Why eating with other people makes us fat

Studies suggest we eat more in the company of an overweight person, a man, a

spouse, family members, friends Why is this, and is there anything we can do

to control it?

Eating with other people is fattening. This has been demonstrated by umpteen

scientists who have our collective waistlines at heart. Take the fat suit

study (as it is informally known), just published in the latest issue of the

journal Appetite. A team of psychologists, led by Mitsuru Shimizu at Southern

Illinois University, found that people ate 31.6% more pasta and 43.5% less

salad when in the company of an overweight person, irrespective of how healthy

the overweight person s food servings were.

The experiment was following up on a hypothesis, explains Shimizu, that the

goal to eat healthily is deactivated by eating with someone who is overweight .

Probably, he continues, we have an unconscious goal to eat healthily,

because we are supposed to, but when eating with an overweight companion, maybe

that goal is less activated or deactivated.

This raises many questions not least, why in heavens did they hire an actor

and a fat suit instead of using a real overweight person? But, most pressingly,

what is the take-home lesson from these findings? It is, says Shimizu, a case

of forewarned is forearmed. These things are happening unconsciously, so if we

know that there is an influence from an overweight person, then maybe we can

avoid such an effect.

Companions = calories

When we eat with other people, we consume on average 44% more food than we do

when dining alone. In 1989, American psychologist John de Castro looked into

how eating in different-sized groups would affect food intake. In a later

review paper, he broke it down: Meals eaten with one other person present were

33% larger than meals eaten alone, whereas 47%, 58%, 69%, 70%, 72%, and 96%

increases were associated with two, three, four, five, six, and seven or more

people present, respectively. It was thought that this had something to do

with the fact that mealtimes are prolonged when eating in company. However, in

2010 a team at the University of Adelaide spied on lone diners at a fast-food

restaurant and observed that people whose meals took longer because they were

reading did not eat significantly more than anyone else, so there is more to it

than time spent at the table. Animals eat more in company, too. From rats to

chickens to puppies, if you feed them until they re full, then present them

with another of their species eating, they will start eating all over again.

Different strokes for different folks

A later study by de Castro discovered that who we eat with also affects

indulgence levels. Women ate 13% more when dining with a man (men s intake wasn

t affected by the gender of their companion). And meals with spouses, family

or friends are 22%, 23% and 14% larger, respectively, than meals eaten with

other people. We eat more when we re in relaxed company, which figures. De

Castro also found that we eat faster with our families and slower with friends.

The copycat effect

It is so hard not to be affected by what others choose to eat. When ordering in

restaurants, we may consciously try to order something that no one else has,

both in the name of variety and as part of a psychological phenomenon known as

the need for uniqueness . Unconsciously, however, we re giant copycats. Facial

expressions of others can affect food choice, as demonstrated in a French paper

published in Appetite in 2009. When subjects were shown an image of someone

exhibiting disgust while eating a food liked by the subjects, their desire to

eat it decreased. And when they were shown an image of someone enjoying a food

they disliked, their desire to eat it increased. Another experiment published

in the Journal of Consumer Research found that, when presented with two types

of crackers, people will be drawn to the same ones as a colleague they re

talking to.

Finally, when offered palatable snacks in polite company, we tend to take our

lead from others. Researchers at the University of Toronto deprived

participants of food for 24 hours before presenting them with nibbles in a

social setting. Despite being hungry like the wolf, if their companion ate very

little, the subjects restrained themselves. But gosh, it s annoying when that

happens. You want shovel in handfuls of crisps and then all the salt off your

fingers so much that you can t concentrate on the conversation. Or perhaps that

s just me. Do you notice your food choices being swayed by the company you

keep?