The latest edition of the Diagnostic and Statistical Manual (DSM), a handbook used by healthcare professionals to diagnose mental illnesses, featured several new disorders. One was Gambling Disorder, the first and only behavioural addiction currently included in the manual. It was included on the basis that gambling activates the same parts of the brain as drugs like cocaine (specifically, parts of the brain related to reward and motivation). However, calls from the scientific community to recognise overeating as an addictive disorder were not applied, sparking controversy and debate amongst researchers.
The idea of food being addictive is not a new one. In 1890, the word “addiction” was first used scientifically in one of the earliest medical journals on this topic (The Journal of Inebriety), in reference to chocolate. The term “food addiction” was later coined by Theron Randolph in 1956 but remained fairly unexplored in the following years. However, driven by rising rates of obesity and concern over the associated health and economic costs, the last decade has seen a rapid increase in interest in food addiction amongst scientists, the media and the public.
As a relatively young field of research, many questions about food addiction remain unanswered: Can overeating become an uncontrollable medical condition? Is there enough evidence to include it as a mental disorder in the DSM? And if so, what are the potential consequences of such an important decision?
What is the evidence for Food Addiction?
Addiction?
“My drug of choice is food. I use food for the same reasons an addict uses drugs: to comfort, to soothe, to ease stress.” — Oprah Winfrey
To be diagnosed with an addictive disorder you must meet the following criteria:
i) impaired control — difficulty controlling your use of the substance, ii) social impairment — experiencing social problems due to the addiction, iii) risky use — continuing to use the substance despite physical or mental health problems (or both),and iv) pharmacological criteria — such as withdrawal symptoms (symptoms like sweating or shaking as a result of stopping opioids suddenly).
These have been shown in animal models in relation to foods high in fat or sugar. One study found that rats were willing to tolerate painful foot shocks to acquire a supply of Oreo cookies, which was interpreted as evidence of risky use. Other studies have documented intense withdrawal symptoms, such as teeth chattering, head shaking, anxiety and aggression shortly after a diet high in sugar was removed.
In humans, the evidence is less clear. There is plenty of evidence from online forums and clinical case studies showing signs of craving, lack of control and withdrawal in people trying to cut down on processed food such as bread, sweets and crisps. But this type of evidence can be subjective and is often based on small numbers of participants. Scientists need much more than this to prove that food addiction exists.
“Over the years, I needed to consume more calories for longer periods to achieve the same sense of control, emotional numbness, and euphoria” — Hansen (2016)
More recently, scientists have shown that the same brain areas are activated by drugs like alcohol, cocaine, heroin and by processed foods. These are brain areas involved in reward, motivation, stress and self-control. Of course, we expect some overlap in brain areas relevant to both food and pleasure, but there is more and more evidence suggesting that they share brain processes which, when hijacked, result in binging and loss of control.
One such brain imaging study found that individuals who tend to score higher on a specific scale that measures “food addiction” (for example, that eat to the point of feeling physical ill or that avoid professional or social situations where certain foods are available for fear of overeating) have increased activity in reward and motivation parts of the brain when they were told to expect a chocolate milkshake, and decreased activity in self-control parts of the brain when actually given the chocolate milkshake to drink. Interestingly, this can be found in both people of normal weight and with obesity.
So if evidence shows that processed food activates the same reward and motivational parts of the brain as drugs and gambling do, why has food addiction not been officially recognised yet?
Critics of food addiction argue that food is necessary for survival and therefore cannot be addictive. But think for a moment about water, a substance that is essential for survival. Water can become addictive when certain ingredients are added. Beer, for example, can be up to 97% water but becomes an addictive substance when ethanol is added.
Supporters of the notion that food addiction does exist are not arguing that foods such as vegetables are addictive. It is the refined ingredients such as sugar and fats, specifically added to processed food, that make the food addictive.
A recent BBC documentary “Why are we getting so fat?” featuring Dr Giles Yeo, a geneticist from Cambridge University, emphasises the importance of studying combinations of nutrients that do not occur naturally, but when combined can “pack a punch” to brain motivation circuits and change our normal eating behaviour.
Yeo quotes a study where food items that containedbothfat and carbohydrate were valued more highly than food items high in just fat or carbohydrate alone. These “double-whammy” food items also had a greater effect on brain reward areas than the food items that were high in just fat or carbohydrate alone.
It might seem obvious to some people that foods high in carbohydrates and fat would be more addictive, but as a recent Guardian article noted there is a certain hysteria surrounding food in today’s mainstream media. On a daily basis, we are bombarded with contradictory advice about what to eat and what not to eat. It is no wonder than many of us feel alienated and confused.
A task for future research will be to work out exactly which combinations of nutrients have the potential to become addictive and to communicate this in a clear way to the public.
What would be the potential repercussions of including food addiction in the DSM?
Classifying overeating as an addiction would have far-reaching effects. It will undoubtedly impact public health, healthcare provision, economics, public opinion and governmental policy.
Valuable lessons can be learned from looking back at the history of the tobacco industry. For many years the tobacco industry framed smoking addiction as a problem of self-control, blaming individuals rather than the companies supplying the cigarettes.
Person-centered treatments, where the individual addicted to smoking was helped in finding their way of reducing or stopping, were the only accepted approach for a long time. This was before any effective policy interventions were considered due to lobbying from smoking companies.
Luckily, things have changed now. Smoking rates in the UK are at an all-time low because of population-level changes to taxation, shop displays and laws on smoking indoors.
Currently, much of society blames individuals with obesity for their excess weight, with common misunderstandings that individuals with obesity are entirely responsible for their condition. This mirrors what happened to smokers 50 years ago.
These views are prevalent and exist even in those making critical decisions for the health of the UK. In a recent speech Health Secretary, Matt Hancock, said the following:
“Prevention is about ensuring that people take greater responsibility for managing their own health. It’s about people choosing to look after themselves better…making better choices by limiting alcohol, sugar, salt and fat.”
However, if the concept of food addiction is given support, we may see a shift towards more balanced, society-wide approaches to tackling the population’s diet. We have to make it easier for people to make healthy choices, across all social classes. Ideally, the price of processed foods should increase, the price of fresh, healthy produce should be subsidised, and advertising should be regulated more.
Moreover, we could hope to see a reduction in weight-related discrimination targeted at individuals who are overweight or living with obesity, which would actually have positive consequences not only for their mental health, but also for their weight loss and maintenance of weight loss over time.
However, not everybody shares this view.
Opposing researchers theorise that it could offer individuals an excuse for unhealthy eating patterns and worsen the problem of obesity. Also, we could see the food industry try to contest research or block policy reforms, as has already occurred in the US with regard to menu labeling and restriction of junk food in schools. The food industry may also begin more aggressive marketing in developing countries, where laws are more relaxed (a trend we are already beginning to see).
This issue will continue to be debated. As the field of food addiction moves into unknown territory, it important to truly understand if advocating a diagnosis of “food addiction” will have a more harmful or more beneficial net impact on health.
Research, and more evidence, are urgently needed. The decision about this important question should not be left to the strongest lobbiers, it should be based on the populations’ health and wellbeing. We will need to work with the government and food producers to achieve this.