When it comes to consuming calories with a person of the opposite sex, sharing meals sparks significantly more jealousy than meeting that same person for coffee.

"Our research suggests that sharing lunch involves more than the physical consumption of calories," conclude co-authors Kevin M. Kniffin, a postdoctoral researcher at Cornell University's Dyson School of Applied Economics, and Brian Wansink, the director of Cornell's Food and Brand Lab, in their new paper, "It's Not Just Lunch: Extra-Pair Commensality Can Trigger Sexual Jealousy," which appears in the peer-reviewed journal, PLoS ONE.

Research by Kniffin and Wansink measured the amount of jealousy reported by current romantic partners if one of them were contacted by an ex lover and subsequently engaged in several food- and drink-based activities.

"We consistently found that meals elicit more jealousy than face-to-face interactions that do not involve eating -- such as having coffee," Kniffin said. "These results are consistent for both men and women."

For couples who are attuned to relationship risks, this study suggests that men and women who "do lunch" run the risk of a jealous spouse or partner at home.

"It's key to remember that from your spouse's perspective, it's not 'just lunch.' While meals can strengthen social relationships, they can also destroy them," Wansink said.

Note: If no author is given, the source is cited instead.

• Gender Difference
• Relationships
• Nutrition Research
• Consumer Behavior
• Psychology

• Interpersonal relationship
• Platonic love
• Delusion
• Human bonding
• Love
• Anger