Why Fat, Salt and Sugar Stimulate Our Appetite and Promote Over Eating at Times
when we could buy all three in a single carton, we saw that as a great innovation. Now ice-cream has countless flavors and varieties; it comes mixed with M&M’s or topped with caramel sauce.
When layers of complexity are built into food, the effect becomes more powerful. Sweetness alone does not account for the full impact of a fizzy drink – its temperature and tingle, resulting from the stimulation of the trigeminal nerve by carbonation and acid, are essential contributors as well.
“The complexity of the stimulus increases its association to a reward,” says Gaetenp Di Chiara, an expert in neuroscience and pharmacology at the University of Cagliari in Italy. “Elements of that complexity include tastes that are familiar and well liked, especially if not always readily available, and the learning associated with having had a pleasurable experience with the same food in the past.”
” The visual cue gains power and stimulates the urge we call “wanting”. The more potent and complex foods become, the greater the rewards they may offer. The excitement in the brain increases our desire for further stimulation.”
In theory there’s a limit to how much stimulation rewarding foods can generate. We are supposed to habituate – to neuroadapt. When Di Chiara gave animals a cheesy snack called Fonzies, the levels of dopamine in their brains increased. Over time, habituation set in, dopamine levels fell and the food lost its capacity to activate their behavior.
But if the stimulus is powerful enough, novel enough or administered intermittently enough, the brain may not curb its dopamine response. Desire remains high. We see this with cocaine use, which does not result in habituation. Hyper- palatable foods alter the landscape of the brain in much the same way.
When Dr.Di Chiara carried out a research study on an animal, exposing repeated a high-fat chocolate drink. When he’d completed his experiment, he found “Important results!!!!” in the subject line. He had shown that dopamine response did not diminish over time with the chocolate drink. There was no habituation.
Novelty also impedes habituation, and intermittency is another driver. When an animal is given enough sugar-laden food for some time, that food is withdrawn after wards. Then it is provided t again in sufficient quantities, and dopamine levels may not diminish.
There’s still a lot we don’t know about the relationship between the dopamine-driven motivational system and our behavior in the presence of rewarding foods. But we do know that foods high in sugar, fat and salt are altering the biological circuitry of our brains. We have scientific techniques that demonstrate how these foods – and the cues associated with them – change the connections between the neural circuits and their response patterns.
Rewarding foods are rewiring our brains. As they do, we become more sensitive to the cues that lead us to anticipate the reward. In that circularity lays a trap: we can no longer control our responses to highly palatable foods because our brains have been changed by the foods we eat.
Dr David Kessler, former commissioner of the US Food and Drink Administration said, ” I wanted to know how much the industry understood about how the food we eat affects us; about what I have termed “conditioned hyper- eating” – “conditioned” because it becomes an automatic response to widely available food, “hyper” because the eating is excessive and hard to control. I turned to Joseph Stigliz, a Nobel laureate in economics.
“Does the industry know that what it feeds us gets us to eat more?” I asked.”
“The industry has jacked up what works for it,” Stiglitz said. “The learning is evolutionary.” Practical experience has been its guide – it does not need lab rats when it can try out its ideas on humans. Its decision-makers do not have to analyze human brain circuitry to discover what sells.
A venture capitalist who knows the business intimately cited Starbucks as a company that has recognized and responded brilliantly to a cultural need. The caffeine and sugar in the coffee, with their energizing effects, are certainly part of the equation, but the chain also offers something much more primal. “It’s about warm milk and a bottle,” he says. “One of my colleagues said, ‘If I could put a nipple on it, I’d be a multimillionaire’.”
But it was thinking creatively about how to attract more consumers that led Starbucks to the Frappuccino, the venture capitalist told me. Although its stores were crowded early in the day, by afternoon “they were so empty you could roll a bowling ball through them”. The creation of a rich, sweet and comforting milkshake-like concoction utterly transformed the business. A Starbucks Strawberries & Crème Frappuccino comes with whipped cream and 18 teaspoons of sugar: all in all, this “drink” contains more calories than a personal-size