That messes with the notion that only the Atkins group lost lots of weight, although the most compliant of them did lose the most. It seems that the most compliant lost more than twice the previously reported amount on the Zone and nearly three times the previously reported amount on the Ornish diet. The LEARN diet was not included in the adherence analysis. The authors of the review concluded this (bolding is mine):
Regardless of assigned diet groups, 12-month weight change was greater in the most adherent compared to the least adherent tertiles. These results suggest that strategies to increase adherence may deserve more emphasis than the specific macronutrient composition of the weight loss diet itself in supporting successful weight loss.
Oh dear. That's interesting. I wonder why that follow up study isn't bounding around the interwebs? Probably because it's a predictable and boring finding. Nobody likes to cheer for the mainstream.
Let's have a closer look at the actual results from the original study.
Firstly, there is something important to realise from the get-go. Apart from the difference between Atkins and Zone Diet (which as mentioned above, was not really), the weight lost between groups was not statistically significant at 12 months. That means that given the group sizes, we can't be sure that the apparent difference in weights is not just chance.
There is also something weird going on with bodyfat levels. It's a bit of an elephant in the room, if you ask me. Have a look at this:
The readers of Fit to Blog are pretty smart and I'm sure you can see what's going on. In the last six months of the study, all groups except Ornish are regaining fat and increasing their BMI. The LEARN group regained the most bodyfat, with Atkins second.