This also equates to 350 slices of pizza consumed for every second! The average range of sesame seeds on a McDonald's Big Mac bun is 178. The Big Mac is a well-liked sandwich at McDonald's that is made up of lettuce, cheese, pickles, "exclusive sauce," onions, two slices of beef and a slice of bread in the middle. How lots of seeds (on typical) are on a McDonald's Big Mac bun?