Highly Processed Foods 'as Addictive' as Tobacco

Becky McCall

November 25, 2022

LONDON — Highly processed foods meet the same criteria as tobacco for addiction, and labeling them as such might benefit public health, according to a new US study that proposes a set of criteria to assess the addictive potential of some foods.

The research suggests that healthcare professionals are taking steps towards framing food addiction as a clinical entity in its own right; it currently lacks validated treatment protocols and recognition as a clinical diagnosis.

Meanwhile, other data, reported by researchers last week at the Diabetes Professional Care (DPC) 2022 conference in London, UK, also add support to the clinical recognition of food addiction.

Clinical psychologist Jen Unwin, PhD, from Southport, UK, showed that a 3-month online program of low carbohydrate diet together with psychoeducational support significantly reduced food addiction symptoms among a varied group of individuals, not all of whom were overweight or had obesity.

Unwin said her new data represent the first widescale clinical audit of its kind, other than a prior report of three patients with food addiction who were successfully treated with a ketogenic diet. 

"Food addiction explains so much of what we see in clinical practice, where intelligent people understand what we tell them about the physiology associated with a low-carb diet, and they follow it for a while, but then they relapse," said Unwin, explaining the difficulties faced by around 20% of her patients who are considered to have food addiction.

Meanwhile, the authors of the US study, led by Ashley N. Gearhardt, PhD, a psychologist from the University of Michigan, Ann Arbor, write that the ability of highly processed foods (HPFs) "to rapidly deliver high doses of refined carbohydrates and/or fat appear key to their addictive potential. Thus, we conclude that HPFs can be considered addictive substances based on scientifically established criteria."

They assert that the contribution to preventable deaths by a diet dominated by highly processed foods is comparable to that of tobacco products, and as such, like Unwin, the authors seek clinical recognition and a more formalized protocol to manage food addiction.

"Understanding whether addiction contributes to HPF intake may lead to new treatments, as preliminary research finds that behavioral and pharmacological interventions that target addictive mechanisms may reduce compulsive HPF intake," they state

The study led by Gearhardt was published this month in the journal Addiction, and the study led by Unwin was also recently published in Frontiers in Psychiatry.

Addiction Criteria Similar to Tobacco

HPFs can be associated with an eating phenotype "that reflects the hallmarks of addiction," say Gearhardt and co-authors; typically, loss of control over intake, intense cravings, inability to cut down, and continued use despite negative consequences.

Acknowledging the lack of a single addictive agent, they explain that food addiction reflects mechanisms implicated in other addictive disorders such as smoking.

As such, in their study, Gearhardt and colleagues propose a set of scientifically based criteria for the evaluation of whether certain foods are addictive. "Specifically, we propose the primary criteria used to resolve one of the last major controversies over whether a substance, tobacco products, was addictive."

They consider certain foods according to the primary criteria that have stood the test of time after being proposed in 1988 by the US Surgeon General to establish the addictive potential of tobacco: (1) they trigger compulsive use, (2) they have psychoactive effects, and (3) they are reinforcing.

They have updated these criteria to include the ability to trigger urges and cravings, and add that "both these products [tobacco and HPFs] are legal, easily accessible, inexpensive, lack an intoxication syndrome, and are major causes of preventable death."

For example, with compulsive use, tobacco meets this criterion because evidence suggests that most smokers would like to quit but are unable to do so.

Likewise, write Gearhardt and colleagues, even "in the face of significant diet-related health consequences (eg, diabetes and cardiovascular disease), the majority of patients are unable to adhere to medically recommended dietary plans that require a reduction in HPF intake."

Reinforcement, through tobacco use, is demonstrated by its 'being sufficiently rewarding to maintain self-administration" due to its ability to deliver nicotine, they say, quoting the Surgeon General's report, and likewise, with food addiction, "both adults and children will self-administer HPFs (eg, potato chips, candy, and cookies) even when satiated."

Online Group Food Addiction Intervention Study

Unwin and co-authors want people with food addiction to be able to access a validated treatment protocol. Their study aimed to evaluate an online group intervention across multiple sites in the United States, Canada, and the UK, involving an abstinent, low-carbohydrate diet and biopsychosocial education focused on addiction and recovery in people self-identifying as having food addiction.

"Lots of people with food addiction go to GPs who don't clinically recognize this, or if they attend addiction services and psychiatry, then they tend to only specialize in drugs, alcohol, and gambling. Eating disorder services are linked but their programs mostly don't work for a food addict," Unwin remarked in an interview with Medscape Medical News.

"We feel running groups, as well as training professionals to run groups, is the best way to manage food addiction," she said, reflecting on the scale of the problem, with around 10% of adults in the UK general population considered to have food addiction. In Unwin's study, some people had type 2 diabetes and some overweight/obesity, but she added that some participants were underweight or of normal weight.

Initially, the 103 participants received weekly group (8-24 people) sessions for 10-14 weeks, and then monthly maintenance comprising follow-up that involved coaching participants on how to cope with relapse and get back on track.

Food addiction symptoms were assessed pre- and post-program using the modified Yale Food Addiction Scale (mYFAS) 2.0; ICD-10 symptoms of food-related substance use disorder (CRAVED); and mental health well-being measured using the short version of the Warwick Edinburgh Mental Wellbeing scale and body weight.

"The program eliminates processed foods with a personalized, abstinence food plan that involves education around mechanisms involved," said Unwin, who explained that processed foods deliver a dopamine high, and in response to this, the brain lowers the number of dopamine receptors to effectively counteract the increase in dopamine. This drop in dopamine receptors explains the depression often associated with food addiction.

Unwin reported that food addiction symptoms were significantly reduced, with the mYFAS dropping by 1.52, the CRAVED score by 1.53, and body weight by 2.34 kg (5.2 lb). Mental health, as measured by the Warwick Edinburgh Mental Wellbeing scale, improved by 2.37 points.

"We were very interested in mental health and well-being because it impacts so much across our lives, and we saw significant improvements here, but we were less interested in weight because food addicts come in all shapes and sizes with some people underweight," remarked Unwin. "Food addiction symptoms were significantly improved in the group, but we now need to look at the longer-term outcomes."

Unwin runs a low-carbohydrate program for type 2 diabetes with her husband David Unwin, MD, who is a GP in Southport, UK. She said that they ask patients if they think they have food addiction, and most say they do.

"I always try to explain to patients about the dopamine high, and how this starts the craving which makes people wonder when and where they can find the next sugar hit. Just thinking about the next chocolate bar gets the dopamine running for many people, and the more they tread this path then the worse it gets because the dopamine receptors keep reducing."

Lorraine Avery, RN, a diabetes nurse specialist for Solent NHS Trust, UK, who attended the DPC conference, welcomed Unwin's presentation.

"My concern as a diabetes nurse specialist is that I'm unsure all our patients recognize their food addiction, and there are often more drivers to eating than just the food in front of them," she told Medscape Medical News. "I think there's an emotional element, too. These people are often 'yo-yo' dieters, and they join lots of expert companies to help them lose weight, but these companies want them to regain and re-join their programs," she said.

"I think there is something about helping patients recognize they have a food addiction and they need to consider that other approaches might be helpful."

Addiction. Published online November 9, 2022. Full text

Front Psychiatry. Published online September 28, 2022. Full text

Unwin has reported no relevant financial relationships; some other authors have fee-paying clients with food addiction. Gearhardt and Avery have reported no relevant financial relationships.

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