“hedonic hunger” – yes there is food addiction
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”.
“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.
Physiol Behav. 2007 Jul 24;91(4):432-9. Epub 2007 Apr 12.
Department of Psychology, Drexel University, Philadelphia, PA 19102, USA. firstname.lastname@example.org
An increasing proportion of human food consumption appears to be driven by pleasure, not just by the need for calories. In addition to its effects on body mass and health, the food environment in affluent societies may be creating an appetitive counterpart to the psychological effects of other hedonically-driven activities such as drug use and compulsive gambling. This phenomenon is referred to here as “hedonic hunger.” Animal literature is reviewed indicating that brain-based homeostatic and hedonic eating motives overlap but are nonetheless dissociable. In humans there is evidence that obese individuals prefer and consume high palatability foods more than those of normal weight. Among normal weight individuals it has long been assumed that the appetitive anomalies associated with restrained eating are due to diet-induced challenges to the homeostatic system, but we review evidence suggesting that they more likely stem from hedonic hunger (i.e., eating less than wanted rather than less than needed). Finally, a recently-developed measure (the Power of Food Scale; PFS) of individual differences in appetitive responsiveness to rewarding properties of the food environment is described. Preliminary evidence indicates that the PFS is reliable and valid and is related to clinically-relevant variables such as food cravings and binge eating. This measure, combined with environmental manipulations of food availability and palatability, may constitute a useful approach to studying hedonic hunger.
Physiol Behav. 2005 Sep 15;86(1-2):1-4.
NIH symposium series: ingestive mechanisms in obesity, substance abuse and mental disorders.
Drexel University College of Medicine, Department of Pharmacology and Physiology, MS488, Philadelphia, PA 19102, USA. Simansky@Drexel.edu
This report summarizes the background and specific objectives for a symposium on the neurobiology of nonhomeostatic eating and drug abuse that was held at the 2004 Annual Meeting of the Society for the Study of Ingestive Behavior (SSIB). The symposium was the first of a series funded by a conference grant from four institutes of the National Institutes of Health. The encompassing goal of the series is to analyze the roles for the biological mechanisms of ingestion in obesity, eating disorders and other theoretically related areas including addiction, depression and schizophrenia. The symptoms and treatments of these diverse pathologies routinely involve aberrations in the mechanisms regulating eating and body weight. The presentations and discussion from this symposium (1) identified changes in neurotransmitter dynamics and gene expression in brain “reward circuits” accompanying learning of behaviors to obtain palatable foods or drugs of abuse; (2) analyzed behavioral findings in animals and humans, and neuroimaging data in humans, supporting treatment with GABA(B) agonists to reduce craving for drugs of abuse and possibly for highly rewarding foods; and (3) used neuroimaging data in humans to establish novel serotonergic targets for normalizing reward processes and impulse control in anorexia nervosa and bulimia. Overall, the symposium clearly revealed our rapidly broadening understanding of the alterations in the brain at the molecular, cellular and systems levels that are associated with craving and nonhomeostatic consumption of food and drugs of abuse. This knowledge gained largely in animal models translates to novel and better strategies for treating human patients.