In the “exchange diet*” for diabetics, they recommend not using gravies and sauces.
Most likely the reason for that is the uncertainty of what is in there; a gravy can contain from zero to two fat exchanges, and sauces like pesto can be about as fatty as butter, while other sauces may have completely varying amounts of sugars, carbs, and/or fats.
Ever have biscuits and gravy for breakfast, at a diner? There’s well over a cup of gravy served, and from the cook’s point of view the purpose is to use up the bacon fat left from cooking bacon. They don’t necessarily have to restrain themselves to the 1 Tbsp flour, 1 Tbsp fat, 1 cup liquid proportion.
*The exchange diet involves you having an allowance of so many bread exchanges, so many meat exchanges, so many fat, so many fruit, etc. There’s a list of what is one exchange for each kind of food–I think a banana is two fruit exchanges, for instance. You choose the total number of exchanges based on how many calories you burn with your lifestyle, and the set-up makes it easier to get all your nutrition without fussy calorie calculations.
So adding sauces during the day can add multiple fat exchanges the person isn’t aware of, and can put weight on, which for diabetics is inadvisable.
