Mindless eating

Dear colleagues,

You eat until you're full - right? You eat what you feel like eating - right? Actually, wrong, according to Brian Wansink, who has researched people's eating habits for many years. His book Mindless eating: why we eat more than we think (New York: Bantam, 2006) is a popular account of research on eating. The findings are astounding.

Wansink's research team has a special restaurant. Customers receive identical meals except for small details. In one experiment, everyone received a complimentary glass of wine. Half the diners were told it was Cabernet Sauvignon from Noah's Winery, a new California winery, whereas the other half were given the same information except for one detail: Noah's Winery was said to be in North Dakota. The investigators later weighed how much food the diners left behind. The diners told the wine was from California ate 11% more food and spent more time over their meals. Incidentally, the wines provided to all diners were identical cheap plonk.

Subtle details can affect your appetite. The same amount of food looks bigger on a small plate so you'll need less to feel full. So if you want to lose weight, eat from smaller plates.

But surely you, a discerning eater, wouldn't fall for something like this. Think again. "In the thousands of debriefings we've done for hundreds of studies, nearly every person who was 'tricked' by the words on a label, the size of a package, the lighting in a room, or the size of a plate said, 'I wasn't influenced by that.' They might acknowledge that others could be 'fooled', but they don't think they were. That is what gives mindless eating so much power over us - we're not aware it's happening" (pp. 23-24).

In the bottomless soup bowl experiment, students were given large bowls of tomato soup and invited to eat as much as they wanted. Some of their bowls had a hidden tube at the bottom attached to a larger bowl in the kitchen, so when they ate the level decreased more slowly than according to what they actually ate. In 20 minutes, those eaters ate much more soup - 73% more - but estimated they had eaten the same amount as those with normal bowls, namely half a bowl. The implication: how much you think you've eaten is more affected by sight - the level in the soup bowl - than stomach.

Experimenters provided complimentary bowls of chocolates for secretaries. Sometimes the bowl sat on the corner of their desk, other times in a desk top drawer and yet other times in a filing cabinet a couple of steps away. The more convenient the chocolates, the more were eaten. Every time you notice the chocolates, you have to make a decision not to eat one, and the more decisions you have to make, the more likely you are to give in.

People have been observed using their refrigerators. They are more likely to eat the foods at the front in plain view. You can encourage family members to eat better by putting healthier options - apples and carrots - within easy reach.

What you think you're eating influences what you taste. Wansink reports on a World War II US navy cook, Billy, who mistakenly ordered two huge lots of lemon jello and no cherry jello for a long cruise. After a couple of months, the sailors made vociferous complaints about the lack of cherry jello. Billy came up with a solution: he served lemon jello with red food colouring. All the sailors thought it was cherry jello; Billy even received some compliments. Wansink has done experiments that show the same thing: what people think they're eating affects what they taste.

Mindless eating is filled with fascinating stories of experiments and their implications. For example, people at a restaurant eat more when they're in a group: the larger the group the more each person eats. People will rate a restaurant more highly when the menu uses descriptive names, for example "Traditional Cajun Red Beans with Rice", compared to simple names such as "Red Beans with Rice" - and they rate identical food more highly when it has more attractive labels.

The implications are as simple as they are unpalatable. People think they are the ones in control of their eating but actually nearly everyone is influenced by subtle cues. Of course the masters of manipulating these cues are food manufacturers, supermarkets and restaurants. The average customer has little hope in the face of this.

Is education the solution? No. Wansink has done experiments showing that even well-informed eaters are highly susceptible to cues. He instead advocates "reengineering": taking action to change the cues around us. An example is not to pour breakfast cereal out of a large box, but instead - in advance - put it into small containers. You'll eat less as a result.

Wansink recommends designing doable changes, such as applying the rule that half of every plate of food should be salad or vegetables, and keeping a daily checklist of when you've followed the rule. He says three changes are enough to keep track of. His aim is the "mindless margin", a small change in your daily food intake that isn't enough to notice, but which over a year can make a difference. Wansink thinks behaviour change is the wave of the future.

Mindless eating is entertaining and sobering. Read it - but not while sitting with a box of snacks.

Brian Martin
20 October 2008

Thanks to Kate Bowles for valuable comments on a draft.

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