Quick: who is the typical customer of McDonald's? If you answer "the poor," you'd be wrong.
See, contrary to conventional wisdom, the poor actually don't eat a lot at McDonald's, but people in the middle class do:
Leigh and colleague DaeHwan Kim analyzed 1994-96 data from the Continuing Survey of Food Intakes by Individuals and the accompanying Diet and Health Knowledge Survey. The data included responses from 5,000 Americans who were asked about restaurant dining habits, income, race, gender, age and education.
The researchers found that people visited fast-food restaurants more often as their household income increased — at least up to a point. Fast-food visits rose along with annual income up to $60,000; beyond that, visits started to drop back down, replaced by full-service, sit-down dining at slightly higher prices.
Based on the data, the researchers described the typical fast-food consumer as a lower-middle income head of household, who is budget-conscious and harried and likes the convenience and low price of fast food, compared with other restaurants. Poor people, by contrast, can't easily afford fast-food "value meals," and the poorest, who may rely on the FNS Supplemental Nutrition Assistance Program, or SNAP, certainly can't use food stamps at McDonald's.
Perhaps there is a stigma associated with poor people going to McDonald's? Maybe the inference is that "you are so poor, you can ONLY afford McDonald's"? And then when you get to the "rich", they would be reluctant to admit going to such a "low class" and "unhealthy" eatery (even though they love Big Macs just as much as we do).
So, really, the only people who would be truthful are Middle Class.