Not like my non-scientific experience is needed here, but in my experience this study is absolutely correct. Having done Atkins for almost three months now, I can say that I know that the week of my period and the few days before are a total wash - I never lose weight, even with exercise. But about a week and a half later my body starts into ketosis quite strongly and I lose 2-3 pounds all at once....very frustrating the first few months, but now I'm used to it and I no longer expect the scale to move every week

-Jinkster