Fast food joints lure you in and encourage you to eat way more junk than you need to fill your belly. Dave Shaw exposes the tricks behind their trade.

Big budgets and mass marketing schemes inject a sense of familiarity that we crave for comfort. People feast on fast food for the pleasant rush derived from the addictive combination of processed meat, refined grain, sugar, salt and industrialised oils. But why do we tend to eat so much?

Prof Brian Wansink, a nutritional scientist from the University of Illinois, and author of best-selling book Mindless Eating, has helped explain the environmental influences driving food consumption in this review.

These crafty tricks are well-known in the food biz, but consumers are confused.

Here's how they do it;


The 'see food diet'

Fast food outlets are everywhere - every suburb, malls, airports and most public places - tempting people to eat, even when they're not hungry. "Simply seeing a food can stimulate unplanned consumption," Prof Wansink says. Waiting in line to order gives you plenty of time to check out the menu, dream up your ideal meal, all the while being distracted by the flow of food streaming past on other customers' trays. Now instead of getting one or two items, there's temptation to purchase sides, shakes and desserts.

Variety and choice

The menu is bursting with diversity, offering something for everyone. This tricks the customer in to believing they're in control of what, and how much, they eat. But it's not that simple. "People can unknowingly overeat unfavourable foods as much as they do their favourites," consumer behaviour expert, Prof Wansink says. Increasing the variety can increase consumption. Meal deals are a perfect example of the way this is played out by fast food restaurants, with the addition of one or two items usually being enough to convince the consumer to buy.

Smells and sounds

How often has the smell of food stolen your attention? The fast food fragrance - and flavour - is unmistakable. It connects us with the burger, the fries, (the junk), and we can't recreate it at home. "Odor can influence food consumption through taste enhancement," says Prof Wansink. It might not be the direct driver for eating more, but it will certainly make you want to eat something. Sound can also influence the dining experience, with more down-tempo music having a calming effect - inviting you to draw out your meal and eat more.

You don't even need to get out of your car to grab a feast of fast food. Photo / Thinkstock
You don't even need to get out of your car to grab a feast of fast food. Photo / Thinkstock


Fast food restaurants have destroyed the barrier of "effort" by increasing the "ease, access, or convenience with which a food can be consumed," Prof Wansink explains. Not only is cooking redundant, the invention of drive-thru means you don't even even have to get out of your car. The junk is wrapped, boxed and 'finger lickin' good'. This is the genius of the chicken nugget - eating poultry no longer requires cutlery or a plate, you can chow down bite-size pieces in one hand, making it as convenient, waste free and car friendly as the hamburger.


Increasing packaging size

There's no doubt junk food packaging has increased in size over the past 30 years, and evidence suggests this can lead to an increase in consumption. Portion sizes influence the amount eaten from an early age, a phenomenon known as "cleaning your plate". But adults continue this trend by eating from buckets heaving with chicken. And "even if individuals do not clean their plates or finish the package, the larger size gives them liberty to consume beyond the point where they might have stopped with a smaller, but still unconstrained, supply," Prof Wansink says.

The size-contrast illusion

For some reason we tend to focus on the height not the width of packaging. It has been shown that considerably "more fluid is poured into short, wide glasses than into tall, narrow glasses that hold the same volume," Prof Wansink gives as an example. The same can be said about meal deals - notice how fast food places serve food in flatter boxes that cram in far more that you might think - enticing the customer to buy more.

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