Why Children are Vulnerable to Unhealthy Eating

Examining the Human Brain

©Eric Miller
Children in Atlantis, Western Cape, buy junk food snacks during their break period.
Why is it that our children are so vulnerable to the seductive lure of fast foods and the advertising advances of the multinationals that are increasingly turning their attention to the African continent as a new market in which to peddle their wares? Psychiatrist and University of Cape Town lecturer Dr John Parker, from Lentegeur Psychiatric Hospital in Cape Town, explains that this is largely a function of how the human brain develops, and how it responds to the temptations of potentially addictive substances such as drugs or fast foods.

Let us start by imagining we are viewing a cross-section of the brain that looks something like a Russian doll. The little doll on the inside is the ancient reptilian brain and the first part of the brain to develop in a human. It is the seat of our instinctive responses such as behaviour associated with dominance, aggression, ritual and territoriality. This, in a way, is the hair-triggered infant brain.

Limbic System and Neocortex

Next to develop, the middle doll in the cross-section, is the limbic system of the brain, the so-called palaeo-mammalian brain. This is the engine room of our motivation and drive regarding eating, parenting and sex and it is where the reward centre of the brain sits. This is where the act-now-think-later responses take place, and it is the stimulation of this part of the brain that leaves us vulnerable to addictive behaviour, whether it be to drugs, sex, spending, gambling or food.

The outer ‘big doll’ is the neocortex – the ‘new’ or neomammalian brain and the most recent addition to our evolving brain – which processes the cognitive functions we associate with being an adult: the ability to plan, to process language, to think abstractly, to perceive. This part of the brain, and particularly the prefrontal cortex associated with what are known as the executive functions – processing information, inhibiting immediate impulses and planning future acts – has only developed fully by the time we reach our mid-twenties.

Cognitive Struggles in Delaying Gratification

So we only become fully reasoning adults well beyond our adolescent years, and a good few years after the state has declared us to be legally responsible. This ‘limbic’, middle-doll brain dominates many of our responses to the world at a time when the final ‘adult’ brain has yet to flesh itself out and try to exert itself as our behavioural boss.

The famous marshmallow experiment shows the middle and outer dolls struggling for power: sit a child down with a marshmallow in front of her, with the instruction that she can eat the one marshmallow now, or if she waits for fifteen minutes, she will get two. Then leave her to her own devices. What follows is a wrestling match between her limbic brain, which wants the pleasure of the sugar now, and the strategic planning processes of her underdeveloped neocortex, which tells her rationally that if she waits, she will get double the reward later. More sophisticated experiments show that even in adults, when faced with choosing between R100 now or R1 000 in a week’s time, the same cognitive struggles are at work. The stronger or more developed the workings of the neocortex, the better the individual will be at delaying gratification, Parker explains.

Reward Centre Overrides Rationality

©Andile Bhala
Children and adolescents are more likely to impulsively feed the reward centre of their brain with junk food that tastes good.
This is where willpower comes in – the ability to resist the impulsive drive to indulge in the moment. So it follows that for a child or adolescent, whose neocortex is still just beginning to build itself, their behaviour is going to be dominated by the limbic reward-driven part of the brain and leave them wide open to impulsive behaviour regarding potentially addictive foods.

Interestingly enough, adult addicts’ brains work in a similar way to the adolescent brain, where the reward centre overrides the brain’s ability to pause in that decision-making moment, to think rationally about the consequences of the decision and respond accordingly. Every time a struggle like this ensues, and every time the limbic brain wins, says Parker, a person has the potential to slip closer and closer towards addictive behaviour. It has been described rather eloquently as the ‘tyranny of small decisions’ – a series of little decisions which, in the moment, seem inconsequential, and yet over a period of time lead to the descent into patterns that can seriously compromise one’s health.

Youngsters Prioritise Immediate Gratification

That is why it is so easy for youngsters to be seduced by the fats, salts, sugars and flavourings that are found in many processed foods, and slip into addictive behaviour patterns. And once those patterns are established in pre-adults, it becomes difficult to change behaviour later in life. Further to this, the World Health Organization’s Dr Boyd Swinburn, from the Collaborating Centre for Obesity Prevention, maintains that children are particularly vulnerable because their lack of maturity and nutritional literacy leaves them unable to fully understand the risk associated with their behaviour regarding food, leaving them suggestible to marketing messages.

A ‘hallmark of childhood’ is that youngsters tend to ‘prioritise immediate gratification over potential long-term negative results’, says Swinburn, which is why the market fails our children by targeting them with these foods and exploiting their lack of maturity and vulnerability. This is the underlying thinking behind a call by obesity experts for a more concerted intervention by the state in terms of regulating the behaviour of the fast food sector – both in terms of what foods it produces and how it markets them. And yet, Parker warns against relying too heavily on this ‘nanny state’ response to the problem. It is equally important to give our teenagers and children the skills they need to face the food temptations that are before them every day, and engage in cognitive processes in the moment that protect them from that tyranny of small decisions in the long term.

By Leonie Joubert