGE
1473.2 – 131.6 = 1,341.6
There are many different sites online which can give you an idea of how many calories you use for various work outs such as fitday.com it might not be the best but it does offer some info which can be helpful in addition to seeing a dietitian and working out what is right for you to be able to louse weight.
Luck and take care