Perceiving the Flavor of Fat

by Julie Terry

When we crave our favorite foods and snacks, those tasty visions in our heads don't usually resemble that of a large, juicy carrot stick or a sumptuous rice cake. We want fat. It's delicious, it's filling, and it just makes everything taste better. It can also make you considerably overweight, not to mention the heart disease and other complications that can result if dietary fat is not consumed in moderation. The appealing taste of fat may very well attribute for the fact that one in three Americans is overweight ("FDA Approves,"1996). Is there anything that can be done about this terrible problem that affects us all? Many researchers say there is. You can either choose to face the facts and simply steer clear of the nasty culprit, or you can fool your taste buds into perceiving the taste of fat without the real stuff ever actually passing your lips. However, before discussing these options, let's talk a little more about fat itself and some of the things it's responsible for.


With the large percentage of Americans that are overweight today, it's no surprise that so many physicians are continually recommending diet changes to their patients. However, the majority of these doctors say that the largest barrier keeping Americans from changing their diets is food taste preference (Soltesz, Price, Johnson, & Telljohan, 1994). The patients don't want to switch to a high-fiber low-fat diet because low-fat high-fiber foods don't taste as good as high-fat low-fiber foods. A big bowl of bran flakes just doesn't have the same calming, pleasurable effects as a big bowl of Blue Bell ice cream. Of course, large individual differences must be acknowledged. Some people may actually prefer the taste of bland foods. In fact, one study done on anorexic individuals found that these people actually disliked the taste of foods rich in fat (Simon, Bellisle, Monneuse, Samuel-Lajeunesse, et. al. 1993).


Much of what we now know about fat and its effects comes from studies done on mice and rats. For example, Rockwood (1990) found that adult rats and developing rats prefer a diet with a relatively high level of fat. In addition to showing that animals as well as humans prefer the taste of fat, there also appears to be a link between fat consumption and behavior. Hilakivi-Clarke, Cho, and Onsjafe (1996) uncovered some startling evidence suggesting that a high-fat diet may induce aggressive behavior in male mice and rats. A similar study (although conducted on humans) concluded that a low-fat high-carbohydrate diet is associated with reduction in depression and aggressive hostility (Weidner, 1994). Thus, enjoying and indulging in high-fat foods in large quantities on a daily basis may not only jeopardize our physical well-being but may jeopardize our mental and emotional health as well.


The actual flavor we perceive once the food is in our mouths results from a combination of taste and smell to add flavor. The actual perception of tasting works like this: Taste particles are sensed by the cells that form the taste buds in the tongue. The neurons associated with these cells send their taste messages to the brain (Freedman, 1993). When food is placed on the tongue, smell particles travel to the olfactory neurons through the "back way" called the nasal pharynx which connects the mouth and the inside of the nose (Goldstein,1996). Aromatic chemicals from the food (outside the mouth) go by the retronasal route by way of inhaled air to the olfactory neurons (Goldstein, 1996). These neurons have cilia that carry receptors for odor molecules. The molecules then bind to their receptors and messages are sent along these neurons to the olfactory bulbs at the base of the brain and then to various other parts of the brain for identification.


So why is it that we enjoy the perceiving the taste of fat so much? After all, it doesn't even constitute one of the four primary tastes of sweet, salty, sour, and bitter. Most likely, genetics have played a large role in our cravings for such fattening items as nachos and pizza. About 3.5 billion years ago, taste and smell were the most important senses, superior even to vision (Freedman, 1993). Our ancestors had to somehow know if what they were eating was poisonous (bitter), unripe (sour), if it could restore lost sodium and potassium chlorides (salty), or if it was a high-energy source (sweet). Also, since fat is a great source of energy, and prehistoric man didn't come across it very often, his taste buds taught him to savor any fat he could get his hands on. However, this has evolved into a problem these days, due to the overabundance of fats in our culture.


What can we do about this endangering health hazard? Certainly we don't have to become martyrs, hating every minute of our meals as we reluctantly force them down our throats to survive. Part of the solution to this problem is awareness. Many attempts have been made across the nation to increase awareness levels. For example, California has instituted the "Five a Day for Better Health Campaign," which features a simple, positive, instructive message to eat five servings of fruits and vegetables as a part of a low-fat high-fiber diet. The campaign appears to have raised public awareness about the ability of fruits and vegetables to reduce the risk of cancer. It also seems to have increased the consumption of fruits and vegetables in major population segments (Foerster, Kizer, DiSogra, & Bal, 1995). However, no matter how much information some people are bombarded with and exposed to, it often simply doesn't sink in. People are not interested in being healthy per se. They just want to lose weight and look better and they enjoy the taste of high fat-content foods. Unfortunately, this latter scenario most likely represents the majority of us.


So if awareness doesn't work, what can be done for these individuals? Can anything be accomplished to allow them to enjoy that succulent double cheeseburger while maintaining that healthy figure? There just might be hope for them (us) after all. Not too long ago, the FDA approved a new fat substitute called olestra to be used in snack foods and possibly other foods down the road. Olestra is a product that tastes almost identical to regular fat but without all the actual fat and calories. The reason it tastes like regular fat is that it is regular fat but without the ability to be absorbed (Institute of Food Science & Technology, 1996). It can be use for deep frying foods and it's cholesterol free. It almost sounds too good to be true. Well, the discussion about olestra doesn't exactly end there. Just like everything in life, there's a flip side to this story, too. The major drawback of olestra is that it interferes with the absorption of vital vitamins such as K, E, D, and A. It also inhibits some of the absorption of carotenoids that are believed to offer some benefits to the immune system. Other cons include a slight aftertaste, possible loose stools, and diarrhea.


If you're not willing to suffer such consequences, there are other fat substitutes that don't carry the risk of such unpleasant side effects. One of these, called Simplesse, is made of whey protein and can be found in baked goods, sauces, dairy products, frozen desserts, and spreads. Salatrim is another reduced calorie fat, but it cannot be used to deep-fry foods. Others include Oatrim, Appetize, and various fruit and vegetable purees. Although these are all beneficial fat substitutes, olestra is the one to keep an eye out for. It has been, and will continue to be, a major source of controversy in the medical field as well as in the food industry. Meanwhile, we can look forward to seeing it in fat-free chips from such brands as Pringles and Frito-Lay("FDA Approves," 1996).


Having said all this, it's all still boils down to individual choice. The individual makes his or her own decisions, including what quantities of what foods go into his or her mouth and body. Until we have a satisfactory substitute for the wonderful taste of fat in our favorite foods (hopefully without all the physical drawbacks) allowing us to literally "have our cake and eat it too" the endless cycles of bingeing and denial and gaining and losing will continue.

 

References

FDA approves olestra as a fat substitute in snack foods (1996). [On-line]. Available: http://www.emerald-empire.com/zines/health/olestra.html


Foerster, S.B., Kizer, K.W., Disogra, L.K., & Bal, D.G. (1995). Californias "5 a day for better health" campaign: An innovative population-based effort to effort to effect large-scale dietary change. American Journal of Preventive Medicine, 11, 124-131.


Freedman, D.H. (1993). In the Realm of the chemical. In B. Jubilan (Ed.), Annual Editions: Biopsychology, 1995/96. (pp. 62-67). Guilford, CT: Dunskin Publishing Group, Inc.


Goldstein, B.G. (1996). Sensation & Perception (4th ed.). Brooks/Cole Publishing Company.


Hilakivi-Clarke, L., Cho, E., & Onojafe, I. (1996). High-fat diet induces aggressive behavior in male mice and rats. Life Sciences, 58, 1653-1660.


Institute of Food Science and Technology (1996, September). Current Hot Topics: Olestra. [On-line]. Available: http://www.easynet.co.uk/ifst/hottop13.htm#top Rockwood, G.A., & Bhathena, S.J. (1990). High-fat diet preference in developing & adult rats. Physiology and Behavior, 48(1), 79-82.


Simon, Y., Bellisle, F., Monneuse, M., & Samuel-Lajeuness, B. (1993). Taste responsiveness in anorexia nervosa. British Journal of Psychiatry, 162, 244-246.


Soltesz, K., Price, J., Johnson, L., &Telljohan;, S. (1994). Family physicians' perceptions of barriers to patients' dietary change. Perceptual and Motor Skills, 78, 968-970.


Weidner, G. (1994). Correlates of health behavior change: The family heart study. CIANS-ISBM Satellite Conference Symposium: Lifestyle changes in the prevention and treatment of disease. Homeostasis in Health and Disease, 35, 235-242.


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