Eating and Drinking
In a Nutshell
The uterus is a muscle, and like all muscles it needs fuel to work efficiently. If you are dehydrated or starved, you may have a longer, more dysfunctional labor.
Dig Deeper
Often hospitals restrict diet during labor citing that it is risky if you end up with a cesarean birth because you can aspirate (breathe in) stomach acid. This comes from research in the 1940s that linked eating to aspiration. Modern anesthesia for non-emergent cesarean births almost always uses a local spinal block instead of general anesthesia (awake and numb vs "asleep"), so the risks of aspiration have dropped drastically.