I realise you hear this from me about once a week, but it's a bit of a nutty week for me.
I'm finishing up the last assignments for the semester, and one of them dealt with environmental influences on eating volume. In other words - when faced with this:
How much hamburger would a hamburger-eater eat?
It's a fascinating subject. I discovered a science article by Professor Brian Wansink, which informed me that I'm being manipulated to eat more (or less) by cues from my environment, whether I believe I am susceptible or not. It is true even if I am aware of the tricky things that affect how much I stuff into my gob. Nobody is immune.
Prof Wansink categorises these irresistible forces as part of the eating environment or food environment.
The Eating Environment refers to things that aren't actually food - the eating atmosphere, lighting, music, the social situation and how much effort is involved in getting your gob around a mars bar. Eating environment influences can be summarised as atmospherics, effort, others and distractions:
Atmosphere: There is a reason why fancy restaurants are dimly lit and play carefully selected music at the right volume. The restaurant aims to ease the stress out of your normally uptight eating habits, and wants you to linger. Relaxed lingerers eat more. They eat dessert, and have more drinks. In contrast, a venue that makes money through the 'revolving door' of customer turnover, will be bright and probably full of screaming kiddies. If the atmosphere is disagreeable enough, you may speed eat, inadvertently overeating in the process.
Effort: What is the difference between walking two blocks in the rain for a Magnum and getting one from your own freezer, twenty metres from the couch? Effort. People are very lazy. You will eat more of something if it is right in front of you. Put it on the other side of the room and you will eat less. Put the lid on the lolly jar and consumption drops again. You will eat fewer nuts if you have to shell them yourself and more with a fork than with chopsticks. The effort effect can be used to our advantage, and a good example is small packets. you may eat an entire bowl of popcorn, but if you finish a single serve packet of popcorn, the act of having to open a new packet may be enough of a deterrent to call it good at one.
Others: You eat more when in sociable company and the more people present, the more each eats. What I found most interesting is that the larger the group, the more people tended to eat similar amounts. This 'copy cat' effect was strongest in the obese.
Distraction: A distraction is anything that removes our attention from what we are eating. Professor Wansink talks about TV. As a distraction, TV can act as a cue to start eating, extend eating or stop eating. A person that is cued to stop eating when their program ends will eat more if there is an extended viewing, even if they are full. People are worse at estimating how much they ate if they were eating while distracted.
The Food Environment relates to the item about to be scarfed. How it looks, serving size, presentation and how much of it is available. Wansink refers to the 'five S's': Salience, Structure, Size, Stockpiling and Shape.
Salience: Do you remember the 'see food diet'? If I see it, I eat it? That is salience. If you can see it, or smell it, you are more likely to eat it. This extends even to such things as using a clear or opaque wrapping for your homemade muesli bars.
Structure and perceived variety: This is the buffet principle. When presented with a stunning array of delicious stuff, we want to try all the things. Have you noticed how buffets mix things up? Instead of putting all the sandwiches together, they spread them around, which makes the gullible human brain think there is more variety. If things are grouped and organised, people eat less. Silly, silly brain.
Size: Finally we can answer our burger-eater question. More burger = more burger eaten. The more food in front of you, the more you will eat. But, it is not quite that straight forward. People will eat more of the same amount of food from a half-filled large container than a mostly-full medium sized container. Interestingly, the effect extends beyond food - to things like washing powder. The larger packet, the more heaped our scoop.
Stockpiling: Having a stash of something, perhaps because you are bulkbuying on special, can make you eat more of that item, probably because you have thirty cans of baked beans in your face every time the cupboard is opened (more salient).
Serving dishes: Basically, the wider the plate, the smaller your food looks on it and therefore the more of it you eat. Taller, thinner plates (and glasses) encourage you to eat (or drink) less. Food in a larger plate is consistently estimated as having a lower calorie content than the same amount in a smaller plate - people genuinely think there is less there. If I have cereal, or icecream, I put it in a teacup. Automatic portion control, but it looks like so much all squished into that cup and melting off the edge.
A feature that might get ya from both the eating and food environments is that each clues our brain about eating norms, and our brains love norms. When eating with a friend that is a member of the 'clean plate plus dessert' club, you will be more likely to follow their lead. If an enormous plate of food is plonked in front of you three times a day, you will develop a psychological sense that this is what should be eaten. This is probably what accounts for the washing powder effect too - a larger packet suggests a larger use norm.
So, what is the practical, take home message? If you want to change the volume of what you eat, control your environment as best you can. Willpower won't work for long if everything else is making your subconscious want more food. Make food less visible and more effortful, don't have junk in the house, develop strategies for eating out, minimise distractions when eating, monitor your portion sizes, reduce the perception of variety and use a smaller plate to make your meal look larger. Over time these things make a big difference, and you don't even have to try too hard.
Do you use any tricks to deal with the situations mentioned in this post?
I'd love to hear about it. Comment Me.
Ref: Wasnick, B. (2002) Environmental factors that increase food intake and consumption volume of unknowning consumers. Annual Review of Nutrition, 24, 455-479.