Junk food is highly addictive

Dr Paul Clayton’s Health Newsletter October 2014

It baffles me why anyone would want to eat at any of the US-type fast food outlets. I tried a burger from a leading chain recently, out of a mixture of curiosity and extreme hunger, and found it almost completely tasteless apart from the salt. There was a lot of salt, a good deal of grease, a cheap and nasty white bun (which is turned in the gut into sugar), and a small slab of cooked pink slime – quite revolting, really.

I didn’t stay for long but I couldn’t help noticing that the outlet had a very particular clientele, of a type I have seen in burger and related joints in many countries. Overweight, bad complexions, generally unhappy, poor impulse control (very easily distracted), bad teeth. This is of course a huge generalisation; there are many who do not fit that bill – but it is prevalent.

It is hardly surprising that such appalling food would produce this kind of customer, and nor is it surprising that the developed nations are experiencing such a burden of bad health. This kind of junk diet is deeply pathological. It combines electrolytes in a ration that pre-disposes to hypertension (high blood pressure), with a lack of fibre increasing risk of bowel and many other diseases, an excess of sugars which contributes to diabetes, heart disease and multiple other conditions, an excess of AGEs and ALEs (pro-inflammatory toxins produced when foods are cooked at high temperatures), which are linked to Alzheimer’s, heart disease and cancer, a lack of 1-3, 1-6 beta glucans leading to increased risk of allergy, and a lack of the anti-inflammatory omega 3s and polyphenols which causes chronic inflammation and many degenerative diseases.

So why do folk keep eating this junk? For one thing, it is cheap.

The food industry has been captured by a handful of agro-business companies (Google them!) who grow a very limited number of staple foods such as corn, soy and wheat; and by a slightly larger number of multinational but predominantly American food manufacturers. These corporate players form an oligopoly large and wealthy enough to rent all the regulators and politicians they need, and get them to do more or less what they like. They use this kind of leverage to kill off competitors, and force through government subsidies for themselves; enabling them to produce cheap foods and spend billions advertising their shoddy products.

Cooked and processed burgers, fries and shakes are significantly cheaper than fresh fruits and vegetables, which are not subsidised. And the food manufacturers know exactly how to hit what they call the ‘bliss point’, combining salt, sugars, fats and texturisers with clever marketing strategies to make foods which, scientists increasingly believe, are psychologically addictive (refs 1-6).

A new study (7), in which a junk food diet led not only to weight gain but abnormal and degraded appetite and food selection, adds considerable weight (sorry) to the argument. This study also indicated that there may be an element of physiological addiction, which would explain why excessive consumption of junk foods high in sugar, salt and fat can change behaviour, weaken self-control and lead to overeating and obesity.

In this important experiment, rats fed a cafeteria diet containing high-fat foods such as cookies, dumplings and cake rapidly lost their taste for novel foods (a strategy which favours a balanced diet) and became indifferent in their food choices. In short, a junk food diet was self-sustaining, with poor food choices leading to more of the same poor choices.

The paper suggested that consuming a junk diet caused lasting changes in the reward circuit parts of the rats’ brain such as the orbito-frontal cortex, an area responsible for decision-making. This has definite implications for humans who are probably equally unable to limit their intake of certain kinds of foods, because the brain’s reward circuitry is similar in all mammals. “As the global obesity epidemic intensifies, advertisements may have a greater effect on people who are overweight and make snacks like chocolate bars harder to resist,” said the paper’s lead author.

The case against the food industry looks stronger by the day. If it can be shown that the food manufacturers are aware of the addictive nature of their highly processed products, they will deserve the truly massive lawsuits which will soon be landing in their in-trays. World Health Organisation Director Margaret Chan is leading the way, and has threatened food companies with on-pack health warnings unless they start to shape up.


1. Kelley AE, et al. Opioid modulation of taste hedonics within the ventral striatum. Physiol Behav. 2002 Jul;76(3):365-77. Review.

2. Corsica JA, Pelchat ML. Food addiction: true or false? Curr Opin Gastroenterol. 2010 Mar;26(2):165-9. Review

3. Corwin RL. The face of uncertainty eats. Curr Drug Abuse Rev. 2011 Sep;4(3):174-81.

4. Figlewicz et al. Moderate high fat diet increases sucrose self-administration in young rats. Appetite. 2013 Feb;61(1):19-29.

5. Garber AK, Lustig RH. Is fast food addictive? Curr Drug Abuse Rev. 2011 Sep;4(3):146-62. Review.

6. Ifland JR et al. Refined food addiction: a classic substance use disorder. Med Hypotheses. 2009 May;72(5):518-26.

7. Reichelt AC et al. Cafeteria diet impairs expression of sensory-specific satiety and stimulus-outcome learning. Frontiers in Psychology 2014. Pub online ahead of print, doi:10.3389/fpsyg.2014.00852