Beef. It's what for dinner...before you run a half-marathon.

One of the Determinants of Demand is "a change in consumer tastes/preferences".  Advertisers and other advocacy groups try to promote their products in order to influence the buying decisions of consumers.

Here is an example from a Beef Industry lobbying group (from Morning Ag Clips):

The beef checkoff’s Northeast Beef Promotion Initiative in partnership with the South Dakota Beef Industry Council, the Pennsylvania Beef Council and the Kentucky Beef Council encouraged runners to “fuel up” with lean beef at the Rock ‘n’ Roll Philadelphia Half Marathon Health & Fitness Expo, Sept. 16-17.

Nearly 30,000 runners and their families toured the expo during the two-day event.  Visitors to the beef booth were challenged to test their beef knowledge through the ever-popular beef trivia spin wheel to win beef-related prizes. Attendees also learned the importance of fueling with high-quality protein through the checkoff’s Protein Challenge campaign. The checkoff’s Millennial-2-Millennial advocates and Team Beef members assisted checkoff by staffing the beef both.  After interacting with booth staff, an on-site event survey showed that 88 percent of attendees polled felt the positives of beef to outweigh the negatives.

- See more at: https://www.morningagclips.com/runners-fuel-up-with-beef/#sthash.Kb94esx8.dpuf

Below I created some slides to show students how this plays out on the Demand side of a Market.

Hope it helps!