Having recently made changes to my own eating, which still includes carbs but at a much less extreme amount, I'm amazed at the differences. I don't have diabetes and the doctors say my blood sugar control is very good, but the energy differences I feel before and after eating high carb food is insane.
Diet soda, although technically not containing carbs, prompts a similar insulin response to drinking sugared soda- the result is a blood sugar drop and a loss of energy that makes me want to eat and do nothing; not the best for weight loss.
I would like to see more attention given to what insulin really does: prompt your body to store blood sugar as fat. No wonder filling our bodies with sugar and then using insulin to 'remove' it is a bad idea.