The Allure of Junk Food: Unraveling Why It Captivates Consumers

Published28. October 2025, 10:00

Food: Why is junk food so good?

Healthy food is often less desirable than junk food. This is due to a combination of particular nutrients.

No, I don’t have to finish this bag of chips, but I do it anyway. This formidable mixture of carbohydrates and salt, flanked by attractive packaging, is sometimes enough to overcome our fragile discipline. Can science help us see things more clearly?

What influences our food choices?

Many factors come into play: taste, smell and consistency of course, but also hunger and the feeling of satiety, nutritional needs, emotional state – notably stress, boredom or the desire to celebrate –, the price and availability of products, habits acquired in childhood or as an adult, culture and sometimes ideological or identity choices. We must also take into account our knowledge, advertising and prevention messages.

Why does junk food win so often?

It often combines sugars, fats and salt. These nutrients activate receptors in our mouth and intestines that trigger pleasant sensations. The brain’s reward circuitry is activated and releases dopamine, which reinforces the urge to return to that type of food.

Our weakness for junk food might be linked to evolution. Humans may have once developed a preference for high-calorie foods, including sugars and fats, to cope with periods of scarcity. But this hypothesis, proposed in the 1960s, remains subject to debate and has not been confirmed experimentally.

And the role of industry?

Companies obviously want to sell their products – healthy or not – and know how to combine what we want. Advertising and packaging often associate these products with positive emotions and experiences, which works particularly well with children and adolescents. A large study showed that marketing doubles the likelihood of purchasing unhealthy food products.

Are we all equally vulnerable?

No, because we have genetic, physiological, psychological and social differences. Some people easily manage to avoid junk food, or consume it in moderation!

Can scientists make attractive foods healthier?

They are working on it! We can of course think of sweeteners that replace sugar, such as aspartame. But its usefulness is not really convinced the WHO. Others are developing microgels composed mainly of water, from plant proteins. They could – one day – replace fat droplets found in foods. Another one piste: children are often put off by low-fat products. It might be appropriate to limit this information on packaging.

science.lu is Luxembourg’s scientific site intended for the general public. It is managed by the Luxembourg National Research Fundin collaboration with science and research stakeholders in the Grand Duchy.

(Authors: Daniel Saraga (Saraga Communications), Michèle Weber (FNR); Editors: Joseph Rodesch, Jean-Paul Bertemes (FNR))

how does the brain’s reward pathway contribute to junk food cravings?

The Neuroscience of Craving: Why Our Brains Love Junk Food

For many, resisting junk food – those highly palatable, calorie-dense delights – feels like an uphill battle.This isn’t simply a matter of willpower; it’s deeply rooted in our brain’s reward system. Foods high in sugar, fat, and salt trigger the release of dopamine, a neurotransmitter associated with pleasure and reward. This creates a reinforcing loop: we eat the food, feel good, and crave it again.

* Dopamine rush: The intensity of the dopamine release from junk food can surpass that of natural rewards like eating healthy foods.

* Brain’s Reward Pathway: this pathway, crucial for survival (seeking food, water, etc.), is hijacked by highly processed foods.

* Habit Formation: Repeated activation of this pathway leads to habit formation, making cravings more frequent and intense.

This neurological response explains why we often overeat processed foods even when we’re not physically hungry – we’re chasing that dopamine hit. Understanding this food addiction cycle is the first step towards managing it.

The Role of Food Engineering & Sensory Specificity

The food industry invests heavily in “food engineering” – designing foods to maximize palatability and drive consumption. This goes beyond simply combining sugar, fat, and salt.

* Bliss Point: Manufacturers aim for the “bliss point” – the perfect combination of thes elements that creates the most pleasurable sensation.

* Texture & Mouthfeel: Crispy, creamy, and smooth textures are deliberately engineered to enhance the eating experience. Think of the satisfying crunch of chips or the melt-in-your-mouth sensation of chocolate.

* Sensory-Specific Satiety: This phenomenon explains why we can continue eating different flavors of junk food even after feeling full.Each new flavor stimulates a fresh appetite. for example, you might feel full after a large pizza, but still have room for ice cream.

* Hyperpalatability: The combination of high levels of fat,sugar,and salt creates hyperpalatable foods that are exceptionally rewarding and arduous to resist.

Psychological Factors: Comfort Food & Emotional Eating

Beyond the biological and engineering aspects, psychological factors play a significant role in our attraction to junk food.

* Comfort Food: many associate specific foods with positive memories and emotions, turning to them during times of stress or sadness. This is frequently enough referred to as emotional eating.

* stress & Cortisol: Stress increases cortisol levels, wich can trigger cravings for high-calorie foods.

* Learned Associations: We learn to associate junk food with rewards and celebrations from a young age, creating strong emotional connections.

* Food as a Coping Mechanism: For some, junk food becomes a way to cope with negative emotions, providing temporary relief but ultimately exacerbating the problem.

The Impact of Marketing & Accessibility

The pervasive marketing of junk food, particularly targeting children, substantially influences our preferences and consumption habits.

* Advertising & Branding: Aggressive advertising campaigns create positive associations with junk food brands.

* Convenience & Cost: Junk food is often cheaper and more readily available than healthier options, especially in food deserts.

* Portion Sizes: The increasing size of portion sizes over the years has normalized overconsumption.

* Ubiquitous Availability: Junk food is everywhere – gas stations, convenience stores, vending machines – making it difficult to avoid.

The Gut-brain Connection & Junk Food

Emerging research highlights the crucial link between our gut microbiome and brain health.A diet high in unhealthy fats and processed sugars can disrupt the balance of gut bacteria, leading to:

* Inflammation: An imbalanced gut microbiome can trigger chronic inflammation, which is linked to various health problems, including mood disorders and cognitive decline.

* Reduced Nutrient Absorption: Poor gut health can impair the absorption of essential nutrients,contributing to deficiencies.

* Increased Cravings: Certain gut bacteria thrive on sugar and can send signals to the brain that increase cravings for sweet foods.

* Leaky Gut: A compromised gut barrier can allow toxins to enter the bloodstream, further exacerbating inflammation and impacting brain function.

Real-World Example: The Fast Food Industry & Habit Loops

the success of the fast food industry is a prime example of how these factors converge. Companies like McDonald’s have meticulously engineered their menus, marketing strategies, and restaurant environments to create powerful habit loops.

* Menu Engineering: Items are strategically placed on the menu to maximize visibility and appeal.

* Speed & Convenience: Fast service caters to our desire for instant gratification.

* Play Areas & Happy Meals: Targeting children with play areas and toys creates positive associations with the brand from a young age.

* Loyalty Programs: Reward programs encourage repeat visits and reinforce the habit of eating fast food.

Practical Tips for Breaking the Junk Food Cycle

While the allure of