Carolina Cawthon, a PhD student in Foods and Nutrition department at the University of Georgia, recently gave a seminar on food addiction. Ms. Cawthon’s talk shed some light on the debate about whether or not food addiction is an actual addiction. During her talk, she covered how our brains make decisions about food, what addiction is, and the evidence we have concerning the addictive capabilities of foods in animals and humans. Understanding food addiction is important area in the arena of public health because it is a topic that is impacted by the design of our food system and the availability of “addictive” foods, as well as policy surrounding taxation of such foods.
Our food intake is regulated by many things, including stretch receptors in our stomachs (sense the amount of food that is being taken in) and hormones (send signals to our brains about hunger and fullness). The decision-making portion of our brain, which decides to eat or not eat a food, is influenced by both reasoning and reward areas of the brain. The reasoning areas operate by objectively analyzing how much we have eaten already and how hungry or full we feel. The reward areas of the brain send messages related to anticipation of how good it will feel to eat something.
Addiction is an illness in which an individual is dependent on a substance and seeks it out to avoid distress (withdrawals, anxiety, etc.). The individual continues to use the substance in spite of consequences and has a high level of motivation to obtain the substance. Use of the substance becomes a compulsion. In the physiologic state of dependence on a substance (like drugs or alcohol), the individual’s body adapts so that they need more of the substance to achieve the desired effects.
Scientists have used rats to study addiction related to food and drugs. They have found that rats become addicted to substances at rates comparable to humans and thus are useful in addiction studies. Researchers have found that rats with more impulsive traits are more likely to demonstrate addicted behaviors in relation to food intake, especially when offered a diet high in fat and sugar.
The Yale Food Addiction Scale is a tool used to measure food addiction traits in human subjects. Brain imaging data has revealed that individuals with higher scores using this scale (indicating food addiction) have higher anticipation for food and lower reward after receiving the anticipated food. This aligns with the classic attributes of addiction- heightened desire for a substance but lower satisfaction after receiving it. Researchers have used this scale to identify individuals with a greater risk for food addiction to be: women, overweight or obese, over 35 years of age, and with a previous history of disordered eating. Dopamine is a neurotransmitter involved in the brain’s reward system. Some research has shown that individuals with higher BMIs have lower densities of dopamine receptors, which support hypothesis overweight or obese individuals could feel less rewarded by food and thus eat more to compensate. So we have some data that points to the addictive capabilities of food. However, a complicating factor is that while alcohol and drug addicts can be advised to stop using the substances completely, people need food to live and thus could never be advised to stop eating.
Even though great strides are being made in food addiction research, it is not entirely clear whether food addiction is the same type of illness as drug or alcohol addiction. There is no consensus among professionals about the validity of food addiction yet. Given the rise of obesity in our nation and the detriment it is to health, a better understanding of food addiction and its characteristics will continue to be important to the success of public health efforts.