X-PERT Blog: Can we be addicted to food?
Matt Whitaker – Researcher and Trainer in Public Health
The word addiction can be defined as being physically and/or mentally dependant on a particular substance. Notorious substances that can infamously cause addictions include: gambling, alcohol, drugs, sex and smoking. One arguably controversial substance that many add to this list is food. There is a compelling argument for this that spams over psychological, behavioural and biological grounds. This blog will summarise our thoughts on whether this argument justifies the notion that we, as humans can become addicted to food.
Drug addiction can be clinically diagnosed following consultations with psychologists, psychiatrists and specialist councillors. No such clinical system exists for food addiction, making it more challenging to confidently diagnose. Food addiction is still measured however, using: self-report questionnaires; patient self-identification and the Yale Food Addiction Scale, which is based on a criteria for substance use disorder. This means of measurements suggest that 11.1% of healthy-weight individuals show signs of food addiction, whereas 24.9% of overweight/obese individuals do.
When food addiction is reviewed in research, variables that are examined are in line with substance abuse, including: neurobiological changes, preoccupation with the food, diminished control, social impairments, risky use, tolerance/withdrawal and relapse.
Clearly there are similarities between food and substance addiction when it comes to measuring and reviewing. These similarities carry over when one considers the underlying biology behind the addiction pathway, which largely involves the neurotransmitter dopamine. Dopamine is responsible for the creation of habits, whether they be ‘good’ or ‘bad’. Substances/activities that we enjoy release dopamine. This dopamine release essentially tells us how good they are going to be and drives the want to do them. This leads to cravings and ultimately may lead to the creation of a habit. If continued over a period of time this habit may be reinforcement to the point is becomes an addiction.
Research suggests this dopamine response is directly linked to the intake of some foods. This means the process of eating some foods is comparable to drug use when considering both biological and behavioural aspects such as dopamine expression, cravings and relapse to previously restricted foods. Some researchers argue that there is a significant overlap between food addiction and substance abuse, although it is commonly concluded that more research is needed.
The types of foods that elicit this response are the hyper-palatable, ultra-processed foods. When fats and carbs are combined with the absence of protein and fibre the food offers huge amounts of energy with very little satiety. These foods are typically far more craved and overconsumed compared to foods natural high in fat or carbs. The cravings carry over into perceived value where research has suggested that people are happier to spend more money on these ultra-processed foods.
This is taken one step further in animal studies where it has been shown that when animals are given a highly processed food, such as milk chocolate in a certain room/area they are more likely to spend time in this area. Some studies have even shown that despite punishment (including physical pain) following consumption, animals still sought consumption of the hyper-palatable foods. When measured, their dopamine response was enhanced, following a similar pattern to that seen in substance abuse. Additionally, if supply of these foods was cut off the animals showed several signs of anxiety, similar to those seen when one stops taking recreational drugs.
So, one of the factors that lead to this overeating is the sense of reward given by a heightened release of dopamine. It has been suggested that those who meet the criteria for food addiction have an amplified release of dopamine in response to eating. Plus, appetite suppressant that blocks dopamine was not effectively functioning in those who scored positively for food addiction. It has been suggested that some may actually build up a resistance to this dopamine due to the chronic exposure but more research is needed to firm this hypothesis.
Some researchers argue that food cannot be ‘addictive’ as it is essential for survival, yet others point out the similarities with drug addiction with biological (brain reward), behavioural (eating more than intended, relapse following restriction) and psychological (cravings and impaired control with consumption) means.
Research that is against the notion of food addiction is often sponsored by industry (that would lose out if food addiction was deemed to be clinically factual), which may question their conclusions. When examined in isolation these processed foods/drinks have been shown to release a neurological response in line with that seen in addictive drugs.
So can we be addicted to food? We suggest yes, although more research is needed to confirm this opinion as is guidelines on clinical diagnosis.
Any questions, feedback and/or suggestions would be most welcomed, as is any request for the research supporting this blog. Please email me at Matthew.Whitaker@xperthealth.org.uk