Is fast food really addictive?

When Pulitzer Prize-winning investigative reporter Michael Moss was first working on his book, Salt Sugar Fat: How the Food Giants Hooked Us, he was careful to steer clear of the word addiction.

“It seemed crazy to me to compare Twinkies to heroin, you know, or even Cheetos to heroin,” he tells Sliced.

Indeed, despite the work of organizations like Overeaters Anonymous that help people with compulsive eating, binge eating disorders, and similar health problems relating to food, saying that food is addictive is often met with a raised eyebrow or two.

Unlike cocaine or cigarettes, food — even the ultraprocessed stuff — doesn’t contain addictive chemicals, which means, according to Dr. Waqas Mahmood, that it cannot be considered truly addictive.

“You will find a lot of studies on the internet about the addiction to fast food,” he says. “Many of these studies will conclude that fast food is addictive. However, one thing you will never find in these studies is scientific proof of the addiction to fast food.”

“It's the same thing that makes TV, video games, porn, and gambling addictive.”

Studies have explored the link between compulsive eating and drug addiction. A research review carried out by Andrea Garber and Robert Lustig examining the relationship between insulin resistance, obesity, and overconsumption of fast food proved inconclusive. However, they warn in their study that fast food is a “potentially addictive substance most likely to create dependence in vulnerable populations.” Other studies have linked a sweet tooth to an increased likelihood of getting hooked on amphetamines, and still others found that sugar consumption could inspire a greater reward response in the brain than cocaine. But ultimately, the absence of certain addictive compounds means that for many experts the idea of food addiction isn’t supported by evidence. 

“Fast food is not addictive unless you add addictive substances such as caffeine,” says Mahmood. “Scientific studies also don’t conform to the addiction to fast food.” But other experts continue to argue that food can demonstrate addictive qualities, in particular UPF — ultraprocessed food.

One way in which food can replicate the experience of addiction is the way it stimulates the production of the mood-boosting hormone dopamine. 

“Dopamine is both an anticipatory and a reward neurotransmitter,” explains Dr. Jason Wessel, Head of Psychology at ContemplateWeightLoss.com. “Our brains release dopamine in anticipation of (i.e., before) a reward, as well as immediately during/after we eat it. It's the anticipation, action, and reward loop that makes it addictive. Reinforced each time by the sensation/pleasure we get when eating tasty junk food.”

For many experts, it’s not the dopamine or even the blood sugar rush that makes ultraprocessed food so dangerous for us: It’s the way in which these foods intersect with nostalgia and memory.

Wessel adds that while dopamine is totally natural, certain external stimuli can further boost its production — including food.

“I think of fast food [as] an example of supernormal stimuli — an exaggerated version of something we like under normal circumstances, but when it's extreme it messes with our decision-making,” he explains. “It's the same thing that makes TV, video games, porn, and gambling addictive.”

But while dopamine definitely encourages you to consume certain foods again and again, Dr. Hector Perez, chief surgeon of Bariatric Journal, says dopamine itself is not addictive.

“You can't be addicted to dopamine — but you can become addicted to activities that release it,” he explains. “It's the craving that causes the addiction, not the dopamine itself. The strong craving for the pleasure associated with the activity can lead to compulsive behaviour, even when it's harmful.”

Dr. Daniel Boyer of the Farr Institute cites another chemical affected by the consumption of ultraprocessed food: leptin. Leptin is a hormone that controls appetite, and the consumption of ultraprocessed foods can increase resistance to it, all the while inducing the production of more ghrelin, a hormone that triggers hunger pangs and cravings. The unnatural presence of these two natural hormones can promote unhealthy eating.

The effect of food on blood sugar can also create an addiction-like quality, according to Dr. Brian Kaplan, MD. “The main source of addiction is sugar and flavour enhancers,” he says, noting that eating sugar raises blood sugar, which causes the body to release insulin to balance things out once more. Too much sugar causes the body to “overreact,” he explains, producing too much insulin.

“The food becomes addictive because you remember how good it made you feel in the past.”

“This insulin spike causes the blood sugar to go — not to normal — but to a lower than normal level,” he explains. “The body now registers that the blood sugar is too low and triggers a craving for sugar. If we give in to that craving and eat something sweet, we are back at stage one and the cycle repeats itself. And all the sugar that is transferred into the tissues by the insulin spike, leads to fat production and possible obesity.”

The cycle, he says, can also lead to fatigue, moodiness, and even depression. One study on rats described food addiction as a “plausible” consequence, given the neurochemical changes that occur in the brain after consuming too much sugar — or other foods that, Boyer says, are essentially “turned into sugar in the blood” like pasta, white bread, white rice, and potatoes.

The physiological aspect of food addiction is just the tip of the iceberg, however. For many experts, it’s not the dopamine or even the blood sugar rush that makes ultraprocessed food so dangerous for us: It’s the way in which these foods intersect with nostalgia and memory.

“That’s why Coca-Cola has spent so much energy trying to get soda in the hands of kids when they go to the ballpark with their parents,” explains Moss. “Because that’s such a powerful emotional experience that these kids will then kind of retain for the rest of their life, and when they want to feel joy or comfort, they’ll think of that soda.”

Perez agrees.

“The food becomes addictive because you remember how good it made you feel in the past,” he says, “and you want to experience that feeling again. And if you're not feeling the same level of pleasure from the same amount of food, you may keep eating more and more to try to reach that level.”

For Isla Zyair, nutritionist, blogger, and expert on plant-based nutrition at Obesity Controllers Association, fast food chains and processed food companies also tap into other ways in which these foods can be attractive to us psychologically.

“[T]he chemical reactions caused by these four ingredients in the brain are almost identical to those that occur when you take drugs like heroin or cocaine in the brain’s reward system.”

“Many fast food restaurants use strategies like smells and bright lights to lure customers in and encourage them to eat more,” she says. Perez suggests the relatively low prices of processed food makes it even harder to resist.

“This convenience makes it more likely that people will turn to fast food when they're feeling hungry, even if they know it's not the best choice for their health,” he says. 

“I think there is a lot to be said for the convenience,” agrees Wessel. “For example, driving past a restaurant or seeing a sign can be enough to trigger dopamine.”

And good emotions aren’t the only ones that matter. Sarah Glinski, RD, cites one study on rodents that, following a period of restriction, gave the animals access to foods high in fat and sugar.

“In other words, restriction led to bingeing,” she says. “This is a well-known phenomenon, and it begs the question — if we don’t see fast food as ‘bad’ and restrict it, will we really be addicted to it? Or will we just binge in response to restriction?”

Wessel echoes this, saying that self-esteem issues or body-image issues “can also lead to negative spirals where the consumption might satisfy a dopaminergic impulse, but lead to additional distress, creating a craving for comfort that also triggers a craving for junk food.”

It’s also easy to overlook the idea that ultraprocessed food is actually engineered to be addictive; after all, it’s designed to be delicious.

“The main ingredients common in fast food are refined carbs, fat, sugar, and salt, making fast food highly palatable,” notes Boyer. “These four ingredients are at a high-level in fast food and can hijack your brain’s reward system and cause cravings that are hard to ignore.”

“[T]he chemical reactions caused by these four ingredients in the brain are almost identical to those that occur when you take drugs like heroin or cocaine in the brain’s reward system.”

For Wendy Lord, who is a registered dietitian and consultant for Sensible Digs, the marriage of sugar, salt, and fat in most processed foods leads to a “bliss point” which makes it uniquely irresistible.

“Research has shown that we have an on-off switch when it comes to eating foods that contain high amounts of sugar or fat on their own,” she says. “But when you combine sugar with fat in foods such as chocolate or cheesecake, your taste buds and the pleasure centres in your brain light up, dulling down the normal mechanisms that would tell you to stop eating.”

“[While fast foods are not addictive in the true sense of the word, they trick your body into wanting more … and more …  and more!”

Moss recognizes this as well. He cites a study which proved that adding sugar to fat seemed to mess with people’s impulses. He also cites researcher Dana Small who notes that the combination of sugar and fat is hard to find in nature.

“The food industry discovered that by combining the two into a Milky Way bar or a milkshake,” explains Moss, “they were creating something that, through the engineering, caused people to be much less able to have control.”

But while companies engineer things to be tasty, Moss says there isn’t a big conspiracy to unpack.

“I looked for smoking guns like that,” he says, noting that when Philip Morris owned Kraft, the company conducted its own research to understand its vulnerability to lawsuits similar to those which cigarette companies had faced.

Despite the clear links between consumption of ultraprocessed foods and a lack or loss of control, using the word addiction to describe this relationship remains problematic for many experts.

“I have confidence that the people at Kraft wanted to find those documents, because they were pushing from inside to sort of change the company,” Moss says. “[T]hey never found something, I think, that would convince a jury to convict PepsiCo for making Cheetos so outrageously attractive that they were in fact addictive.”

The reality, he says, is far less nefarious: Companies are merely “using our own basic instincts against us.” 

“They’ve come up with all of these really high-caloric, empty junk food snacks. Because we get excited by the calories, and we don’t really have any tools — instinctive, basic, biological tools — that can help us distinguish between junk calories and the healthy calories.”

Despite the clear links between consumption of ultraprocessed foods and a lack or loss of control, using the word addiction to describe this relationship remains problematic for many experts.

“[W]hile addiction doesn't always have to include tolerance and dependence, they're pretty key signs, and not often present in the case of junk food addiction to the degree that they're present in drug or alcohol addiction,” says Wessel.

“While it's unlikely that anyone is physically addicted to fast food in the same way they might be addicted to drugs or alcohol,” adds Zyair, “it's clear that it can be challenging to resist its siren call.”

The good news is that since fast food might not be addictive in a traditional sense, it may be easier to kick those cravings.

“When you stop eating fast food and replace it with healthier options,” Lord says, “your body stops craving them fairly quickly.”