> But before we throw out the low-carb approach to weight loss and load up on a bowl of linguini, let’s be clear: This study had some important limitations, leading some researchers to react more cautiously. It lacked a control for comparison, and while the baseline diet was designed to keep participants at about the same levels of energy burn they experienced outside of the study, the participants started to lose weight on that diet too. So they were already slimming down by the time they started their low-carb month.
Essentially the study took obese participants and placed them in a controlled environment, forcing a change in their real baseline diet, and decided to define the newly enforced diet as the baseline. Yet, apparently researchers failed to account for the fact that enforcing the baseline diet was already leading the subjects to lose weight, and thus decided to register the initial weight loss as the baseline.
So, in the end they compared the weight loss caused by the low carb diet with what researchers decided to consider the baseline result (the transition period to the new diet which was already causing weight loss in subjects). Then, as the weight loss observed during the low carb diet hadn't accelerated that much when compared with the weight loss observed during the diet transition period, they somehow concluded that low carb diet isn't that effective.