Brain Evolution, the Determinates of Food Choice, and the Omnivore's Dilemma

Abstract

A coevolutionary paradigm using a biocultural perspective can help to unravel the complex interactions that led to the contemporary pattern of eating. Evolutionary history helps to understand the adaptation of diet and its nutritional implications. Anatomical and behavioral changes linked to changing dietary patterns in the Paleolithic resulted in an adaptive framework that affects modern diet. The evolution of an expanding brain, a shrinking large intestine, and lengthening small intestine necessitated a demand for nutritionally dense foods. The key to these changes is an understanding of the response to the omnivore's dilemma. Omnivores in their search for new items to feed their varied diet (neophilia) have a challenge when they fear (neophobia) novel items that may be poisonous and can cause death. The inborn mechanism initiates palate fatigue (sensory-specific satiety) ensuring a variety of foods will be eaten. Variety will limit the impact of toxins ingested and provide a more balanced diet. The development of cuisine, a momentous event in history, mediated the conflict, and changed the course of human evolution. The cuisine, a biocultural construct, defines which items found in nature are edible, how these products are transformed into food, the flavors used to add a sensory dimension to foods, and rules of eating or etiquette. Etiquette defines how, when, and with whom we eat. Patterns of eating in the modern setting are the end product of the way that Homo sapiens evolved and resolved the omnivore's dilemma. Control of fire and cooking expanded the range of available foods by creating a class of foods that are "predigested." An essential element to the evolution of the human diet was the transition to agriculture as the primary mode of subsistence. The Neolithic revolution dramatically narrowed the dietary niche by decreasing the variety of available foods, with the shift to intensive agriculture creating a dramatic decline in human nutrition. The recent industrialization of the world food system has resulted in a nutritional transition in which developing nations are simultaneously experiencing undernutrition and obesity. In addition, an abundance of inexpensive, high-density foods laden with sugar and fats is available to a population that expends little energy to obtain such large numbers of calories. Furthermore, the abundant variety of ultraprocessed foods overrides the sensory-specific satiety mechanism leading to overconsumption.

Snack Food, Satiety, and Weight

“…From an evolutionary perspective, humans historically consumed a wide variety of foods in relatively small quantities to obtain a diversity of required nutrients, vitamins, and minerals while limiting the amount of toxins in the foods (27,28). However, in today's society, increased variety has been shown to increase food consumption both during an eating occasion (e.g., at a birthday party or wedding) and across meals (29,30).…”

“…For example, Raynor and Epstein (31) found that when participants ate a highly palatable snack 4 times/wk for 8 wk, their hedonic ratings (i.e., the extent to which the snack tasted pleasant) decreased. This poses a particular challenge to consumers when exposed to the ubiquity and overabundance of highly processed snacks that offer variety on the basis of added fat, sugar, salt, and spices (28).…”

The endocrinology of taste receptors

“…The ability to interrogate sweet and bitter tastants when presented side by side in the wild enables primates to differentiate between bitter (poisonous or rotten vegetation) and sweet (ripe and usually non-poisonous vegetation) is evolutionarily critical to survival. 76 This process is only one of several adaptive mechanisms to ensure that bitter taste is paramount. 77 …”

Nutritional psychiatry research: an emerging discipline and its intersection with global urbanization, environmental challenges and the evolutionary mismatch

“…Ancestral diets were also united by their absence of highly processed foods containing high sodium, added fats and refined sugar. In other words, the anthropological evidence concerning ancestral diets indicates that their regional and seasonal differences were minor compared to the ways in which they differ from the modern nutritional landscape [214,215]. With this in mind, we can move toward discussions of evolutionary perspectives and epigenetic opportunities.…”