Many individuals proclaim that they are “addicted to food.” Some report an inability to control their cravings, continuing to indulge in food that is knowingly making them unhealthy and overweight. Many of these individuals meet the criteria for addiction similar to those with alcohol and substance abuse disorders. The craving described is physical, yet far different than normal hunger. The brain actually responds to high-fat, highcalorie foods in the same manner as if it were exposed to a drug of abuse. Obesity is the most serious health crisis America is facing. Properly acknowledging that foods can be addictive may be one of the keys to solving this alarming trend.
The act of eating highly processed food containing sugar, fat and salt can become addictive. Compulsive behaviors arise out of a primitive neurochemical reward system in our brain that has the ability to override normal willpower, disallowing us from paying attention to the biological signals that control hunger. People don’t want to become sick, developing comorbidities associated with obesity such as hypertension, heart disease, diabetes, joint pain and cancer. Clearly something beyond weak willpower contributes to the continued participation in such detrimental behaviors.
According to the DSM-IV, the Diagnostic and Statistical Manual of The Science of Food Addiction by Lisa E. Heuer, M.D. Mental Disorders, the following criteria are assigned to substance dependence (addiction):
• Substance is taken in larger amounts and for longer periods than intended
• Persistent desire or repeated unsuccessful attempts to quit
• Much time/activity is spent to obtain, use or recover
• Important social, occupational or recreational activities are given up or reduced
• Use continues despite knowledge of adverse consequences
• Tolerance (marked increase in amount, marked decrease in effect)
• Characteristic withdrawal symptoms, substance taken to relieve withdrawal.
It is easy to see how the above criteria can apply to food addiction.
Dopamine and Overeating
Some experiments utilized PET imaging on the brains of both obese and normal weight subjects. PET imaging uses radiation to produce 3-dimensional, color images of the functional processes within the human body, in this case the brain. Not surprisingly, a very different response to food as well as pictures of food was demonstrated. Obese subjects were found to have a deficit of the neurotransmitter dopamine. Dopamine is one of the brain chemicals heavily associated with reward.
This reward manifests in a reinforcing pleasurable response. Imaging studies demonstrate that obese and normal weight subjects have a different response to the action of dopamine in the brain. Specifically, a down-regulation of the dopamine receptors in the brain (fewer receptors) of the obese subjects was reported. With fewer receptors, the pleasurable response to dopamine will be become less intense in these subjects. And with a less intense pleasurable response to the same stimulus (high fat/sugar food), an obese person would have to overeat to obtain the same reward as their normal weight peers. In essence, this overeating acts to counterbalance the lower levels of pleasure from the same food stimulus.
The Impacts of Ghrelin and Serotonin
Additional evidence above and beyond dopamine’s integral function supports the physiological basis of food addiction. Ghrelin, a hormone involved in appetite, signaling us to eat, is also involved in the reward system in our brain. When empty, the stomach produces ghrelin to communicate hunger to the brain. In many obese individuals, there is an overproduction of this hormone, resulting in increased hunger and subsequently a relentless drive to overeat.
Serotonin also has been found to be a key player in the physiological basis for food addiction. Serotonin is a neurotransmitter responsible for alleviating physical and emotional pain. Consuming refined carbohydrates such as cookies, cakes, bread, etc. has been demonstrated to increase the production and release of serotonin. Pain, both physical and emotional, will subsequently be reduced with ingestion of these substances. Individuals with lower levels of serotonin innately, or those going through stressful life events, might use these foods to “self-medicate” to increase serotonin, predisposing them to gain weight, sometimes excessively.
Understanding why an individual might become addicted to food is complex. If life becomes stressful, this vulnerable individual would perhaps rely on eating sugar and/or fat to help get through a difficult process. When we find that something seems to help our pain, be it emotional or physical, a powerful reinforcing behavior can often occur. Repeatedly calling upon these substances to relieve our suffering can lead to abuse which ultimately can become addiction. When someone cannot stop using a food substance by reason and willpower alone, this constitutes a chemical dependency on food. Food addiction is real. The good news? It also can be overcome. With the right support and tools in place, individuals can move beyond their food addiction into a healthier lifestyle.
Dr. Lisa E. Heuer provides a medically supervised weight loss program and has clinical expertise in the neurobiology of weight management, nutrition and exercise physiology. Her office is located at 99 Main St. in Nyack. For more information, contact Dr. Lisa Heuer at DietDoctorMD@gmail.com or 914-714-8957 or visit RocklandMedicalWeightLoss.com.