Personally, I find it very difficult to come close to replacing the calories I typically consume in a day in just two meals. Additionally, the amount I can consume in those two meals typically decreases over the course of the month. It seems like a similar, but perhaps "softer"/less unpleasant means of getting the same result.
I find the fast during Ramadan to be an excellent exercise of self discipline. I am also convinced there is are a number of health benefit to observing the fast.
While this study has interesting implications, I think the fast undertaken by Muslims during Ramadan deserves more study.