I just want to add a couple of points.

There are at least two effects of carbs. One is to immediately increase blood glucose then insulin and as BG rises over 100, glucose is stored in the fat cells so don't eat so much carbs at one time such that BG goes over 100. Second is to switch from burning glucose to ketones such that the fat cells liberate their triglycerides (TAG) to make more ketones. This is done after glucose has been depleted AND there is an absence of insulin. Here is where the Insulin Index becomes important over and above the Glycemic Index.

So the author is right when he says (to paraphrase) "this is not that and that is not this" BUT the LC community is generally right in their "group think". Eating "good carbs" helps people not gain weight but once the weight is gained.... a lack of good (and bad) carbs helps a lot of people lose weight.