I&#x27;ve never heard it stated in terms of mass, I&#x27;ve always heard it in terms of a human body having many more bacterial than human cells. But that is being revisited (probably the research you mention):<p><a href="http:&#x2F;&#x2F;www.nature.com&#x2F;news&#x2F;scientists-bust-myth-that-our-bodies-have-more-bacteria-than-human-cells-1.19136" rel="nofollow">http:&#x2F;&#x2F;www.nature.com&#x2F;news&#x2F;scientists-bust-myth-that-our-bod...</a><p>Turns out it is probably ~1:1.