As the article says, that was just a hypothesis. There's no mention of tracking insulin levels, only blood sugar. And what's more, type diabetes is described in the article as resistance to insulin.
I can think of at least one further hypothesis, which is that cutting out indigestible sugars, per Lustig, frees up the liver from the task of metabolizing fructose/sucrose etc., to respond correctly to insulin, allowing blood sugar to be regulated.
I can think of at least one further hypothesis, which is that cutting out indigestible sugars, per Lustig, frees up the liver from the task of metabolizing fructose/sucrose etc., to respond correctly to insulin, allowing blood sugar to be regulated.