Another wrinkle that makes the calculations more challenging: many foods, starchy ones in particular, have more available carbohydrate when cooked than when raw. The cooking process causes actual chemical changes. Most “smart” scales take this into account—they will report a higher carb count for a cooked food than for the equivalent weight when raw.
And, of course, some foods actually gain water when cooked, complicating the equation still further.
Hey, if it were easy, anybody could do it. Diabetes doesn’t change only challenge the body; it challenges the mind, too.