Chocolate eating styles, as defined by SCIENCE

I recently read Salt, Sugar, Fat by Michael Moss (a New York Times journalist who previously worked in Pakistan, but when his colleague David Rohde was kidnapped, the NYT transferred Moss to the safer beat of reporting on the food industry). The book provides fascinating (and sometimes horrifying) insight into the research and testing that goes into manipulating the various sensory aspects of food, and into developing food products with just the right amounts of salt, sugar and/or fat to make them incredibly alluring. Every variable in the eating experience can be fine-tuned to make food that people feel compelled not only to eat, but to eat lots of. For example, food scientists have worked out the exact amount of pressure a corn chip should break at in order to produce chips of an ideal crispness and crunchiness to maximise the enjoyment the average consumer experiences while eating (and I assume that if you buy some Doritos and eat them, you’re experiencing the outcome of that research).

Honing foods to optimise their appeal to consumers obviously requires the characterisation of many aspects of both the food and the consumers. Which is presumably how this paper, ‘Characterisation of chocolate eating behaviour’, came about, and which asks the question:

So, like, how do people eat chocolate?

You know, apart from, like, putting it in their mouth and somehow getting it down their gullet.

Turns out people fall into three distinct groups when it comes to how they eat chocolate:

1. the fast chewers
2. the thorough chewers
3. the suckers

The researchers found this out by giving the 40 study participants each two samples of milk chocolate. The samples were the same in ingredient composition and were similar in how viscous they would be when melted, but differed slightly in some textural aspects. I love this bit of the paper where the researchers say “For confidentiality reasons no further detail concerning sample composition can be provided.” So manipulation of the texture of the chocolate was a key variable being investigated in the study, but you’re being coy about how the texture differed between the two chocolate samples being tested? Well, one researcher does work for Mars and the study was funded by Mars, so omg u guyz this is a Mars chocolate formulation secret!

Anyway, the researchers have deigned to go into detail about how people ate the chocolate samples. Eating behaviours were characterised using surface electromyography (electrodes placed on the skin surface that record muscle activity) and electroglottography, which uses electrodes to record the activity of the glottis, i.e. the vocal cords. Electroglottography was originally developed for use in speech therapy, but has been re-purposed here to learn more about how and when people swallow.

The results were, firstly, that Chocolate A (whatever that was) was significantly preferred to Chocolate B (whatever that was). Participants considered Chocolate A to coat the mouth more and be softer at first bite (so hey, maybe you’re eating Chocolate A these days whenever you eat a Mars chocolate product). In terms of how the chocolate was eaten, each participant apparently had a unique way of eating the chocolate – no two participants were identical in terms of chew rate, total chewing time, number of swallows, how long it took them to get to the point of their last swallow, etc.

Cluster analysis was then performed on this information (this grouped people so that their eating behaviour was more similar to other people in the same group than people in other groups) which gives us the three styles of chocolate eating: fast chewing, thorough chewing, sucking.

If you do the cluster analysis for the data obtained for the two chocolate types separately, the same people still fall into the same eating behaviour groups, suggesting that people’s chocolate eating style is consistent across different types of chocolate. We can’t know this for sure from this study, since we don’t know how similar or different the two chocolate samples were (just that they were both milk chocolate), but maybe chocolates that are more obviously different would be eaten differently (I think my eating behaviour for a piece of milk chocolate versus a piece of, say, 80% dark chocolate is different, but maybe I’m just some weird anomaly).

And to finish, an excerpt from the paper:

“From a wider perspective, it has been shown that variation in bite size and oral processing time impacts on food intake. ‘Slow’ eating has also been shown to decrease food intake and result in increased satiety. If variation in chocolate eating behaviour exists then this could also impact on chocolate intake levels which in turn may have health implications.”

If we make those assumptions, this presents rather a quandary to Mars: Chocolate A was much preferred by participants compared to Chocolate B, but participants also took longer to eat Chocolate A, which might mean that people would eat less of it. What do you do, Mars? What do you do? (Presumably some more testing and then whatever option seems most likely to give them the best profits.)

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