Finally, a scientific reason why I keep forgetting that bag of carrots in the back of my fridge until they turn into a mouldy, noodley tangle! Researchers at Wageningen University & Research in the Netherlands have shown one particular way in which humans have retained our “Stone age brains”: We are hardwired to remember the locations of calorie-dense foods far more accurately than “lighter” foods. Bye-bye, carrot sticks; hello carrot cake.
The study involved 512 participants, who were each guided through a room where the researchers had planted eight samples of actual foods or eight food scents (on cotton pads). The participants smelled the foods or food scents, and then rated them by how appealing they found them. Half of each kind of sample were high calorie (like brownies and potato chips), and half were low calorie (like apples and cherry tomatoes). When the participants were later asked to point out the samples on a map of the room, they were 30% more accurate at recalling the locations of the high-calorie samples — and 243% more accurate when the foods were real, instead of just scents.
“‘Our main takeaway message is that human minds seem to be designed for efficiently locating high-calorie foods in our environment,’ says Rachelle de Vries, a Ph.D. candidate in human nutrition and health at Wageningen University and lead author of the new paper. De Vries feels her team’s findings support the idea that locating valuable caloric resources was an important and regularly occurring problem for early humans weathering the climate shifts of the Pleistocene epoch. ‘Those with a better memory for where and when high-calorie food resources would be available were likely to have a survival — or fitness — advantage,’ she explains.”
Once upon a Pleistocene, this cool talent saved our bacon. But there is a downside for today’s humans. For those of us lucky enough to live where sugar and fat are readily available, the ancient instinct to zero in on it and eat as much as possible (lest we not find another source for months, or get gored by a mammoth tomorrow) is a contributing factor to the modern scourges of obesity and diabetes. Retraining our brains in a habit that is so deeply ingrained may not be possible — so I plan to rely on my frontal lobe writing me a sticky note on my fridge, that just says “CARROTS.” Once remembered, whether or not I eat them is another story…!