Ordering in advance of dining out could translate into a slimmer waistline, a new study finds.

A new study by researchers from the University of Pennsylvania and Carnegie Mellon University finds that people choose higher-calorie meals when ordering immediately before eating, and lower-calorie meals when orders are placed an hour or more in advance.

Researchers conducted two field studies examining online lunch orders of 690 employees using an onsite corporate cafeteria, and a third study with 195 university students selecting among catered lunch options. Across all three studies, the researchers noted that meals with higher calorie content were ordered and consumed when there were shorter (or no) waiting periods between ordering and eating.

In the first study, the researchers found that for every hour of delay between when the order was placed and the food was ready (average delay of 105 minutes), there was a decrease of approximately 38 calories in the items ordered.  In the second study, average delay of 168 minutes resulted in 30 less calories ordered. The third study showed that students who placed orders in advance ordered significantly fewer calories (an average of 890 calories) compared to those who ordered at lunchtime (an average of 999 calories).

In all three studies, lower caloric totals were generally not confined to any specific population subsets. The first study was a secondary data analysis of over 1,000 orders that could be placed any time after 7 a.m. to be picked up between 11 a.m. and 2 p.m. The second study randomly assigned participants to place orders before 10 a.m. or after 11 a.m. The third study randomly assigned university students to order lunch before or after class, with lunches provided immediately after class, the researchers say.

“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,” says George Loewenstein, lead author of the study, which appears in the Journal of Marketing Research.