Ancient Cravings in a World of New Foods

Around 97% of us have had some form of food craving in our lifetime. But our cravings are far from random preferences - and the food industry knows it.

Why did Burger King once serve Whoppers with extra pickles, ice cream, and mustard? Why was Napoleon obsessed with liquorice? Why did I finish a week's worth of salt and vinegar chips in one sitting? Interestingly, the answers might lie deep in the biological drivers that shaped early human life.

The brain behind cravings

Cravings for food (among other things) originate in the brain, specifically within regions such as the hypothalamus, insula, and amygdala.^1,2 These areas are particularly important as they are associated with memory, emotion, and reward. When you start to crave a particular food, your brain is reflecting a heightened state of reward anticipation, often intertwined with emotional needs and memories. You could think of it as if your brain is creating a mental itch, then letting you know just how good it will feel to scratch it. 

On a chemical level, there is a complex process occurring, with neurotransmitters like dopamine playing a crucial role by signalling pleasure and reward that drive us to fulfil that craving. This process is then further influenced by factors that affect brain activity, such as stress, sleep patterns, exercise habits, hormonal changes, and even certain medications.¹ With all this going on behind the scenes of an everyday craving, it's tough to understand exactly why certain foods are appealing at certain times. But, there are some common patterns in the types of food we crave and they explain a lot about where cravings truly originated.

Ancient origins

Have you ever noticed that you’re more likely to crave something calorie-dense, usually sugary or fatty, rather than a healthy, balanced meal? Despite culture and personal circumstance certainly playing a role in the specific foods we crave, the roots behind our hankerings are largely the same.⁷

Our ancestors lived in harsh and often unpredictable conditions, so we evolved to prefer energy-rich foods - much like many wild animals do. We are programmed, through evolution, to favour immediate benefits, like energy intake, over long-term health. In a world before supermarkets, this made a lot of sense. We needed to seek out energy-rich food to survive and reproduce.³ So, the brain's inclination towards sugars and fats was beneficial when such foods were rare. However, in today's world, where energy-dense foods are abundant and easily accessible through supermarkets, fast food chains, and online delivery, this innate preference poses a significant health challenge. And things got even more complicated when ultra-processed foods hit the market. 

How ultra-processed foods press our craving buttons 

Ultra-processed foods (UPFs) still don’t have a universally agreed definition. They are typically highly engineered food products containing substances derived from food and additives rather than intact, minimally processed foods.⁵ They often rely on preservatives, sweeteners, and additives for their texture and taste. 

But ultra-processed foods aren’t just the obvious sweet treats and reconstituted hams. UPF expert Chris Van Tulleken explains in his 2023 Ted Talk: “Ultra-processed foods are foods that contain at least one ingredient that you wouldn’t find in a normal kitchen.” Importantly, UPFs are created and marketed with the aim of making a profit. And though research about UPF is still in the early stages, it seems like consuming it in excess is linked to a wide range of health problems, including obesity, overall cancer risk as well as specific cancers such as ovarian, anxiety disorders, liver disease, Irritable Bowel Syndrome (IBS), and cardiovascular disease.

What you need to know about ultra-processed foods

In order to turn a profit, ultra-processed foods are purposefully and skillfully designed to tap into our evolutionary inclinations. These products often have elevated levels of sugar, salt, and unhealthy fats, which provide instant gratification and trigger the brain's biological reward systems.⁴  

Manufacturers invest substantial resources in optimising the "bliss point" of foods - that perfect combination of sweetness, saltiness, and fattiness that maximise our pleasure and entices repeated consumption. Studies have even shown that eating these “hyperpalatable foods” too often might interfere with how the brain processes these hormonal signals, to the point where we will continue to have cravings despite having eaten more than enough food.¹ And even when we try to make healthier choices, it’s not always easy to know what’s hiding in our favourite UPF. Subway’s bread, for example, has so much added sugar that it's considered a ‘cake’ for tax purposes in Ireland.⁶ 

When you consider the money and science behind UPF, along with their often low prices and convenience for time-strapped individuals, it's no wonder we often find ourselves drawn to these foods. This attraction can range from just a persistent desire (a craving) to something more serious like addiction, where we not only experience intense cravings but also lose control over our eating behaviours entirely. 

Governments and regulatory bodies don't have to stand by passively in the face of this issue. Some countries are already taking strong measures to curb the influence of UPFs, aiming to strike a balance between consumer choice and public health. For instance, Mexico has implemented significant policy changes, including not only mandatory health warnings on labels but also banning cartoon characters from cereal boxes aimed at children.¹⁵

Overfed and undernourished

Alongside the proliferation of ultra-processed foods, many people consume what are termed "empty calories." These calories, typically derived from sugars, unhealthy fats, and refined grains, contribute to energy intake but offer minimal nutritional value. As a result, an increasing number of individuals around the world are exceeding their daily caloric requirements without obtaining the necessary vitamins, minerals, fibres, and other beneficial compounds.⁸ A 2018 review in the International Journal of Obesity highlighted the impact of this on the global obesity crisis, showing that while individuals living with obesity had high caloric intakes, they often displayed deficiencies in crucial vitamins and minerals.⁹ 

Learn why producing more food doesn’t mean less hunger

It is widely assumed that when our diet lacks these vital nutrients, the body may generate cravings as a plea for these missing components. The idea is that our body knows something is wrong, but your reward pathways aren’t always as fine-tuned as they need to be. So your body, in search of essential vitamins and minerals, can send you back to eating tasty but nutritionally void food. While this assumption is plausible, the evidence doesn’t fully support this widely held theory. It’s true that a balanced diet can help reduce long-term cravings, but feeling compelled to eat certain foods may also be a learned behaviour - which can also be “unlearned” with the right support. For instance, you could swap your usual evening snack for different activity like listening to an audiobook or some music.⁷ 

Is sugar a drug?

You have probably heard at least one comparison between sugar and a controlled drug - from claims that ‘X’ grams of sugar is worse than a cigarette to the idea that sugar addiction is as strong as cocaine addiction. But is there really any basis for these claims?

The theory goes that when you consume sugar, your brain releases dopamine, a neurotransmitter and complex hormone associated with the pleasure and reward centre of the brain. This release of dopamine is what makes sugary foods feel so rewarding. Over time, with repeated exposure to high levels of sugar, the brain may come to rely on sugar to release dopamine, much in the way it does with certain drugs - cocaine being perhaps the most similar one, as its use also releases a sudden burst of dopamine.¹⁰ While this theory is founded on older animal-based studies, it presents some interesting insights into how sugar is used to hack our reward pathways.^{9,10, 11}

Keep in mind that the sugar-drug comparison isn't as straightforward as these studies may imply. For one, humans aren't rats, and while animal studies provide valuable insights, they don't always translate directly to human behaviour. Additionally, while drugs like cocaine have direct, powerful effects on the brain's reward centre and can lead to harmful, compulsive behaviour, the relationship with sugar is more nuanced. People can enjoy sugary treats occasionally without spiralling into a cycle of addiction. 

While our brain does see sugar as a ‘reward’ in similar ways to how it sees some drugs, and overconsumption is linked to various health issues, calling sugar as addictive as cocaine is likely an oversimplification and remains debated. Still, the broader message remains clear: limiting excessive sugar intake is beneficial for overall health.

Pregnancy cravings - myth or reality?

Before we pack up, let’s address one last topic. Pregnancy cravings, intense desires for specific foods during gestation, have become a cultural touchstone, with some companies even cashing in. Take Burger King, which ran campaigns targeting expectant parents with quirky combos like currywurst burgers topped with fried herring.¹⁶ But are they a genuine physiological phenomenon or merely a myth?

During pregnancy, a woman's body undergoes a myriad of hormonal changes. For example, elevated levels of human chorionic gonadotropin (hCG), progesterone, and oestrogen can alter a woman's sense of taste and smell.¹² These changes in senses combined with the physical demands of pregnancy can lead to an increased appetite for certain foods or aversions to others.

Studies have found that the nature of pregnancy cravings can vary based on cultural and societal influences, but certain trends do emerge. For example, a study published in Frontiers in Psychology found that sweet foods, including fruits and sweets, are among the most commonly craved foods during pregnancy. Alongside sweet cravings, many women also report strong desires for savoury foods, such as salty snacks, spicy foods, and protein-rich meats. Conversely, many pregnant women also report aversions to foods, often those with strong smells or flavours.¹⁴

While many pregnancy cravings are benign, some can pose risks. A condition called ‘pica’ involves craving and consuming non-food items, such as dirt, clay, or hair. It is significantly less common than normal cravings, but due to its nature, it can pose extreme risks.¹³ Pica can be harmful to both the mother and unborn child, and is thought to be linked to mineral deficiencies. Pregnant women should always consult with healthcare professionals about any unusual cravings, both to prevent ingesting potentially harmful items and to ensure they are healthy from a nutritional standpoint.

Curbing the cravings

Cravings, whether brought about by evolutionary predispositions, biological changes during pregnancy, or the masterful engineering of ultra-processed foods, are deeply interwoven with our neurobiology, history, and the current food environment. Today, amidst the abundance of easily accessible energy-dense foods, we are faced with a dichotomy. Our brain's ancient wiring drives us towards foods that were once vital for survival, yet in our current context, these foods contribute to a myriad of health challenges.

By equipping ourselves with knowledge and understanding, we can strive for a balanced diet that truly nourishes, not just overfeeds. We can retrain our brains to find pleasure in activities beyond indulgence. This could involve replacing mindless snacking with other dopamine-inducing activities, from walks in nature to dancing to our favourite music. We can ensure we have healthy snacks on hand that still satisfy our cravings, such as nuts and seeds (with dry-roasted peanuts a personal favourite).

But we can’t do it alone. We need policy on our side, like the decision in Mexico to remove cartoons from ultra-processed foods aimed at marketing to children. It won’t always be easy to choose the healthiest option, and you don’t have to renounce all junk food for life, but every time you choose whole, homemade meals, you are taking  a step towards better health and away from an industry that profits from our evolutionary weaknesses.