Insulin is used by your body for homeostasis.
Homeostasis - your body regulating itself i.e - temperature, water levels and blood glucose levels.
Insulin is released by your pancreas to lower blood glucose levels.
So if you eat white bread, it will turn into glucose (through various stages using enzymes) and then your body will have higher blood glucose levels.
Assuming you don’t exercise to use the glucose from the white bread for energy, insulin will be released to lower the glucose levels.
Not quite; insulin will still be released, since you can’t immediately burn of the energy from the bread to compensate for the rise in blood glucose.
If you eat a bowl of pure fibre, nothing will happen because it will just go straight through your system and your blood glucose levels will not be effected.
A typical example of insulin response is Diabetes (Type 1)
When someone is a type 1 diabetic, they don’t produce insulin (or not enough insulin) so they require insulin injections to lower the blood glucose levels.
Type I diabetics do not produce any insulin. Type II have the capacity to make insulin, but increadibly poor sensitivity.
So if they ate 5 mars bars, they glucose levels would be shockingly high and they could die if they did not inject insulin to bring it down.
That should be enough to help you with your insulin response question.
Glycemic index is fairly simple, High GI = higher sugar foods like cakes etc, so if you understand the above, you should understand it will result in a higher insulin response.
Low GI = lower sugar foods like rice, oatmeal, and this results in a longer sustained release of insulin. If any at all, because exercise could lower the blood glucose concentration anyway.
You can learn this in high school biology or through 15 minutes of google and its terrible you needed to come on here to find out to get yourself a job.
They should of asked you this shit on the spot in my opinion.
Oh thats just being picky <=P