It used to be thought that blue was an appetite suppressant because blue foods are rare and sometimes poisonous. But I have always doubted this and wrote about it near three years ago on this blog. And then nearly two years ago I posted about research from the University of Basel (Switzerland) and the University of Mannheim (Germany) in which it was shown that participants drank less from a red cup than a blue cup and ate less snack food from a red plate than from a blue plate. In other words, the opposite of what was commonly believed. Today I read in CNN about work by Nicola Bruno, a cognitive psychologist from the University of Parma, about his research to measure how much food or hand cream people used when presented on plates of different colours (red, white or blue). The food and hand cream was available to be used freely whilst participants took part in a survey. People ate less food and used less hand cream when either was presented on a red plate. However, the authors note that in their experiment the participants were unaware of the experiment – so it is not so straight forward to extrapolate and conclude that if you buy red plates for home you would eat less. Because then you would be conscious of the idea and it might not work. On the other hand, it might!!
It was nice for me to hear this story and it reminded me of when Nicola came to visit me (when I worked at Keele University) and we published a paper together. That was in about 2000 and I don’t think I have seen him since. Sometimes it isn’t a small world. But it was nice to come across him again anyway.
When I was young, differently flavoured crisps came in distinctly different coloured bags; plain crisps were red, cheese and onion were green and salt and vinegar were blue. Generally these colour codes are still used today – at least in the UK. However, one manufacturer (Walkers) is breaking these long-standing rules.
Research at the University of Oxford was recently reported that concludes that the colour of the bag can affect the taste of the crisps inside because of our expectations. It turns out that crisp manufacturers are putting pressure on Walkers to sort their act out and conform to the old rules.
ps. For readers in the USA, we are talking about potato chips.
The Guardian has reported that Nestlé has removed artificial ingredients from their entire confectionary range. However, I am not sure that this is worth making too much of a song and dance about. The public have a natural aversion to artificial colorants. Surely natural is better? Well, not necessarily.
The foliage and berries of the Deadly Nightshade plant are extremely toxic. Apple seeds can be fatal if eaten in large enough quantities (they contain a small amount of amygdalin). The kidney bean is poisonous if not correctly cooked. The puffafish – known in Japan as Fugu – can be lethally poisonous due to its tetrodotoxin; therefore, it must be carefully prepared to remove toxic parts and to avoid contaminating the meat. All of these things are natural.
Lots of natural products are not harmful. But there are many many artificial chemicals that are completely identical (chemically) to their naturally occurring and harmless equivalents. It’s strange that we are so keen to believe that natural is good and man-made is bad. Sometimes it is true, but sometimes it is not.