Given the obesity epidemic, wouldn't it be great if there was some way to effectively discourage overeating without placing hard-to-adhere-to backlash-inducing restrictions on our food choices?
A new study suggests such a technique may actually exist—for half the population.
University of Arkansas researchers report men served a hearty breakfast ate less if their meal took place under blue lighting. Unfortunately, this manipulation did not work for women, who apparently rely less on visual cues to determine what and how much to eat.
"Blue lighting can decrease the amount of food eaten by men, without reducing the acceptability of the food," reports a research team led by Han-Seok Seo. Its study is published in the journal Appetite.
Men's sense of smell is "relatively less sensitive," making them "more dependent on visual cues," and thus more easily manipulated by changes in light.
The experiment featured 112 adults, who were seated in "individual sensory booths," which were randomly lit with either white, yellow, or blue LED bulbs. After fasting through the night, each participant was served a breakfast consisting of two ham and cheese omelets and eight mini-pancakes.
After eating as much as they wanted, participants filled out a survey rating the food in terms of flavor and overall satisfaction. The amount they left on the plate was then weighed to determine exactly how much they had eaten.
While their impressions of the food did not vary with the different lighting conditions, men who were served under blue lights ate significantly less than those who did so under white or yellow lights. Afterwards, they reported feeling just as full as their counterparts who ate more.
The researchers explain this using an evolutionary model. "Since naturally blue-colored foods are rare," they write, "humans may have a doubt as to whether (such foods) are safe to eat." On a conscious or unconscious level, participants in the blue-lit booths may have been wary about what they were eating, leading them to stop earlier than they otherwise would.
But why didn't women react in this same way? Seo and his colleagues believe "a plausible explanation" involves "women's superiority in detecting, discriminating, identifying, and remembering odor cues."
Being more "dependent on olfactory cues for their daily decisions, " women "are expected to more easily identify whether or not the served meal is safe to eat, regardless of the lighting color under which it is presented," they write.
In contrast, men's sense of smell is "relatively less sensitive," making them "more dependent on visual cues," and thus more easily manipulated by changes in light.
By design, the study can't tell us whether this tendency will persist if a man eats under a blue light every day. But given how simple and inexpensive it is, it's definitely worth a try—say, in school cafeterias. No matter what his age, if a man is trying to lose weight, it might very well help to have the blue-food blues.