Dining with someone who always goes for the unhealthy option makes you more likely to give in to temptation as well, a study has found.
Meanwhile a friend or partner who always turns down the chips and opts for a healthy salad can encourage you to follow suit.
Psychologists at the University of Birmingham monitored 100 women at a lunch buffet and found they were significantly influenced by the food choices of those around them.
When people around them helped themselves to the fattening array of cocktail sausages, pasties and crisps, while avoiding vegetables, the women tended to as well.
Again when someone tucked into carrot sticks, tomatoes and rice cakes, they also went for the healthy option and consumed 200 fewer calories than the other group.
"Our research suggests that eating with other people can affect our intentions to eat healthily," the Daily Mail quoted Dr Eric Robinson, who led the stud, as saying.
"We would advise people to be aware of what those around them are choosing to eat, and to make sure they stick to their intentions to eat a healthy diet," he added.
Studies have also shown that women eat more when a friend is indulging, but less in the presence of a desirable man.
Dr Suzanne Higgs, Reader in Psychobiology of Appetite at Birmingham said: "This research underlines the social nature of eating and how this influences our behaviour." (ANI)