Is there a way to estimate the nutritional calorific value of a chemical
If carvone ($\ce{C10H14O1}$) is digested by the body using oxygen to generate carbon dioxide and water, you can estimate the heat of this chemical reaction:

$$\ce{C10H14O1 + aO2 -&gt; xCO2 + yH2O}$$

After balancing the equation:

$$\ce{C10H14O1 + 13O2 -&gt; 10CO2 + 7H2O}$$

The required enthalpy can be know from the formation heats of each molecule multiplied by the found factors.



A quick estimation

I just did this exercise using computational chemistry (B3LYP/6-31G(d) in Gaussian09) and found the following energies (in kcal/mol):


carvone: -291456.0217
oxygen: -94322.73333
carbon dioxide: -118326.709
water: -47947.30569


The change in energy of the reaction is then:

$$\begin{multline}10\times (\pu{-118327kcal/mol})+7\times (\pu{-47947kcal/mol})\\-1\times (\pu{-291456kcal/mol})-13\times (\pu{-94323kcal/mol}) = \pu{-1137 kcal/mol}\end{multline}$$

this is $\pu{-1137 kcal/mol}$ (exothermic, as expected).

Since molecular weight of carvone is $\pu{150.2 g/mol}$, we can convert to $\mathrm{kcal/g}$, the negative value indicates it releases heat:

$$\frac{\pu{-1137 kcal/mol}}{\pu{150.2 g/mol}} = \pu{-7.6 kcal/g}$$