By Mike Pomranz
Updated July 25, 2016
Credit: © Bloomberg / Getty Images

We’ve all heard the advice: “Don’t go grocery shopping when you’re hungry.” The logic seems intuitive enough. When you’re hungry, you’re likely to buy more food more impulsively. And yet when it comes to grabbing lunch, often times we find ourselves waiting to eat until we’re absolutely starving. Unsurprisingly, recent research suggests that this habit could be just as bad as the old grocery store adage.

Researchers from the University of Pennsylvania and Carnegie Mellon University looked into how advance ordering might lead to healthier eating. Indeed, in three separate studies, the research team found that ordering lunch an hour or more in advance resulted in a lower calorie meal. “Our results show that ordering meals when you’re already hungry and ready to eat leads to an overall increase in the number of calories ordered, and suggest that by ordering meals in advance, the likelihood of making indulgent purchases is drastically reduced,” lead author Eric M. Van Epps was quoted as saying.

In the first study, which looked at over 1,000 orders that could be placed any time after 7am for an 11 am to 2 pm pickup time, researchers found that each hour between ordering and pickup equaled 38 fewer calories in the items ordered. A second study found that those who placed orders an average of 168 minutes before pickup time ordered food with 30 fewer calories than those whose orders were placed 42 minutes in advance. Finally, a study that looked at college students who either ordered lunch before class or after class at lunchtime found that the pre-class orders were 890 calories on average compared to the post-class orders that were a whopping 999 calories on average.

“These findings provide one more piece of evidence that decisions made in the heat of the moment are not as far-sighted as those made in advance,” said Carnegie Melon professor of economics and psychology George Loewenstein, who was also the study’s senior author. “For example, people who plan to practice safe sex often fail to do so when caught up in the act, and people who, in dispassionate moments, recognize the stupidity of road rage nevertheless regularly succumb to it. Unfortunately, pre-commitment strategies are more feasible when it comes to diet than to many other ‘hot’ behaviors.”

Whoa. Professor Loewenstein. Let’s slow it down here. I thought we were just ordering lunch.