Preliminary results from Chris Gardner’s follow-up to this study suggest insulin resistance may not be as big an influence on the success of LC/LF diets as prior studies have shown. Maybe I was wrong.
We aren’t given many details in the abstract or interviews, and there are still some good studies showing otherwise (eg, those by Cornier, Pittas, Ebbeling, and Gardner himself), although this one is bigger (n = 609) and longer (1 year). However, the range of weight change was huge, something like +20 lbs to -80 lbs, so the devil might be in the details… time will tell. Might be subtle yet important changes in body comp or other metabolic indicators.
If it turns out to be true, my best guess: they were all following Hunger-Free Diet(s)… which work regardless of whether low fat or low carb.