The increasing rates of obesity worldwide have sparked interest in understanding the underlying causes of overeating. One emerging concept is “food addiction,” which suggests that, for some individuals, certain foods can trigger addictive behaviors similar to those seen with substance use disorders. This article delves into the concept of food addiction, examining the evidence, diagnostic criteria, and potential interventions for overeating.
One common explanation of the increase in obesity over recent decades is the environment and, in particular, the availability of highly varied, palatable and fattening foods—which have been considered to be addictive.
Variety of palatable and fattening foods contributing to the concept of food addiction.
Exploring the DSM-5 Criteria for Food Addiction
To understand food addiction, it’s helpful to consider the diagnostic criteria for substance use disorders (SUDs) outlined in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5). These criteria include impaired control, social impairment, repeated use despite negative consequences, and physiological criteria like tolerance and withdrawal. While not all criteria perfectly translate to food, examining them in the context of eating habits provides insights.
Impaired Control Over Eating
One of the primary characteristics of addiction is a loss of control. This can manifest in several ways related to food:
- Eating larger amounts than intended: Overweight, obese, and individuals with binge eating disorder often report consuming excessive amounts of food, even when they initially intended to eat less.
- Unsuccessful efforts to restrict intake: Many people struggle to maintain diets, with long-term failure and even weight gain being common outcomes.
- Time spent obtaining, using, and recovering: Similar to substance abuse, individuals may dedicate significant time to planning binges, purchasing food, and recovering from episodes of overeating, which can be a planned behavior that requires a great deal of effort to purchase and store foods ready for a binge episode.
The Role of Impulsivity
Impulsivity, the tendency to act without thinking, plays a significant role in both substance use and overeating. Studies show that impulsivity is heightened in individuals with substance use disorders and in those who overeat or are obese. Those high in self-control have been shown to be less likely to give in to temptation and are more likely to maintain a healthy diet and engage in physical exercise.
Reward Sensitivity and Overeating
Sensitivity to reward, the degree to which someone experiences pleasure from rewarding stimuli, is another factor. A heightened general sensitivity to reward has also been linked to both substance use and overeating. Some research suggests that reward sensitivity may decrease with prolonged overeating, leading to anhedonia (a reduced ability to experience pleasure). This can lead to a cycle of seeking rewarding activities, like consuming palatable foods, as a form of self-medication.
Craving Specific Foods
Food cravings, an intense desire to consume a particular food, are a common experience. Certain foods like chocolate, carbohydrates, and salty snacks are frequently craved. The most commonly reported craved food is chocolate, although cravings for carbohydrates and salty snacks are also common.
Recurrent food cravings are of interest in relation to food addiction as they have been associated with binge eating, increased food intake and increased BMI.
- Cue-induced craving: Exposure to food cues, such as advertisements or the sight of tempting treats, can trigger cravings. This is similar to how drug-related cues can induce cravings in individuals with substance use disorders. It is possible, therefore, that certain individuals are more susceptible to cue-induced cravings, and also that this susceptibility may transfer across different substances.
Social Impairment Due to Overeating
Overeating and obesity can negatively impact social functioning, particularly among children and adolescents. Poor social functioning in overweight children may be partly due to the overt victimisation and teasing experienced as a direct result of their weight status.
- Weight stigma: Overweight individuals may experience discrimination in social and romantic settings. Weight stigmatisation may also affect interpersonal friendships and romantic relationships in adulthood with reports of discriminatory attitudes and behaviours in occupational and romantic settings.
- Quality of life: Studies show that individuals meeting the criteria for food addiction often score lower on physical, mental, and social aspects of health-related quality of life.
Continued Use Despite Negative Consequences
Despite pervasive warnings regarding the consequences of overeating, from the media, government, and the medical profession, it seems fair to assume that most overweight and obese individuals are aware of the negative outcomes associated with their dietary behavior.
The physical and psychological effects of being overweight are well-documented, including increased risk of diabetes, heart disease, and depression. Yet, many people continue to overeat despite these known risks.
Physiological Aspects: Tolerance and Withdrawal
Tolerance occurs when repeated exposure to a substance leads to a diminished effect, requiring more of the substance to achieve the same result. Withdrawal refers to the physical or psychological symptoms that occur when someone reduces or stops using a substance. There are also anecdotal reports of withdrawal-like symptoms in humans, including persistent cravings and negative affects when attempting to reduce food intake , as well as the tendency to eat to avoid the emotional symptoms associated with withdrawal such as fatigue, anxiety and depression .
- Sugar tolerance in animals: Animal studies have shown that rats given excessive sugar access increase their intake over time.
- Withdrawal symptoms: Some individuals report experiencing withdrawal-like symptoms such as cravings and negative emotions when attempting to reduce food intake.
Neurobiological Similarities Between Food and Drugs
Research has identified several neurobiological similarities between how the brain responds to palatable foods and addictive drugs.
Reward System and Dopamine
Addictive drugs and palatable foods both activate the mesolimbic dopamine system, which is central to reward processing. Animal studies have shown that, similar to drugs of abuse, palatable foods are capable of triggering dopamine release in the nucleus accumbens (NAc) and ventral tegmental area (VTA)
Inhibitory Control and Prefrontal Cortex
The prefrontal cortex, responsible for inhibitory control, shows reduced activity in individuals with obesity. Similar findings have been observed in healthy-weight participants, who demonstrated a positive correlation between dopamine receptor availability and inhibitory control performance on the stop-signal task.
It has been hypothesised that overeating is initially caused by a hyper-responsive reward circuitry and maintained by the subsequent degradation of this system
Treatment Implications for Food Addiction
Recognizing the similarities between substance addictions and overeating opens the door to new treatment approaches. Approaches that target increased impulsivity and reduced self-control may have more success.
Cognitive Interventions
Cognitive interventions aim to reduce cognitive biases associated with overeating, such as attentional biases (tendency to focus on food-related cues).
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Attentional bias modification: Training tasks can help individuals shift their attention away from tempting food cues.
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Evaluative conditioning: This technique pairs unhealthy foods with negative stimuli to reduce implicit liking.
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Response inhibition training: Training individuals to inhibit responses to food stimuli can reduce consumption.
Neuromodulation Techniques
Non-surgical brain stimulation techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), are being explored for their potential to reduce craving and addictive behaviors by altering neural activity and increasing dopamine. However, as the number of studies utilizing tDCS in the exploration of its effects on food craving has increased, evidence of efficacy has weakened.
Therapeutic Interventions
Therapeutic interventions such as Overeaters Anonymous and cognitive behavioral therapy have taken a more holistic approach to the treatment of obesity.
- Overeaters Anonymous (OA): Based on the 12-step program of Alcoholics Anonymous, OA views compulsive overeating as an addiction-like illness.
- Cognitive behavioral therapy (CBT): CBT helps individuals identify and modify maladaptive thoughts and behaviors related to eating. The focus of CBT is to replace dysfunctional eating with more normalised eating behaviour, therefore, favouring moderation and flexibility rather than absolute restraint.
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Conclusion: The Ongoing Debate of Food Addiction
While there is evidence supporting the concept of food addiction, it is unlikely to apply to the majority of cases of overeating. The term ‘food addiction’ is likely to apply only in a minority of cases. However, research investigating the underlying psychological causes of overeating within the context of food addiction has led to some novel and potentially effective interventions. Understanding the similarities and differences between the addictive characteristics of food and illicit substances should prove fruitful in further developing these interventions. The idea of “food addiction” is expected to remain hotly debated.
