To Eat or Not to Eat
Amber Janine Chandler
PSY/240
Saturday, May 5th, 2012
Susan Forde, Ph.D.

To Eat or Not to Eat
The human body needs nutrients to live. In fact, ever body – whether human, animal, or plant – needs nutrients to survive. And the quickest way for organisms to get those nutrients is through food. But what causes us to eat? What motivators push us toward finding that next meal? When do we know when we’re actually hungry rather than simply desiring a snack to pass the time? And, equally as important, how do we know that we have reached the necessary calorie intake level – more commonly known as being “full”? Although there are many factors that influence our hunger and satiety levels, not all of them are completely reliable. In fact, some may lead us very far astray. The feeling of hunger is very real, and can be a very powerful motivator for finding food. But does it always mean that we are actually hungry? Many of us assume that the growling in our stomach is an indicator that we are low on the essential nutrients which provide us with the energy we need to get through the day. However, this is rarely the case. We are likely not starving, and we quite possibly have more than enough stored energy to get through several more hours – or days, if necessary – even if we don’t see another meal in that time. Much more likely is the idea that we are experiencing premeal hunger.
Premeal hunger is the onset of hungry feelings before a meal. These feelings include a decrease in energy and performance, “growling” in the stomach, and perhaps even irritability, light headedness, and fatigue as the oncoming meal approaches. However, all of these symptoms don’t necessarily mean that you are experiencing true hunger. More often than not, it is just the effects of your body preparing to digest a large intake of food.
If you take notice of when these symptoms occur, they most often manifest themselves shortly before a scheduled meal, when you are planning to eat a substantial amount of food. So rather than telling you that you need to eat that much food, your body is preparing to digest it, so it can later regain the homeostasis that you are used to. In contrast, those who eat several small meals or snacks throughout the day, rather than a few regularly scheduled, larger meals are much less likely to experience these hunger pangs. It may also be interesting to note that if you miss your scheduled meal, the symptoms will continue for a while and possibly become more prominent, but will eventually subside. On the other hand, eating the scheduled meal will lead to the subsiding of those symptoms much quicker, and, when the food has positive-incentive value, can contribute to continued satiety later on throughout the day (Isaksson et al, 2011).
Another interesting factor that may contribute to feeling hungry is pavlovian hunger, or the idea that we can be conditioned to feel hungry at the presence of something specific – such as Pavlov’s dog and the bell – even if we are in fact very full. A modern-day example of this would be that of dessert: after a large meal you are most likely feeling as though your stomach cannot hold another bite. Some describe this as feeling as though they might “pop”. Yet when someone presents you with ice cream, pie, cake, or any other number of delicacies, you simply cannot resist indulging in the treat. This is because many of us, as a society, have been conditioned to feel hungry at the sight of dessert even if we are quite the opposite.
Yet another factor which can cause hunger – or the idea of it, which essentially is a myth – is the appetizer effect. When appetizers are served, they generally cause those who partake to feel more hungry than they were before, leading them to eat larger meals. Similarly, if a larger meal is served we are very likely to eat the majority of it, often over eating and possibly even making ourselves ill. On the other hand, if a smaller meal is served, perhaps one with just enough calories to get us by, we would likely be perfectly satiated by the smaller portion.
Of course there are several more severe factors that can affect our feelings of hunger and satiety. Among these are hormone imbalances and damage to the brain. When the brain is damaged – particularly the hypothalamus, the signals that usually tell our bodies when we are hungry and when we are full are no longer as effective. This can cause over eating or possible self-starvation. The hormones that regulate our eating are not regulated properly when the brain has been damaged, and that can easily throw eating patterns off course. Hormones such as cholecystokinin (which causes the gallbladder to contract), ghrelin (which simulates food intake), insulin (which causes hunger), and leptin (a hormone which helps signal that the proper level of satiety has been reached) are all very important to maintaining a healthy eating pattern, and if they are disturbed or thrown off balance, the results could be disastrous. Which leads us into our next topic: obesity and anorexia.
Obesity and anorexia are very severe eating disorders which, if not properly treated, can leave to many serious medical conditions, and even possible death. Obesity and anorexia are, unfortunately, very common problems within the United States, and unfortunately they are not managed as well as they ought to be. There are physiological causes of obesity and anorexia which are not to be overlooked. As was mentioned before, hormone imbalances can cause the body to ignore signals that it has reached its limit, and the person affected may continue to feel hungry even though they are not, or to not feel the pangs of hunger even when they are in dire need of it. This causes him or her to continue eating, which eventually leads to weight gain and obesity, or stop eating altogether, which can lead to anorexia. Genetic factors such as slow metabolism are another important factor, as well. And of course, we cannot forget about pavolvian conditioning, social eating, positive-incentive value of food, and many other psychophysiological factors.
Although there are many factors that can make you feel hungry, it is important to realize when you are truly in need of sustenance, and when you are simply experiencing unnecessary hunger pangs. It is also extremely important to take heed when your body signals to you that you are full, and that you need not continue eating. Ignoring either of these signals could lead to unhealthy eating habits, but recognizing and listening to them can pave the way to a much healthier lifestyle.

References
Isaksson, H., Rakha, A., & Andersson, R., Fredriksson H., Olsson J., Aman P. (2011, April). Rye Kernel Breakfast Increases Satiety in the Afternoon - an Effect of Food Structure. Nutrition Journal, 10, 31.
Physiology of Hunger. (2010). Retrieved from http://www.answers.com/topic/physiology-of-hunger
Pinel, J. P. J. (2009). Biopsychology. Boston, MA: Pearson.