The study was not set up to answer why the males fathered fewer pups or why the females died earlier. "The problem may be in the cardiovascular system, muscular system, reproductive system," Ruff says. "They use all of their systems to successfully compete." Thus, it's difficult to know whether these things could happen in other animals, including humans, that consume equivalent amounts of added sugar. Instead, the study offers a holistic view that Potts believes helps researchers detect small effects that would be difficult to find otherwise. Potts thinks there haven't been other papers on the effects of moderate sugar consumption in mice not because other scientists haven't tried such experiments, but because they then didn't find any interesting differences.