Mike notes the correct general guideline for subtracting fiber. For a single serving of food with more than 5 grams fiber, subtract HALF the fiber. That’s to account for the soluble vs. insoluble. Some foods, such as cereals, list both soluble and insoluble, but most labels do not give that breakdown.
It’s really only helpful if you eat a food with lots of fiber (like the 15 grams in your bread). Otherwise, you only get to subtract 2 or 3 grams, which doesn’t make a big difference in total units injected, even with a low insulin to carb ratio.
But, eating plenty of fiber is a great thing. It can keep blood sugar from spiking rapidly (it won’t necessarily decrease the peak, but it is likely to give you a smoother increase and decrease over a longer stretch, which allows any insulin your body produces or any that you take to better “match” the blood sugar. It can help you feel more satisfied with your meals.
PS: Forget the rice, Janet. Have you tried barley? High in fiber for a whole grain.