This is an interesting study – customers of McDonald’s and Subway were interviewed on their way out of the respective restaurants and asked how many calories they thought they had consumed.  Those data were then compared with how many they actually consumed.

The results of the Cornell University and University of Illinois study as published in USA Today are:

  • Customers at McDonald’s consumed about 710 calories and estimated that they had eaten about 670 calories each.
  • Those at Subway each ate about 560 calories but estimated only 335.

The customers at McDonald’s ate a lot of calories and knew they’d eaten a lot,” says Wansink, director of Cornell’s Food and Brand Lab. “But those at Subway experienced the ‘halo effect,’ which allowed them to think they were eating better than they were.”