Many of the negative health effects for shift workers are caused by the different timing mechanisms in the body that are affected by circadian rhythms being out

Many of the negative health effects for shift workers are caused by the different timing mechanisms in the body that are affected by circadian rhythms being out of sync. For example, some systems will adjust to being asleep in the day, where others (like the liver) have less flexibility. One might imagine that when we eat would also matter in this context, since bedsides light exposure, access to food is notable for an effect on the circadian system. Evolutionarily, humans would have done far less eating in the dark, and we tend to stay up after dark on the regular, but our digestive and regulatory systems may not be staying up with us.