I found a couple of interesting studies that look at the effect of a compressed eating window. This first study shows that circadian rhythms were important for determing the effects of food intake. Mice fed a high-fat diet during the 12-hour dark period (mice are obviously nocturnal) gained less weight than mice fed a high-fat diet during the 12-hour light period. This is similar to what you see in studies on shift workers.
The second study takes a different angle. The researchers again fed rats a high-fat diet. The control group had access to calories over 24 hours. The treatment group had a condensed feeding window of 8 hours. The result: no weight gain for the mice with the condensed eating window! This happened even though calorie intake was exactly the same in both groups.
So as far as I can tell from these two separate studies, even given a high-fat diet, shortening the feeding window from 12 to 8 hours will prevent obesity in mice.