I may not know much about mice, but I do know how they are different from humans. Being that they are the scratchy feet that run across the ceiling and floor boards at night tells me that they can work well under any conditions of light. This article suggests a correlation with the levels of light mice are given and weight gain. By being exposed to more light, the mice are said to have "gained more fat than the mice that lived in standard light conditions", being dimmed light, and dark conditions.
The article's reasoning for the weight gain, described that the mice were eating during their normal resting periods under conditions of exposed light. After the mice were put back on restricted food times, or when they normally ate, researchers didn't see the weight gain. Well, no way! Common sense sometimes makes all the difference! If mice are going to be exposed or able to see their food for a longer period of time, chances are they will eat for a longer period of time and, therefore, gain more weight. Now, the study would like to further research how this affects humans? Maybe the researchers should find more probable experiments and explanations first.