Rachel Feltman took a look at the amount of water logged in common food items:

• Each egg requires 53 gallons of water to produce. This includes the cost of water-intensive grain feed and drinking water.
• A classic Hershey bar requires 317 gallons of water to produce.
• A typical pizza slice costs 42 gallons of water. That includes the water for the dough, the cheese and the sauce. Mozzarella in particular is water heavy.
• However water use varies by region. A French pizza slice only costs requires 21 gallons of water.

Read more about the water embedded in every day food items here.

Source: Quartz