From a scientific method perspective, you're not really going to get an accurate calorie count. Reason being is that caloric values change in between raw ingredients and final product for mostly every food product sold in a processed form. (sorry, wife's a scientist so I had to note that in there).
That being said, you can either do a total raw caloric count by storing a "per unit" measure of calories with your products table, and deriving the caloric value based on the recipe.
EG if you have "white flour" with a value of 1,592 calories per pound (unit) and is priced at $.56 per pound, and you have a recipe that calls for 2.5# (units) of flour, you could say that is 3,980 calories and $1.40.
Just treat calories the same way you're treating price (calories-per-unit lookup, instead of price-per-unit lookup) and you should be fine.
Then a plain summary field will calculate your sum total calories for the recipe, and you can even go further and divide that to get a per-serving calorie value of the recipe.
I think the hardest part would just be to get that per-unit value entered into your products table, not sure how much data you have there.