From Easy Delivery Co. Unofficial Wiki
Energy is one of the two primary effects on your character.
The energy bar appears on the left hand side of the screen, and consists of vertical segments. You start with four segments, but by consuming energy-restoring items, you are able to gain energy up to a maximum total of six segments.
When you are losing energy, half of a segment will begin to flash, before disappearing as it is expended.
You can recover energy by drinking Energy Drinks, Coffee, or Tea.