There’s an old joke about being on a see-food diet ("I see food, I eat it"). Newly published research suggests this obesity-inducing, just-say-yes response to gastric temptation may be based on a fundamental misperception.
Finnish researchers have discovered a connection between body-mass index (a common measure of obesity) and a person’s awareness of the presence of food. They report that, in two experiments, thinner people noticed cakes, cabbages and crackers scattered among other objects more rapidly than their corpulent counterparts.
The notion that fatter people are less likely to notice food may seem counterintuitive, but it proved true for at least one group of Scandinavian students. “We speculate that such differences may constitute an important risk factor for gaining weight,” the research team led by Lauri Nummenmaa of Aalto University writes in the online journal PLoS ONE.
The paper describes two experiments in which undergraduates were asked to pick out food items that were, in the researchers’ words, “embedded in an array of neutral nonfood items” on a computer screen.
“In Experiment One, with visually dissimilar food and nonfood items, 89 percent of the subjects showed faster detection of foods than nonfoods,” the researchers write, “but this detection bias was stronger among the more lean individuals.
“When food and nonfood items were visually matched in Experiment Two (for example, an apple was paired on the screen with a tennis ball), no overall bias towards food was observed in the data,” they write. “However, more importantly, we again found that search performance was negatively correlated with BMI. Those with lowest BMI showed a food detection advantage, and those with the highest BMI showed a food detection disadvantage.”
The researchers are cautious about drawing conclusions from this data. To use an appropriately food-centric metaphor, there is a chicken-egg issue here.
“It is possible that individual differences in food bias could be a risk factor for gaining weight,” they write, “but it is equally likely that increased weight could modify an individual’s biases towards foods.”
In other words, if you’re packing extra pounds, your body may tell your brain, “Relax – you don’t have to hunt for food all that rigorously. We’re OK for now.”
Or perhaps it’s the other way around: The misperception that food is scarce may drive the impulse to overeat. The researchers point out that people “who are effective in detecting nutrients in the environment do not need to stockpile energy resources,” since they’re secure in the knowledge that their nutritional needs will be met.
In contrast, “those whose attention is less biased towards detecting nutrition” may feel the need to “consume foods upon sight.” Of course, all this is occurring on an unconscious level; all we know is we can’t pass up that pizza.
Needless to say, if you’re in that second group and living in a society where fattening food is (contrary to your perception) cheap and plentiful, you have an excellent shot at becoming obese.
Could this misapprehension of food scarcity somehow be modified, perhaps with cognitive-behavioral therapy? It’s certainly worth studying. Self-destructive behavior can often be traced back to what we’re telling ourselves, and this study suggests the urgent internal message to pig out may be based on a faulty premise.