Why We Eat Whatever Is In Front Of Us

We suck at portion control. When food is placed in front of us, we tend to follow mum's advice and clean our plates, even when it's more than we actually want. Here's why we do that, as well as a few tricks to keep yourself from overeating.

The occasional bout of overeating is inevitable, and it's not necessarily a bad thing. But when we do it too often, it not only increases the chance of gaining weight, it also just makes us feel gross for a couple hours. Science is still unravelling the mysteries of exactly why this is, but we do know a few reasons behind it and a few tricks to help keep it from happening.

The Psychology Behind Why We Suck at Portion Control

If you've ever felt the burn of eating an entire bag of chips in one sitting, then you know we aren't wired for portion control. Put some tasty food in front of a person, and chances are they will gobble it all down until the plate's empty. There's a science behind overeating in general as well, but we'll just take a look at why researchers think we're so bad a portion control in particular.

A number of experiments over the years have watched this happen. One experiment in 2005 used self-refilling soup bowls to look at visual cues in relation to portion control. Essentially, a tube was hooked up to the bottom of a bowl of soup. As people ate, the actual volume never decreased. The result? Participants with the auto-refilling bowl ate an astounding 73 per cent more than those who had normal bowls without even noticing.

Another study, done in 2006, looked at what happens when we're offered food from different-sized containers. For example, when participants were given a big scoop to grab their own M&Ms from a bowl, they filled up the whole scoop and ate it all. If it was a smaller scoop, they did the same. Essentially, the size of the scoop determined how much was "enough". This study also gave us the name unit bias: the tendency to finish off a given unit of an item when it's offered. In an interview with NPR, behaviour psychologist Matt Wallaert sums up unit bias like so:

Nobody eats one and a quarter apples, right? The unit is an apple. And so you eat an apple. And so you can apply that same sort of experimental logic to things like bags of chips. And you can actually make a bag of chips 20 per cent bigger, and 20 per cent smaller. And people still eat one bag of chips, and they eat until it's done.

Basically, we don't know when to put on the brakes with food. That's not just on the plate either; if food comes in a package that looks like a single serving, we'll treat it like one, even when it's not. As this article in the Wall Street Journal points out, bite-sized snacks are just as capable of making us overeat as an endless bowl of soup:

Certain types of eaters — people who are concerned about how they look or who aren't naturally good at controlling their eating — see bite-size pieces of food as "zero calories." In doing so, they tend to eat more than a regular-sized version of the food, says Pierre Chandon, a marketing professor who studies eating behaviour at Insead, an international business school based in France. "Twenty-five calories is not a serving, so we nibble without thinking we are eating," he says.

Essentially, we eat what's in front of us because we're not thinking about it, and there isn't any clear sign to stop eating. It doesn't necessarily have to do with our hunger, it's likely more about the environmental cues. It's not just unhealthy food either — we'll do this with everything from broccoli to chocolate cake. While the long-term health effects are different depending on what you eat, the short-term effects — that horrible feeling you get when you eat way too much — is pretty much the same no matter what you're eating.

How to Keep Your Portions In Check

Keeping your portions in check is a lot easier said than done. If you eat at a restaurant you're likely getting more food than you actually need, and cooking for yourself often yields the same results.

Since we know we're almost always going to eat what's in front of us, one step is to prepare the right amount of food in the first place. This is surprisingly hard, but as we've shown you before, you can measure portions with just your hands to make the prep a little easier. If you get the portion right in the first place, chances are that once you've eaten and clean your plate you won't be hungry.

Scaling back your portions on snacks is one of the toughest things to do. As we've pointed out before, the best thing you can do is eat normal-sized portions of healthier food. Say, a cup of blueberries and some almonds instead of a giant bowl of ice cream. Is this easy? No, not at all. It requires a complete change to your diet, but at least you still get to eat.

Part of the issue with portion control is also just simple packaging: a bag of chips, microwave meal or candy might look like a single portion because it's packaged in a single box. If you actually look at the details, you'll see that the serving size inside that box is more than one. The only thing you can really do here is pour out those chips or whatever else into a bowl instead of eating them directly from the box. At the very least, when you get to the bottom of the bowl, you'll have to get up and refill it if you want more.

The same idea even extends to plate sizes. When you use smaller plates, you're less likely to eat more or go back for seconds. Even the size of the fork has been shown to change how much we eat. It's not foolproof by any means, but it's one of the subtle ways to get your portions down.

More recent is the idea of "mindful eating". This seeks to tackle the idea that we go unconscious when we're eating head on. The thought is that if we actually think about what we're eating while we're doing it, we're more likely to pay attention to the cues to stop eating. Essentially, mindful eating is about slowing down and practising self control. Does it work? Arguments both pro and con are out there. It's no secret that slowing down eating gives you the opportunity to actually pay attention to your hunger, but it's surprisingly hard in practice.

It's worth noting that portion control isn't some magic diet trick. Sure, it's helpful for losing weight, and training yourself to recognise when you're full is good in the long run. But you'll still need all that other stuff like healthy eating and exercise. The fact is that since most of this happens without us realising it, controlling portions is a heck of a lot harder than it seems like it should be.

Pictures: thienzieyung/Flickr, Kritacher/Flickr, Crystal/Flickr


Comments

    An article in the Age today also suggests that education about eating and mindful eating strategies are not particularly helpful.

    http://www.theage.com.au/lifestyle/diet-and-fitness/diet-education-theory-cops-a-supersized-blow-20130417-2i0hi.html

      From that article:
      Participants placed in the ''education group'' were given a brochure about how external factors, such as mood, advertising and portion size, can contribute to overeating. Those placed in the ''mindfulness group'' were taught how to focus on internal sensations such as taste, hunger and satiety before they were offered the pasta.

      I would hardly consider either of those actions to be education. When you're properly educated in a skill, you don't just read a brochure about it, or listen to someone talk about "how to focus" on something. You practice it. And get assessed on how well you do it. If you fail, you practice it again until you get it right.

      So I guess the real result of the study is that minimal effort leads to no discernible results. No surprise there.

    Could it partly be because we have been psychologically conditioned by our parents forcing us to eat everything on our plate, even if we're no longer hungry, so as not to waste anything? Do it enough (for example, throughout your entire childhood), and it becomes second nature.

      This - as a child, how many times were you guilt-tripped into eating everything on the plate by being told "there are starving kids in Africa" or something similar?"

      Ha, yes - very true! I do use the "if you eat your dinner, you can have dessert" trick with my 3 y.o. son, but I don't expect him to finish his meal. It's more just to prevent him from taking 1 mouthful, then asking for ice-cream. He's actually quite good at eating only what he wants to and will skip dessert if he is full.

    To be honest, i would rather finish everything on my plate, then wasting the food, as long as you burn it off some exercise later. Anyone agree?

    The main time i over eat is at a restaurant, if i paid $30 for a meal, i'm going to eat the whole damn thing.

    The next main time is when eating pizza, i will eat that till i'm sick.

    With bags of chips, when at home i often take a handful out of the bag put them in a bowl and eat from the bowl instead of the bag that way you can actually tell how much you've eaten rather than putting your hand in the bag to find out its all gone, esp when watching TV when your doing mindless snacking.

    The easiest way to do portion control is buy a good set of scales and weigh everything. Just look on the pack to see the recommended serving size and weigh it out. You'd be surprised at the amounts. I get comments virtually every week saying how tiny my pot of cereal is (I eat breakfast at work). I tell everyone it's the recommended size of 50g even though it looks like half a handful.

      -

      Last edited 17/09/13 9:32 am

        The serving size is based on what a "typical healthy adult" should eat. You can eat more if you are more active than normal. It was a bit of a shock to start with, but it's amazing how quickly your body gets used to how much (or little) you eat.

          Not sure where you got your info about it being what a "typical, healthy adult" should eat, but it's incorrect.

          http://www.choice.com.au/consumer-action/food-labelling/better-food-labelling-campaign/percentage-daily-intake-guides-discredited.aspx

            Interesting to see such a discrepancy! To be honest, I don't eat a lot of packaged foods (I make my own muesli and eat 50g). Of those I do eat, I know my own personal serving size. For example take pasta. My own serving size is about 70g (dried) - regardless of what the packet says for each brand.
            I think the point is, if you know how much you should eat (be it from the box or a proper nutrition guide) and compare it to how much you would serve up yourself, the proper serving size will be a lot smaller.

        The serving size is supposed to be a reflection on the amount of food you should be eating in a sitting or serve, not the amount of food most people actually eating. Since our society is so unhealthy in general, using an average measure of what people do consume would be a monstrously unhealthy serving to follow. Giving people a guideline on the packaging that was unhealthy to follow would only cause more problems.

      except that 'serving sizes' on things aren't about what you should eat, they're about marketing. a high-sugar cereal will usually have a lower serving size to make it look like there's less sugar per serving, often confusing consumers into believing there's less sugar in a bowl of it. a cereal boasting high iron content will often have a large serving size for a similar reason.

        Or maybe a serving size of a high sugar cereal SHOULD be smaller than one that isn't high in sugar? Much in the same way you should only have a few squares of chocolate per day, but you can eat as many vegetables as you like.
        I do agree with you though about the marketing. If an unsuspecting person is just comparing sugar content per serve, and then just pouring out a bowl regardless of serving size, then they could certainly be eating more sugar than they think.

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