I think these are the key findings (from the abstract): "...both human and mouse adipose tissues retain cellular transcriptional changes after appreciable weigh

I think these are the key findings (from the abstract): "...both human and mouse adipose tissues retain cellular transcriptional changes after appreciable weight loss. Furthermore, we find persistent obesity-induced alterations in the epigenome of mouse adipocytes that negatively affect their function and response to metabolic stimuli. Mice carrying this obesogenic memory show accelerated rebound weight gain, and the epigenetic memory can explain future transcriptional deregulation in adipocytes in response to further high-fat diet feeding." I.e. human and mouse fat cells epigenetically change in response to weight gain*, they don't change back in response to weight loss, and in the mouse case they demonstrated that the mice with the changes gained the weight back faster. I would (naively) expect this to also be true in humans, which would explain why rebound weight gain is incredibly common. I personally see this as significant because it's evidence that obese people and formerly obese people are directly going to have more trouble getting thin, at the level of cell biology, than people who were always thin. *The abstract implies this about human cells but doesn't explicitly say so. I presume it's a known fact about human fat cells.