Why don’t I remember that?: Unlocking the mysteries of taste memory

There’s a theory that the reason one can drink endless glasses of cola a day is that it has no ‘taste memory’. What is that and how does it work? Take a look.

Could part of the top-secret Coca-Cola formula be a sense of nothingness?

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American tycoon Warren Buffett has famously said that the drink lacks “taste memory” and that’s why one can consume “one of these at 9 o’clock, 11 o’clock, 5 o’clock... (and not) get sick of it”, while “You can’t do that with cream soda, root beer, orange, grape.”

What really is taste memory? For a while now, researchers have been studying how flavour and short-term memory affect food consumption.

How long-term memory interacts with food choices has been the subject of research for much longer. In 2009, for instance, a study pinpointed that such memories are stored in the gustatory cortex, a region of the insular cortex. (This was a paper by Ivan E de Araujo of the Icahn School of Medicine at Mount Sinai, published in the International Journal of Obesity). The insular cortex is itself a fascinating region. It sits between the frontal and temporal lobes of the brain, and records visceral and emotional sensations relating to events occurring within the body.

But those are the long-term memories. Newer studies are examining how taste influences working memory. A simplified version of the question, for instance, involves figuring out why one can gorge on a favourite food — idlis or parathas or pasta — at lunch, but not want any more, even if one is ravenous, later in the day.

Conversely, why is it that we can consume some foods — say, wafers or cola — in large quantities, and return to them even a few hours later, for more?

One hypothesis suggested that perhaps snacks were easier to return to because they were usually consumed while the mind was distracted. A study by Shirley Xue Li Lim, a postdoctoral scholar at France’s National Institute of Agricultural Research (INRAE), suggests that this is not the case.

Her research, published in the journal Nature in May 2022, involved presenting 21 adults with numerous tastants and introducing sensory distractions. The participants reliably recalled single items, suggesting that tastes were actively and resiliently maintained in human memory in the short-term. It is clear, the paper states, that gustatory working memory is only marginally influenced by the presence of multiple disturbances.

Suzanne Higgs, who researches the psychology of appetite at Birmingham University, offers hints at what the true source of a sense of nothingness or lack of taste memory could be.

In research conducted in 2012 and published in the Springer journal Current Obesity Reports, she explored the phenomenon of “poor food memory” and how it affects consumption. “The consumption of certain foods, in particular those saturated fats and food high in sugar, may impair memory, potentially creating a vicious cycle that promotes overeating,” her report states, “Long-term consumption of a high saturated fat/sugar diet by laboratory rats impair hippocampal-dependent memory processes, which would be predicted to impair food memories and lead to overconsumption of food.”

In the future it will be important to establish the relationship between individual differences in memory and eating patterns and how these may be modified by diet, Higgs adds.

Could the sense of nothingness, then, be traceable to sugar levels so high that they impair certain memory processes in the brain? That might be worth thinking about, before your next sip.