Eating on Autopilot.
The first thing to remember is that we eat on autopilot. Remember the story of the tomato soup in Newsletter #021. Brian Wansink , asked people to eat a bowl of Campbells Tomato soup. Unbeknown to the poor respondents the bowls had been doctored. They could be topped up from the bottom invisibly. However much people ate, the level of the soup did not go down. Many people just kept eating, on autopilot. They did not notice the fact that they were eating vast amounts of soup. On average they ate seventy five percent more soup than those respondents without a self-filling bowl.
Beware of big plates
We are conditioned by habit. We seem to always want to empty our plates or bowls. Unfortunately, the bigger the bowl or plate the more we eat. Respondents were offering free popcorn when they went to the cinema. There were two different sizes of tub for the popcorn. One was one hundred and twenty grams and the other twice as big. The quality of the popcorn was also varied. It was either fresh or two weeks old. When respondents left the cinema, the researchers weighed the buckets again. They could see how much each person had eaten whilst watching the film. When fresh popcorn was presented in the big bucket, people ate on average ate fifty percent more . People even ate a third more unappetizing popcorn when given a big bucket of it! We are susceptible to the size of the bucket from which we eat.
Our Eyes Are Bigger than our Stomachs
Suppose we are given bowls of different sizes and asked to serve ourselves Christmas Pudding. The larger the bowl the more we tend to take. This is an example of the Delboeuf optical illusion. This was discovered in 1865 by a Belgian philosopher called Joseph Delboeuf. A circle appears to be smaller when surrounded by a much larger concentric circle. It appears to be bigger than when surrounded by a circle only slightly larger than itself. It works for food on a plate as well.
The colour of the plate and the table cloth can influence how much we chose to serve ourselves. If there is a high degree of contrast between the plate and the cloth it will stand out. The white plate on a blue table cloth in the picture for example. The outer ring of the illusion stands out more. Placing a white plate on a white table cloth makes it “disappear”.
If the plate is the same colour as the meal, we tend to serve ourselves more. If we eat tomato pasta on a red plate the contrast is reduced and the Delboeuf effect is lessened. We serve ourselves less if the same red pasta is on a white plate. The contrasting colour of the plate creates a concentric ring around the pasta. This makes the portion seem bigger. We therefore stop loading our plate. Interestingly these effects are influenced by how hungry we are. If we are hungry the effect disappears!
Alcohol consumption is higher in a loud versus quiet bar. One explanation is the work of Lorenzo Stafford of the University of Portsmouth. In a study he had people drink vodka-based drinks of different strengths. This must have been very popular with his student respondents! They did this whilst listening to music at different intensities. Above eighty decibels, respondents lost the ability to tell how strong a drink was.
In some situations, we go out with our friends. We shop together, drink together and eat together. Researchers have studied such group dining experiences. They have shown how eating as a group can impact on our perceptions of the quality of the food and our behaviour. For example, the individual called upon to give their menu selections first tends to rate the food more favourably. Other people may then mimic those choices or even the way other people are eating. If everyone is nibbling their food we tend to do the same. In general, eating with friends is not good for our waistlines. We eat thirty five percent more food than we would eating alone, when we eat with even one other person. When four of us eat together, all of us will eat seventy five percent more. With seven we eat almost twice as much.
Too Much of a Good Thing
Blowing the smell of fresh baked bread out of the bakery would seem at first sight to be a good idea. It is a strategy used for many years to attract customers. However, it seems that the strategy can backfire, if the scent lasts for too long. This was tested in studies in a school canteen and a supermarket. The scent of cookies and pizza seem to be having the opposite effect to expectations. The impact depends on the length of exposure. Beyond two minutes waiting in the fresh cookie queue, the sale of cookies went down not up. The smell was satiating the shoppers. If students waited in the canteen for too long to be served, pizza scent reduced pizza sales.
An Christmas Meal
The science can tell us how to avoid over-indulging. The first thing to do to save your waistline is to eat alone. Family meals will encourage you to eat more. Since contrast is important white plates on a black table cloth would be best. Stay away from any plate into which Christmas lunch can “fade”. Avoid the temptation of big serving dishes and plate you food.
There can be no Christmas Carols over lunch of course. This might distract you from the strength and quantity of wine you are drinking. Since food smells can with time satiate you, eat in the kitchen. To avoid autopilot eating count the number of times you chew each mouthful.
All of which sounds like no fun at all. The alternative is ignore the science, thoroughly enjoy yourself and go on a diet in the New Year. I certainly will.
A VERY MERRY CHRISTMAS.