The mental effect of foods

Uwe Geier

Who is not familiar with the effect of cream? But how can we describe that impression? Settling down in a cosy armchair – or enveloping, warming, relaxing? Well, actually... creamy. The rousing, stimulating action of coffee is also familiar to everyone. That is traced back to the caffeine component. There is also caffeine in tea which makes us alert but in quite a different way from coffee. How can we describe the differences? 

Everyone is familiar with such effects of foods which go deeper or are more sustained than taste, effects which act on our physical and mental state.

Only we do not talk or write much about them. That is why we do not have the concepts to describe such effects. In other cultures, such as in India, the idea that foods exercise a differentiated effect on the body and spirit is still widespread. But does this aspect of eating have any significance beyond our personal preferences? Are foodstuffs not sufficiently described by their substances, taste and the individual studies on their health effects?

Hyperactivity for drinking

An example: in 2007 Donna McCann and her team from Southampton University published a study in the respected journal The Lancet on the effects of artificial food colourings and preservatives on the behaviour of children. Mixtures of the substances in the study – common in so-called soft drinks or fruit gums – caused effects of hyperactivity in the 300 three-year-olds and eight and nine-year-olds. The results were so unambiguous that the EU had to respond – not with a ban but with a warning which has been on such products since 20 July 2010: “May have effects on activity and attention in children”.

Fast food to make you sleepy

Another dimension of the subject is shown by studies on the effects of various types of midday meal on the performance of pupils. The promises of an organic caterer in Bochum, for example, were put to the test by a television station. The concentration and memory retention of a school class was tested 45 minutes after lunch. Fast food was served on one day and the caterer’s whole-food menu the next. With the organic whole-food menu, memory performance rose from 42 to 61 percent and concentration from 33 to 79 percent (

There is growing interest in science in food-induced emotions. Here are a few representative examples.

Does fish make you happy?

Are substances or foods with presumed or proven effects on health also good for the soul? Take the omega-3 fatty acids contained in fish and also milk products which are supposed to be beneficial in preventing cardiac and circulatory diseases. In New Zealand – a country with low fish consumption and a high depression rate – researchers in 2002 investigated the connection between both phenomena (Silversand & Scott). And it did indeed turn out to be the case that people who ate a lot of fish viewed themselves as being mentally healthier than people who ate little or no fish. The researchers attributed this to the omega-3 fatty acids. Against the background of these results Beezhold et al. (2010) asked the question whether vegetarians did not display a correspondingly more negative mental state. Interestingly, however, they displayed a better mood in the survey than the control group – contrary to the expectations of the researchers.

This shows that simple conclusions about the connection between the consumption of fish, omega-3 fatty acids and mental state are not possible.

Pizza, chocolate and ice cream

In current basic research about food-induced emotions, it is remarkable how often coffee, pizza, ice cream and, above all, chocolate are used as samples. It is not possible to draw far reaching conclusions about our nutrition on that basis (it probably say more about the preferences of the researchers), but we can sometimes learn something about the interaction between eating, sensory impressions and the psyche. Thus Walla et al. (2010) investigated the intensity of shock reactions caused by a loud noise after eating various foods. The remarkable thing was the gender differences. Women relaxed well after yoghurt and chocolate whereas there was no effect in men.

Marketing research has also discovered the connection between emotions and food. One example is the work of Thomsen et al. (2010). Subjects were asked which of a specified set of emotional terms they associated with eating nine dark chocolates. The criteria specified, such as luxurious, arrogant, strong or traditional, indicate one way of interpreting food-induced emotions: what associations are prompted by the food? Associations can be prompted both by the effect and by memories, personal preferences and social background. In any event, the subjects were able to differentiate the chocolate in this way.

If we look at the current research about food-induced emotions in summary, it becomes clear (Hermann 2011) that associations and actual effects are rarely separated. A lot of the work is done with convenience products (ready-meals) and luxury foods. There are largely no insightful studies about basic foods.

A psychological test for foods

At our institute we have for years used the experience of trained self-observers for research into foods. We know from many seminars how quickly untrained people mostly learn to perceive the effect of food on their mood. It is all the more surprising, therefore, that in the academic discipline which supplies methods of self-observation, namely psychology, there is no test procedure for foods among the hundreds that are available.

For this reason we set out in 2010 to develop a corresponding test ourselves. A good starting point is sensory evaluation, the science of taste. There are various sensory evaluation tests which are defined by international standards. We found a professional partner for our experiments in the Technology Transfer Centre in Bremerhaven.

Our first test question was whether untrained people, in this case consumers of organic food, are able to identify the effect which foods have on them. The second was whether the test subjects could succeed in discovering more subtle differences.

In the same way as in a consumer test, the 60 test subjects were each given encoded samples in random order. The test subjects sat in a cabin under defined conditions. Three to four samples each were tested in the six experiments. The subjects were given a questionnaire with six polar questions: Do you feel more calm or restless, awake or tired, warm or cold, upright or stooped and in a better or worse mood? The questionnaire was to be completed in 25 to 30 minutes.

To my surprise the test subjects were able clearly to identify some differences: after potatoes they felt more tired but calmer, in this instance in comparison to carrots and tomatoes. Milk produced an impression of warmth and calm in contrast to soya milk. These are some of the findings which now have a scientific basis.

There was also an indication that the test subjects were able to differentiate between the origin (Demeter, organic, conventional) of otherwise comparable milk and the breeding method of carrots (biodynamic or F1 hybrids). These six experiments are only the first step in the development of a standardised procedure for evaluating the psychological effect of foods. We hope to publicise the topic with the “quick test” we are developing and to obtain a simple but reliable instrument for practical research. Further tests are planned in the near future to make the test more precise. We also intend to investigate the extent to which taste and its effect on mood are connected and whether the results of self-observation in the test (for example, “I feel more alert”) can be confirmed in behavioural tests.

A new chapter in the evaluation of foods

There are considerable differences in the way that our food is produced: from the husbandry of the animals, their feed and the fertilisation of plants through many influences in processing to packaging. Is it possible that gentle or destructive processing, humane or cruel animal husbandry, natural or artificial additives can have an effect which reaches as far as our physical and mental mood after consumption of the products? There are some indications that this might be the case.

We estimate the scope of future applications to be very great. What do I provide as a company or school in my canteen? Which foods support or hold back, and if so, what? Which foods are best for what purposes? How significant are individual needs? These are questions which require an answer.

Irrespective of the circumstances in which the planned test procedure is applied: research shows that foods influence our psyche and the way we feel physically – independently of enjoyment and personal preferences. This is where our concept of food must be extended.

Science works slowly. It will be a while yet before our daily life is influenced by new methods and findings.

The good news is, however, that you can do these things yourself. With a bit of tranquillity and inner attentiveness, you can begin to get an impression in one or two minutes. It helps to make comparisons and discuss them. If you are surprised by your own observations, that is a good sign of your own neutral perception. There is a lot to discover here.

About the author: Dr. Uwe Geier, Forschungsring für Biologisch-Dynamische Wirtschaftsweise e.V., Brandschneise 5, 64295 Darmstadt, Email: