Drexel University’s Dr. Michael Lowe, professor of psychology, has taken a closer look at existing studies on food intake and human behavior and found an increasing proportion of food consumption appears to be driven by pleasure, not just by the need for calories. Among some people living in affluent societies, the food environment may be creating a form of appetitive drive similar to that produced by other pleasure-driven activities such as drug use and compulsive gambling.
The phenomenon is referred to by Lowe and co-author Meghan L. Butryn, research assistant professor at Drexel, as “hedonic hunger” in a paper they published in the 2007 edition of Physiology and Behavior.
“This is not a new study, but a review of previous studies that suggests a novel perspective on eating habits and appetite,” said Lowe. “We agree with other observers that this phenomenon is contributing to escalating obesity and its medical comorbidities. However, we also propose that the food environment may be creating an appetitive counterpart to the psychological effects of other hedonically-driven activities such as drug use and compulsive gambling.”
A review of studies in animals showed that homeostatic (i.e., eating because of physical need) and hedonic (eating for pleasure in the absence of need) eating motives overlap but are nonetheless separable. Just as compulsive gamblers or drug-dependent individuals are preoccupied with their habit even when they are not engaging in it, some individuals may experience frequent thoughts, feelings and urges about food in the absence of any short-or long-term energy deficit.
The researchers show how delicious food can itself create powerful motives to keep eating it, much like more traditional addictive substances. In environments where such foods are always available, such motives may continue to manifest themselves in food-related thoughts and urges even when we are away from food. The smell of freshly baked doughnuts can entice someone to stop at a bakery and eat the doughnut or the sight of a dessert can attract a person to eat even when physically full after dinner. Once such habits are firmly established, trying to change them may not be a matter of “just saying no;” rather, such discontinuation may produce withdrawal responses not unlike stopping some drugs of abuse.
Traditionally, it has been thought that food is a form of self-medication for stress or boredom, but the Drexel researchers are suggesting looking beyond psychological factors when studying the facts behind superfluous eating. For one, rather than viewing such eating as pure indulgence, the Drexel researchers suggest that eating for pleasure may have been an evolutionary adaptation that helped us survive periods of food scarcity in the distant past.
In a recent study done at Princeton University, rats were given periodic access to sugar water in addition to their normal lab rat chow. When the sugar water was suddenly discontinued, they showed behavioral and neurochemical signs of withdrawal similar to those shown when drugs are withdrawn from drug-addicted rats.
“If these results can be generalized to humans, they suggest that palatable foods may create powerful motivations to eat not only because their taste is rewarding but because their consumption prevents the anxiety or stress that would occur if they were not consumed,” said Lowe.
According to the Drexel researchers, most normal-weight restrained eaters are trying to control their food intake not to lose weight but to prevent overeating and weight gain. It is logical to expect that the combination of a susceptibility toward overeating and conscious efforts to avoid overeating would result in more frequent instances of “hedonic hunger.”
“The combination of an environment filled with highly palatable foods, and cultural norms that make these foods ‘psychologically available’ around the clock may paradoxically be a perfect recipe for the generation of both epidemic obesity and widespread hedonic hunger,” said Lowe.
A professor in the department of psychology, Lowe is also a research associate at the Renfrew Center for eating disorders in Philadelphia. The focus of his research is eating and weight-control regulation among dieters, obese individuals and those with eating disorders.
Lowe is a member of the Scientific Advisory Board for Weight Watchers International. He is an associate editor for the Journal of Abnormal Psychology and served on its editorial board, and chaired the Obesity and Eating Disorders Special Interest Group of the Association for Advancement of Behavior Therapy.
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