Of course, adding chia for fiber and eating low on the glycemic index will moderate this blood sugar rise. But the formula can be used for a thumbnail approximation of how many carbs to eat at a time if you are diabetic.
For example, Sue weighs 200 pounds, and starts eating when her blood glucose falls to 110. She must limit her carb intake to 20 carb grams if she wants to keep her post prandial glucose below 180. (20 times 3 = 60 points post prandial rise in blood sugar from 20 carbs)
If Sue's goal is to eat 100 grams of protein and carbs, then she must eat 5 times per day in order to keep her blood sugar under control.