A Focus On: Hedonic Eating
Image: fMRI images from individuals showing robust activity in brain regions that encode pleasure and reward during consumption of palatable food. Image courtesy of Kyle Berger, University of North Carolina, Chapel Hill
In answering the question of why we eat, the initial response seems obvious - to obtain energy to support our everyday activities, and ultimately, to promote our survival. However, many of our modern day food choices suggest the possibility of another answer that may threaten our health and functioning. Increasingly, the reason we eat has less to do with sustenance and more to do with how certain foods and drinks taste. Moreover, our food choices are influenced by a multitude of other factors, including social situations, money, advertising, sleep schedules, stress levels, and the time available to prepare and eat a meal.
Our hunter/gatherer ancestors foraged for vegetation and hunted animals to eat, and in doing so they expended energy to obtain foods that were not typically calorically dense. As a result, their energy expenditure was more closely balanced with their energy consumption. A comparison between the food landscape of our ancestors and the current environment shows changes in the energy balance equation (energy expended vs. energy consumed). Advances in agriculture and modern farming techniques have provided the opportunity to grow massive quantities of food with far less effort than before.
On the other side of the equation, there has also been a dramatic change in our food sources. Today, many food items are highly processed combinations of several palatable ingredients and chemicals. The food industry creates and markets food and beverage products that are engineered to be both desirable and inexpensive. In the process, foods such as corn and wheat are transformed from their original form and combined with salt, fat, sugars, and other ingredients to yield the low-cost, high-energy food and beverage items that line grocery store shelves.
Thus, although food is essential for life, not all foods are created equal, and eating excess quantities of certain foods can actually harm health, rather than sustaining life and promoting wellbeing. Overeating and obesity are on the rise around the world. Despite warnings of the physical health risks associated with increased body weight, the plethora of diet books and programs available, and the stigma associated with excess weight, many people find it difficult to achieve and maintain a healthy body weight. This prompts a close consideration of the factors involved in promoting weight gain or thwarting weight loss. The fact remains that the pleasurable aspects of foods are powerful motivators of our choice
Ultimately, the basic biology underlying food intake is closely linked to pleasure. Since food is necessary for survival, eating–especially when hungry–is inherently reinforcing. The issue is that eating can be reinforcing even when it is not driven by a calorie deficit. We continue to eat certain foods past the point of satiation, and why we consume foods–like cupcakes and candy–that are highly palatable yet not necessarily gratifying. Unfortunately, our natural inclination to consume these types of foods collides with the many influences in our modern food environment to ultimately encourage the overconsumption of palatable foods.
Special thanks to Ms. Susan Murray for her assistance with drafting this article.
Dr. Nicole Avena is a research neuroscientist/psychologist and expert in the fields of nutrition, diet, and addiction at Icahn School of Medicine at Mount Sinai, New York, USA.
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