Its basically the response of your body (insulin) to high dose of sugar/carbs after a meal. As opposed to basal or 2nd phase which keeps working round the clock to keep your BG in normal limists.
In some cases, including my own, the level of carb means nothing or very little. The amount of carbs depends on your intolerance to the amount eaten. If I may. An example, to something like oats, higher than normal spike. Potatoes, very high, rice, moderate spike. And portion sizes also comes into it, on again depending on individual.
I have always called it , the first phase insulin response, and because I don't want more insulin, only just enough because of the trigger in the second phase which in my condition is called by my endocrinologist, an overshoot.
So any or very little carb does trigger a poor first phase then an overshoot.
This first phase of insulin, is combined with many other hormones, which are necessary for digestion of which the senses, brain and stimulus.
I do believe before diagnosis, I had very poor health, which included all the symptoms of T2, but unaware of my circumstances, that I was going hypo, my ever changing list of GP's, and even one endocrinologist, didn't have a clue. I know I had insulin resistance, hyperglycaemia, hyperinsulinimia, fatty organs, poor overall digestive issues. Then a list of minor symptoms which filled a foolscap sheet! Then because of the overshoot of insulin which is always, too much. I have episodes of hypoglycaemia.
T2s, who also have a second phase, have a automatic correction because the liver corrects the imbalance, which is glucogenisis, which is the same action as when your energy (glucose) levels drop. I don't have this!
Which is why my GP called me weird! And my endocrinologist confirmed.
For the last century or more, the emphasis has been on research, the finding out what all the hormones and the role they play when in imbalance, finding a treatment for the imbalance, relying on drugs to maintain, rather than cure. Recent research is on the after effects of either hyper or hypo whatever hormonal imbalance, of the condition. But the overriding problem of endocrine conditions is now food is so important to a person's health.
There are so many different conditions that have come to light, due to food, such as eating disorders, allergies, intolerance. I have had lactose intolerance since very young, I have become carb intolerant, which is not a recognised health disorder.
Diabetes especially T2 covers a wide range of types and conditions. And is still confused with T1!
The causes are even more wide ranging.
Because of my rare condition, I had to do the research and discover what and how my body works. Since diagnosis a decade ago, I have a layman's understanding of my condition and because of the parallels between T2 and RH. I can understand the necessity in health management, because of the role that carbs and sugars have if you do have a predisposition to an imbalance in the dysregulation of BG levels.
There has never been enough preventative research into how our modern diets effect a portion of those susceptible patients. Obesity and diabetes have a huge impact on the NHS. And on health.