The problem with studies, especially around food and nutrition, is that so many have contradicted other studies from over the years that no one knows what to believe.
It suggests that people who think they can indulge in food and blow off exercise for just a few weeks and then get back into action may be wrong. For a month, 18 people agreed to restrict their movement and to eat a huge amount of food, primarily fast food, daily. Weight and fat body mass increased in both (duh!), and though many participants lost some of the weight afterward, they still had a "noticeable gain" in body mass after a year.
I can relate to the idea that I can take a little time off and then get back on the wagon. Glaring examples of this came when I moved after college, and other times in that era. I'd do fast food, or whatever, "for a little bit" while the boxes were in transit, or while the pans were still in boxes, and before I tried to get back to however I'd been, that state no longer existed.
The study emanates from Sweden; the source is co-author Dr. Torbjorn Lindstrom, an associate professor in the department of medical and health sciences within the faculty of health sciences at Linkoping University.