Are your eyes really 'bigger than your stomach'? Studies put it to the test

Story highlights

  • Studies suggest that seeing food contributes to our enjoyment of it and we may eat less of what we cannot see
  • Experts doubt that eating in the dark could be an effective weight loss strategy
  • The relationship between seeing and eating could be flipped on its head at restaurants during enjoying dining experiences

(CNN)Here's an experiment to test and tease your senses: Next time your partner or friend is making you dinner, put on a blindfold before the meal is served. How does not being able to see affect your dining experience?

If you are like the people who have participated in studies exploring the relationship between seeing and eating, you might eat less and not enjoy it as much.
    In a study published in February, researchers in Germany asked 50 volunteers to wear a blindfold while they ate ice cream and compared their reactions with those of 40 participants who saw what they ate. The blindfolded group rated the ice cream as less palatable and pleasant than those who had all their senses at work. They also ate slightly less, but estimated that they had consumed a lot more, based on weight, compared with the no-blindfold group.
    Another small study found a similar phenomenon at play when participants had a lunchtime meal. Those who were blindfolded ate 22% less food than the control group, but reported feeling just as full.
    It could be that there is some truth to that old expression that you were probably annoyed to hear as a child: "Your eyes are bigger than your stomach." In other words, if food looks appealing, you could be driven to take more of it, and maybe also eat more of it. Take vision out of the equation and you could rein in the tendency to overeat.
    But does dining in the dark really take a bite out of how much you enjoy your food? And in the real world, could eating blindfolded really work as a strategy to control your consumption and manage your weight?
    "The single most important aspect of food is how it smells and tastes," but all five senses are involved in our perception of taste, and taking any away, such as sight or sound, could also make you enjoy food less, said Paul Breslin, professor of nutritional sciences at Rutgers University.
    If you were to start sporting a blindfold at mealtimes -- or even wear a nose clip so you couldn't smell -- you might eat less at first and even lose weight.
    "My guess is that it's only going to help for the short term," Breslin said.
    For one thing, your other senses could become heightened and make up for your lack of sight by enhancing your enjoyment of food in other ways.

    Dining in the dark

    When Abigail Hitchcock started doing Dinners in the Dark 10 years ago at Camaje, her bistro in New York's West Village, the goal was certainly not to dilute the culinary experience. She and artist Dana Salisbury actually thought blindfolding guests could enhance their interaction with food.
    "Dana's inspiration was she was having a picnic and closed her eyes when she started to peel an orange and thought it was so much more intense ... and I agreed [eating in the dark] could make it more intense," said Hitchcock, who is the chef and owner of Camaje.
    When diners arrive, they are given a blindfold to put on before they enter the restaurant. From appetizer to dessert, they have no idea what they are eating until the big reveal at the end, when they take off their blindfolds and Hitchcock describes the three-course meal. Guests list any dietary restrictions when they sign up online for the dinners, which are held about once a week.
    Over the years, Hitchcock said she has received a lot of feedback from guests, but no one has complained to her that they didn't enjoy their meal. Almost every plate is empty when it comes back to the kitchen. She thinks not being able to see the food lets people judge it based on taste and smell, and not on some preconceived notion of what they think they like.
    "People are surprised at how much they can get into other senses," such as smells from the kitchen or the sound of a car driving by outside, Hitchcock said. One person discovered she actually likes Brussels sprouts after all. Many realize how sweet it is to not be distracted by their phone during dinner, she added.
    The experience of eating in the dark at restaurants suggests that sight, or the lack thereof, could affect our impression of food differently in the real world than in a lab experiment, said Devina Wadhera, assistant research professor of psychology at Arizona State University, who does research on how our various senses affect food intake.
    "You go to a restaurant, it's expected you'll be eating, and if you go to a lab and eat, it's just an odd situation. A lot of subjects in our experiments will eat less even if they can see the food," Wadhera said.
    Most of these types of studies, including the ice cream study, which Wadhera was not involved in, are carried out in a lab setting. "In one study, I gave mashed potatoes [to participants] and I heard comments like, there might be a lizard in there," she said.
    Wadhera agrees that, in the right environment, eating blind could better, based on her experience at a restaurant in Switzerland called blindekuh, meaning blind cow, which is entirely in the dark. "You can't really see anything, but I know I ate all of it because the food was so good," she said. "I think I would have enjoyed it less because it was very simple, just mushrooms with something, but because I had no vision, I was focused a lot on the taste of the food." The restaurant lets diners read the menu, but they never see the food.
    The idea of serving food sight unseen could be a good way for restaurants to augment their food, or the dining experience, Wadhera said. However she agrees with Breslin that it is probably not really a good weight management strategy for a number of reasons, including that you could probably cheat and use other senses to gauge how much you have eaten.

    Go ahead, try it at home

    Slipping on a blindfold or cutting the lights at home could give you a newfound enjoyment of your dinner, but it is probably not an effective way to cut calories. In the archives of fad weight loss schemes, the "blindfold diet" is probably not going to have a place.
    One study found that, although people who were blindfolded during a meal ate less than those who were not blindfolded, they were susceptible to the effect of portion size. Just like people who saw their food as they ate, the blindfolded group ate more if they had a larger serving. It could be because the blindfolded group saw the food before eating, but not during the actual experience; they knew what was on the plate and might have scaled up their appetite accordingly.
    If you are dishing up your own food, the amount you eat could have more to do how much you serve yourself, and how much you see is on your plate, rather than if you can see your food as you are eating it. It could still come down to willpower.
    Another study, which took place at a restaurant in Berlin and was thus less subject to the "eating in a lab is weird" caveat, found even more discouraging results. Participants who ate in the dark part of the restaurant ate about 36% more food when they were given a super-sized portion, compared with those who got a regular portion. And in this case, they didn't even get a sneak peak at their food. In comparison, participants dining in the front of the restaurant that had light only ate 22% more food when they received the larger serving sizes.
    Moreover, in the Berlin study, participants eating in the dark actually ate more across the board than those who could see their food.
    These studies suggest that eating blindfolded or in the dark does not really make people rely more on cues such as how hungry they feel in deciding how much to eat as you might expect it would, Wadhera said. "People feel the plate with their fork, and touch may be emphasized when your vision is removed and you tend to use these cues to decide how much you want to eat," she said.

    'Eye appeal is half the meal'

    Of all the visual information that we get from taking a glance at a food item, color is probably the most important, said Breslin, the Rutgers professor. Shape, size and lack of blemishes could also play a part if what you are judging is a fruit or vegetable. "If a nice McIntosh apple darkens and turns bright red, that is an indication of it being something we desire," said Breslin, who is also a member of the Monell Chemical Senses Center in Philadelphia.
    These visual cues can provide most of the information that we get about our food before we put it in our mouth, especially if the food does not have a strong aroma, said Alfredo Fontanini, associate professor of neurobiology and behavior at Stony Brook University. Once food is in our mouth, taste receptors in the mouth and cells in the nose detect molecules in the food as we chew, and those interactions determine the food's taste, he said.
    The biggest part that sight plays is in "regulating decisions about what you eat, and it is also important for deciding how much to eat and when to eat," said Fontanini, who studies how food stimuli affect the brain. Sight is probably most crucial for people and other omnivorous animals that eat a range of foods, "whereas if you are a penguin it's pretty much fish," Fontanini said.
    Join the conversation

    See the latest news and share your comments with CNN Health on Facebook and Twitter.

    And what are we looking for when we size up food visually? That its appearance matches our expectations. You might avoid an apple that is blue because you think something is wrong with it. "On the other hand, if you are in a three-star restaurant, or an edgy restaurant, and you are informed by the context that it is safe, you might overcome the innate neophobia," or fear of the new and unknown, Fontanini said.
    In the same way, it might be asking too much of people to eat blindfolded when they are in an unfamiliar environment, Fontanini said.
    Sight could be a special sense because it influences our enjoyment of food just enough, but not too much. Cutting off our sense of hearing, such as by putting in ear buds, would probably not have much affect, said Hitchcock of her Dinners in the Dark. On the other hand, "nose clips would be torture," she said. "Smell is so closely related to taste that it would make your food be really dull."