In general, people eat faster when they’re with family and longer when they’re with friends, says study author Helen Ruddock, Ph.D., a researcher in the psychology department at the University of Birmingham in England. Both effects can lead to overeating.
There may also be an evolutionary explanation for this trend: Hunter-gatherers developed the habit of matching their peers’ intake to make sure they got enough food when it was available, Ruddock explains.
The bottom line:
Simply being aware of the tendency can make you less vulnerable to it. Adds Sarah Maughan, a Precision Nutrition coach who splits her time between Toronto and LA: "Remind yourself why you're there—to have quality social time." Practice mindful eating and focus solely on conversation (not lingering leftovers) once you're full.