Emily Dhurandhar, an obesity researcher at the University of Alabama at Birmingham, said retailers carefully manipulate pricing as well. "It's well known that higher prices reduce consumption. Marketers know that even strategic, short-term sales promotions can lead to long-term increases in consumption of a particular food," she said.
Cornell University studies also show that consumers who pay with plastic tend to throw caution to the wind. When they use credit and debit cards versus cash, they buy a larger proportion of food items rated as impulsive and unhealthy.
"Cash helps you feel the pain of spending and anticipate the regret from impulsive consumption," said Manoj Thomas, the lead author on the Cornell studies and director of the University's business simulation laboratory. "That alone seems to help hold back from consumption."
And, although impulse marketing is something that's used right under our noses, Cohen said she thinks we should consider treating it as a hidden risk factor for diet-related chronic diseases, like carcinogens in water, because it affects our food choices in ways that are automatic and out of our conscious control. They could well be contributing to the obesity epidemic that has left more than two thirds of Americans overweight or obese.
"We often talk about personal responsibility but we need to stop putting all the onus on individuals who are naturally influenced by their environment and born to overeat when there is too much food available," she said. "It becomes a barrier to good health when we undermine people by asking them to say no at every step."