Understanding eating interventions through an evolutionary lens

ABSTRACT

Health psychologists aim to improve eating behaviour to achieve health. Yet the effectiveness of healthy eating interventions is often minimal. This ineffectiveness may be in part because many healthy eating interventions are in a battle against evolved mechanisms (e.g., hedonic and related systems) that promote the consumption of energy-dense foods. Such foods, once rare, are now abundant in our obesogenic society, and consequently the evolved desire for energy-dense foods can now easily lead to the overconsumption of sugary, processed, and unhealthy foods. However, humans have other evolved mechanisms that also impact eating behaviour. In this article, therefore, we review eating interventions through an evolutionary lens, and describe evolved mechanisms that are relevant to eating behaviour. We discuss how using this lens could help health psychologists design more effective eating interventions and policies. By learning to work with human nature, eating interventions can more effectively promote healthier eating and healthier lives.

KEYWORDS:

• Nutrition
• eating
• evolution
• health psychology
• evolutionary psychology

Acknowledgement

The authors gratefully acknowledge the members of the Dieting, Stress, and Health (DiSH) and Haselton laboratories for their comments on drafts of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

A. Janet Tomiyama http://orcid.org/0000-0002-2152-5813

Notes

1. We use the term ‘evolved mechanism’ because we do not posit that each mechanism in our framework is a unique, food-specific adaptation (a characteristic that increased survival and reproduction in the ancestral past). Some mechanisms may, indeed, be food-specific adaptations, whereas others may be byproducts of non-food-specific adaptations or of other chance factors (Buss, Haselton, Shackelford, Bleske, & Wakefield, 1998; Futuyma, 2009). Rather than focusing on the debate about what is and is not an adaptation, we therefore use the broader term evolved mechanism, defined as a characteristic that developed as one of the following: a food-specific adaptation, a byproduct of a non-food-specific adaptation, or a result of chance factors such as phylogenetic legacy, drift, or mutation (Buss et al., 1998).

2. We acknowledge there are many healthy foods and that a variety of foods are essential for human health. However, we use this definition of ‘healthy’ because the aim of this article is ultimately to help the public eat healthier, and there is no debate that, on average, individuals in modern, industrialised nations underconsume vegetables and overconsume sugary, processed foods (Smith, Guenther, Subar, Kirkpatrick, & Dodd, 2010).

3. The bitterness of some vegetables is another likely factor in children’s vegetable avoidance, as bitterness can signal toxins that could be dangerous to small bodies (Cashdan, 1998). However, distaste for the bitter flavour does not account for the avoidance of all vegetables, such as sweet vegetables, and although bitterness may underlie children’s initial avoidance, neophobia likely perpetuates it (Cashdan, 1998).