Few national health issues in the United States are as serious and as urgent as the obesity epidemic.
The condition is easy for anyone to diagnose, but treatment for obesity continues to frustrate obese individuals and treatment professionals alike. Much of the problem stems from the fact that the exact nature and causes of obesity are still uncertain.
Is obesity a biological disease, genetically predetermined and inherited? Is it the product of a dysfunctional society, in which activity is undervalued and nutrient-poor foods are prized for their taste and convenience? Is obesity a matter of personal responsibility, affecting people who make poor choices about their diet and exercise habits despite the consequences?
With each of these possibilities, the onus falls on a different sector of society to provide a solution. If obesity is a biological disease, can scientists and doctors find an effective treatment? If obesity is a social problem, the responsibility lies predominantly with policy makers and other leaders of society to change the ways in which food and activity are make accessible and attractive to the population. Or do individuals simply need to stop searching for excuses and change their personal habits?
A new hypothesis
The truth is most likely a mixture of all three of these factors and solutions. A tendency toward obesity has been shown to have the same hereditability as height, demonstrating that obesity is genetically determined to a certain extent. Both the Food and Drug Administration (FDA) and the National Institutes of Health (NIH) have stated that obesity should be considered a disease. Nevertheless, a good diet combined with exercise is currently the only reliable way to go from obese to a healthy weight.
This is a relatively straightforward solution, but sticking to a healthy diet has proved to be extremely challenging and frustrating for many people, from those who are obese to those who are just hoping to shed a few pounds. The fact that so many people continue to eat unhealthy foods when they know it puts their health at risk has led researchers to explore a new possibility: could obesity be the result of an addiction?
Evidence for food addiction
The parallels between the drug-seeking behavior of addicts and the food cravings, overeating and disregard for healthy dietary guidelines that overweight or obese people exhibit have long been apparent. However, the concept of food addiction presents difficulties that many addiction hypotheses do not face. Human beings need to eat, and we experience hunger when we have gone too long without ingesting any food. When attempting to identify genuine food cravings, researchers need to be able separate what behavior is the result of the biological need to eat, and what may be addictive behavior.
Furthermore, eating food is often a pleasurable experience, and certain foods are especially attractive to our senses of taste and smell. Researchers also need to be able to identify the difference between liking a food and craving a food. Fortunately, brain-imaging technology now permits researchers to view the neurological activity of their subjects and to compare the active areas to the areas that are active in the brain of a drug addict.
What they have found is that there is a great deal of neurochemical similarity between the cravings that drug addicts experience and food cravings. As in drug addicts, the dopamine-reward sensitivity in the obese becomes dulled. As a result, cravings continue to be present and grow stronger while the messages that the craving has been satisfied grow weaker. One such study appeared in the Journal of Nutrition, and this study also found that its subjects reported craving the dietary supplement beverage on which they were placed in spite of the fact that they did not enjoy it.
If the evidence for the addictive properties of food continues to grow, it opens up new possibilities for treating obesity-one in which overeating and obesity are viewed as symptoms of an underlying mental disorder and treated accordingly.