Contrary to the advice given by legions of nutritionists and diet guides, making a shopping list may actually increase a shopper's chance of selecting unhealthier food options. According to a study conducted at Duke University and published in the "Journal of Consumer Research," the mental effort that it takes to make a shopping list may actually lead to decreased impulse control.
• Conventional wisdom tells dieters to make shopping lists before going to the store to decrease their chance of making impulse buys of unhealthy foods and snacks.
• In the Duke study, college students were given tasks to simulate shopping either with or without a list. To simulate supermarket shopping, they were asked to choose from objects in front of them; to simulate making a list, they were asked to choose which items they wanted from memory.
• Researchers found that students operating from memory were more likely to make unhealthy choices. The researchers theorize that the brain cannot activate both working memory (to make a list) and impulse control at the same time.
• Another study, published in the same journal, found that exercising restraint in one area led to decreased impulse control in others. This suggests that people may be more vulnerable to spending more money or making worse shopping choices if they have already been exercising a lot of self-control recently.
• The authors of the Duke study suggest that shoppers still make lists, but double check them to remove any undesirable items that might have "snuck in."
• Quote: "If I am spending mental effort formulating my lists, then that is mental effort I do not have in terms of making sensible choices." - Lead Researcher Yuval Rottenstreich
• This study seems fatally flawed. Study subjects did not actually make a physical list, they were simply told to make a "mental" list. A physical list, written on paper, is much easier to adhere to than a mental list.
• I still recommend making a list before shopping for groceries. Put it on paper, however, and don't rely on memory alone.