We've seen it time & time again in various experimental models. Most recently in Antelope Ground Squirrels and Mice with disrupted master circadian clocks. In humans, we see mood disorders, impaired nutrient partitioning, increased cancer risks, et cetera, et cetera.
And now fruit flies:
Flies were exposed to normal light during the day, and either 0 lux (full darkness), 1 lux (3x moonlight), 10 lux (street lights), or 100 lux (bright city lights) at night. All conditions were ecologically & physiologically relevant.
Females exposed to artificial light at night laid significantly fewer eggs than those who weren't.
That's pretty much the absolute worst thing for survival as a species.
Number of females who successfully laid eggs and number of eggs per female was significantly reduced by exposure to artificial light at night:
OK, maybe that's not the worst thing, but this definitely is!
Artificial light at night, circadian arrhythmia, SKIPPING BREAKFAST. Eat whatever Hunger-Free Diet you want to, but don't do those things.