A bell rings; a dog drools. That’s all it takes for a pooch to expect something to eat. It’s the oldest trick in the psychology book. Dumb dogs!

Are your friends making you fat DECOR

Oh, wait. We humans are just as conditioned to eat when we’re not hungry. Which might explain the staggering tally of calories you ingest some days but don’t especially remember. Scientists in the US, Canada, the UK and Europe have long been investigating common triggers that cause peer-induced overeating – and their findings suggest how we can control those urges.

Who doesn’t want to be just like her thinnest friend, with her extra-small shirts and 26-inch waist? The problem is, we tend to emulate her when she’s stuffing herself.

In one US study, an undercover researcher – a size 0 woman, either dressed normally or in a size 16 fat suit – ordered food in front of study participants. In all cases, they made similar orders to hers. And she had the most influence when she looked thin: When she ate more, so did they.

Other research shows that as your number of dining partners increases, so does your calorie intake. One study even found that eating with others can prompt you to consume nearly double the calories you would when alone.
And the heavier your friends are, the higher your chances are of becoming overweight.

How? “By ‘sharing behaviour’,” explains Nicholas Christakis, a Harvard University physician and sociologist who explores this occurrence in his book, Connected. “It’s either ‘Let’s go running’ or ‘Let’s share these muffins’.”

Avoid eating in big groups – Have everyone meet for a drink after eating dinner separately. “If you’re already full when you walk into a restaurant, it’s much easier to avoid overeating,” says Susan Roberts, author of The “I” Diet and professor of nutrition at Boston’s Tufts University.

Invite a cute guy for dinner – Women tend to eat less when they’re in the company of men, “even when it’s not a dating situation”, says Lauren Slayton, a nutritionist in New York City.

Clear the plates quickly –“Women like to talk, and as long as there’s food in front of you, you’ll keep eating,” says Lauren.

Take your time – Eating slowly means you eat less, says a study involving college women in the US and large plates of pasta. When instructed to eat quickly, they sucked in an average of 646 calories in nine minutes. When told to chew 15 to 20 times per bite, they consumed 579 calories in 29 minutes – and reported still feeling full an hour later.

It’s been said a million times but is still true: Watching TV can make you fat. A recent US study found that TV viewers who saw snack commercials were inspired to eat just about anything, not just the brand advertised.

Another US study in 2006 showed that when test subjects watched TV for half an hour, they ate 36 per cent more calories of pizza, or 71 percent more calories of macaroni and cheese, compared with people who listened to music for the same period.

Other research has linked listening to music with higher food intake. Staring at a computer can also be an overeating hazard as well, so Lauren advises against emailing during lunch at work.

It’s the distractions that cause study subjects to eat more than they would have if they’d had no distractions at all. Successful dieters, however, tend to watch far less television than the average adult’s four hours a day. For instance, the majority of people in the US’ National Weight Control Registry, a group of about 10,000 people who’ve lost at least 13.6kg and kept it off for at least a year, average fewer than 10 hours of TV a week.

Track your TV time – That way, you can actively try to cut down the time you spend glued to the screen. After all, people who watched half as much telly than they normally did for three weeks burned an extra 119 calories per day – almost as much as walking more than 1.6km, another study found.

As a rule, Lauren tells her clients to watch just one hour of TV a day – but it’s fine to spend hours while doing cardio exercises, like hitting the treadmill.

So-called “diet foods” can sabotage the best weight-loss intentions – presumably because people think they can indulge. And forget portion-control snack bags because they don’t work. A European study found that, given the option of two large bags of chips or nine snack-size bags, 59 percent of participants chose the smaller bags – but ate twice as much as those who went for the large bags.

Even the mention of salad on a menu can paradoxically trigger less healthy meal choices among people who usually have self-control. A US study presented people with one menu that offered a buttered baked potato (considered the healthiest choice), chicken nuggets or French fries. A second menu listed those items as well as a side salad. When the salad was on offer, nearly three times as many people ordered the fries.

What’s more, participants who generally made a point of watching their intake were most likely to switch their order from the potato to the fries. The researchers theorise that the option of eating healthy makes diners feel they’ve achieved a goal, so they reward themselves with the indulgent choice.

Get the dressing on the side – This makes you more conscious of how much dressing you’re eating. Olive oil, healthy fat though it is, still has 120 calories per tablespoon – that’s two slices of bread.

Start with soup – According to a US study, subjects who had a vegetable-based, non-dairy soup as an appetiser at lunchtime ate 20 percent fewer total calories than people who skipped the soup.

Plan your salad buffet strategy – Aim for a 3 to 1 ratio – three portions of the good stuff like dark greens and lean protein (shrimp, plain tuna, beans), and one portion of a “treat ingredient”, such as nuts, cheese, bacon, avocado, croutons or dried fruit.

“The sight, smell and talk of food trigger real metabolic signals of hunger, even when your stomach is full,” Susan notes. In fact, proximity to fast-food outlets is linked with weight gain and obesity, according to a vast US study of teenagers.

But appetite is also influenced by more subliminal aspects. In another US study, people who were exposed to posters touting an exercise programme ate 54 percent more calories than those exposed to posters without a workout theme. Participants wanted to eat after reading sporty words like “active”.

Also, restaurant settings with glaring light prompt people to eat faster, and those with soft candlelight encourage them to linger and eat longer.

Hide your food – If you live with people who insist on having junk food in the house, keep the snacks on a high shelf, advises Jennifer Warren of the Physicians Healthy Weight Center in New Hampshire. Or double-bag ice-cream in the freezer so you can’t see it when you open the door.

This story was first published in Her World magazine April 2013 issue.