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Media Type: Article - Recent
Date of Publication: September 2016
Publisher: Royal Zoological Society of New South Wales
Author(s): Graham Pyke
Journal: Australian Zoologist
Graham Pyke applies Optimal Foraging Theory to consider how human dietary behavior evolved in a foraging environment dramatically different than our current circumstances.
ABSTRACT: Optimal Foraging Theory (OFT), enables understanding of foraging behaviour, which is exhibited by all of life, through the assumption that foraging behaviour maximises some currency of foraging. OFT has been relatively successful for nectar-feeding animals, with energy the primary foraging currency, and less successful for generalist herbivores and omnivores, for which foraging currencies include nutrients. It has been extended to other areas of biology, applied to human foraging, is a strong ecological theory, and 2016 marks its’ 50th birthday. Human foraging has been affected by inter-related, recent and rapid developments of agriculture, animal husbandry, technology, social living and culture. Consequently, the foraging environment in which humans evolved is long gone, and our foraging may not be well adapted to current circumstances. Human foraging is therefore caught in “evolutionary traps”. For example, as generalist omnivores we evolved a ‘balanced diet’, commonly represented by ‘food pyramids’, reflecting how often we encountered and consumed various food types during our evolutionary past. We therefore evolved preferences to collect and consume foods high in fats, oils, sugar and salt, valuable when rare, but adversely affecting our health with increasing availability. Additionally, given diverse arrays of potential food items, we should mimic foraging behaviour of others, especially those we know, admire and trust. Consequently, we are strongly affected by cultural influences, and by advertising and marketing of food types and ‘fad diets’, especially when promoted by movie stars, sports heroes and the like. Being omnivores, animal meat will likely remain ‘on the table’ indefinitely, with consumption depending on availability, plus benefits and costs, whether real or imaginary, all ingredients of the optimal foraging approach. Of course, perceived benefits of consuming animal meat are likely to be greatly influenced through what we hear or see via others. Looking ahead, ‘zoology on the table’ will remain contentious, OFT will be significantly developed for non-human organisms with some interest in understanding human foraging, and there will be much further research on effectiveness of advertising. No doubt, we shall continue to be deluged with messages advocating what we should eat and drink, and health issues associated with non-optimal diets will persist.