Title: Core Inflation Rate: What Is It?
Headings: 
U.S. & World Economies Economic Terms
What Is the Core Inflation Rate?
How It's Calculated and Its Critical Role
What Is Core Inflation?
Why Food and Energy Prices Are Volatile
How the Fed Uses the Core Inflation Rate
How It's Calculated
Why the Core Rate Is Critical
Article Sources

Content: CPI Less Food and Energy, PCE Excluding Food and Energy
Why Food and Energy Prices Are Volatile
Food and energy prices are volatile because they are traded on the commodities market. Most food (like wheat, pork, and beef) and energy (oil, gas, and natural gas) are traded all day long. For example, commodities traders bid up oil prices if they suspect its supply will fall or demand will rise. They might think a war will dry up the supply of oil. They'll buy oil at today's price to sell at tomorrow's higher anticipated price. That is enough to drive up oil prices. If the war doesn't materialize, oil prices fall when they sell. Food and energy prices are dependent on rapidly-changing human emotions, not slow-moving supply and demand. Food prices rise along with gas prices because food is transported by interstate trucking. It consumes a lot of gas.