I think maybe she is referring to Physiological Insulin Resistance (as opposed to diabetic insulin resistance). They are not the same thing. You can Google PIR for more details. It can happen on a very low carb diet, but is easily remedied. It happened to me 12 months ago when my base levels suddenly notched up noticeably without any change to routine, yet the actual rises from before meals to after meals dropped a tad, and stayed that way for a few weeks until I was advised of a remedy. Just a couple of days with extra carbs sorted it, then back to low carb again. It hasn't happened again.