system
Given the following post, respond as if you're commenting on Reddit:
human
How and why do diet and lifestyle changes reverse insulin resistance?

I'm newly diagnosed with fairly advanced prediabetes, and I've been reading some papers on its reversal, but one thing I'm struggling to find is- how and why do diet and exercise improve insulin sensitivity mechanistically?
gpt
If a muscle cell is not doing any work and is already full of glucose/glycogen it begins to down regulate the number of insulin receptors on its surface. Exercise causes muscle cells to use their glucose, creating a need for more glucose to find its way into those cells.

If your blood sugar is regularly high, all of your non-lipid cells begin to down regulate their insulin receptors, as again they don’t need the energy and apparently sugars are abundant. Lipid cells take excess glucose and convert it to fat to be released when glucose levels are low. By eating well, your blood sugar levels drop, and non-lipid cells start to up-regulate insulin receptors to ensure they have the energy they need to function.