“We eat first with our eyes” – Apicus
From an evolutionary point of view, finding nutritious food sources is essential. While today, our foraging consists of walking down the aisle at the supermarket, in our not-so-distant past, foraging relied primarily upon vision to find the plants and animals we had already discovered to be, if not totally beneficial, not harmful. Some evolutionary biologists believe our trichromic vision was an adaption that facilitated the identification of energy-rich and coincidentally red fruits among the sizeable green background. [1]
While the senses of taste, smell, and texture are the ultimate arbiters of a food’s palatability, our vision provides the most effective means of identifying and predicting what’s for dinner. Unsurprisingly, our neurologic underpinnings, structural and “processing,” are optimized through attention, pleasure, reward, and disgust to help in food selection. And as it turns out, these drives are heightened when we are “in a hungry state.”
Of course, today’s foodscape is nothing like the Savannah where many of our instinctual behaviors developed. Food scarcity has given way to, in many instances, an overabundance. Meanwhile, cooking has become less of a skill or craft and more of cultural phenomenon. The how-to of Julia Childs has given way first to celebrity chefs, remember Emeril – Bam!; to The Chef’s Table, beautifully crafted documentaries of food culture featuring artfully plated dishes. The rise of social media and the camera incorporated into the ubiquitous cell phone has given rise to many “look-at-me” images of fine dining and diners. [2] There is a whole industry of food photography, amateur and professional, in some instances approaching “food porn.”
This preamble leads us to the question asked in a thought piece in Brain and Cognition that begins by defining and describing “visual hunger.”
“Our brains learnt to enjoy seeing food, since it would likely precede consumption. The automatic reward associated with the sight of food likely meant another day of sufficient nutrients for survival, and at the same time, the physiological responses would prepare our bodies to receive that food. Our suggestion here is that the regular exposure to virtual foods nowadays, and the array of neural, physiological, and behavioural responses linked to it, might be exacerbating our physiological hunger way too often.”
Intriguing yes? Here are some of the facts the authors use in making their case.
Let us begin with a paradox. As the researchers write, “exposure to images of desirable foods can trigger inhibitory cognitive processes such as self-restraint,” we resist temptation. On the other hand, food advertising increases our desire and consumption of food. The presence of “visual hunger,” prompted by all those appealing images, acts like our physiologic hunger, overcoming our resistance and letting us yield to those oh-so-tempting, delicious-looking calories. Ironically, we see this in the spate of lawsuits against fast food purveyors over their food images.
“In the ads, burgers look tall, heaped with meat and cheese, topped with golden, rounded buns. But in the photos of burgers bought from a real fast food location, they’re flat, with meat and cheese barely peeking out of limp, white buns.”
- Individuals with binge-eating disorders and bulimia “show greater reward sensitivity and brain activation when viewing images of food.”
- “Healthy weight” individuals activate the areas associated with cognitive control.
- Obese individuals show less activation in the reward-related brain areas, with “greater activation in gustatory cortex and somatosensory regions when anticipating food intake.” [emphasis added] – the reward is the anticipation, not the sensory experience of the meal. That anticipation includes activating executive function, decision-making, and motor areas involved with hand-to-mouth movement and swallowing.
- The brain is the most voracious of eaters, consuming 25% of our energy on average and cranking up even more at the sight and smell of appetizing food. Despite our belief that we are multi-taskers, the brain “directs its limited attentional resources toward the processing of high-fat foods.” The brain locks in those foods within 165 milliseconds of being seen, long before we are conscious of what the image depicts. Both hunger, physiologic or visual, as well as greater BMI, promote that response.
- · Anticipation also impacts our brain activity. Individuals with a higher BMI show greater activation in brain areas related to cognitive control and reward anticipation when thinking about the pleasure of eating healthy foods. When considering the health benefits of nutritious foods, those with higher BMI show less activation in these areas.
- Like Pavlov’s dog, food images associated with anticipation bring out anticipatory physiologic responses, including salivation, heart rate increases, and insulin release.
“As advanced in this article, the regular exposure to virtual foods might well be exacerbating our physiological hunger more often than needed, due to the array of neural, physiological, and behavioural responses linked to seeing food.”
Our modern foodscape is far different than the one we evolved on. Our inherent response to food, especially our visually mediated responses, may be no longer in sync with our “built environment.” That includes energy-dense, hyper-palatable foods and foods that, with processing, have long shelf lives, allowing them to be distributed globally irrespective of season. Our old innate ways make us less “fit” for the environment we have created. While education, labels, and taxes are all promoted to nudge our behavior, perhaps fighting “human nature” is too challenging for most of us. We may be better served by channeling our innovation to alter the food landscape.
As our brains evolve to crave what they see, the line between appetite and indulgence becomes dangerously blurred. With ubiquitous visual triggers, the challenge is understanding how deeply embedded these cues are in shaping our desires. Maybe it’s time we reconsider how food images influence our diets and our perception of hunger.
[1] The color red causes a physiologic increase in our heart rate and begins to prepare the digestive system for a meal.
[2] As a foodie, I will confess to a few food photos. Oddly, with time, I found it hard to remember what the dish actually was.
Source: Eating with our eyes: From visual hunger to digital satiation Brain and Cognition DOI: 10.1016/j.bandc.2015.08.006
Chuck Dinerstein, MD, MBA
Director of Medicine
Dr. Charles Dinerstein, M.D., MBA, FACS is Director of Medicine at the American Council on Science and Health. He has over 25 years of experience as a vascular surgeon.
