Calculating the stored chemical energy of a molecule

Hello,

I would like to know how you would calculate the "stored chemical" energy of a molecule.

For example, a molecule of glucose would have stored energy measurable in Kcal that can be released as heat if burnerd or processed in the body.

I am confused by so many different energy calculations (potential, vdw, etc) and simply wish to be able to calculate the number of cals of stored energy a molcule posseses.

Thank you,

Regards,

Stephen