How fast food reveals secrets of the economy

• Fast food consumption can be used as an index to measure consumer behaviour and market changes.
• The Pizza Principle, first noticed in New York City in the 80s, revealed that the cost of a subway ride and a slice of pizza remained the same for two decades.
• How much a Big Mac from Mcdonalds (or a similar offering from KFC) costs around the world can measure how the same product costs in different countries. If the product price is the same, the countries have a Purchasing Power Parity (PPP).

Financial experts and economists use popular food items like the Mars chocolate bars, popcorn, and baked beans as an index to measure the cost of living and to determine the health of the economy.

The Odeon Popcorn index(2009), for instance, showed that higher sales of popcorn, a cheap snack consumed by families, correlated with the economic recovery in the United Kingdom after the financial crisis of 2008.