Hunger is a biopsycological process that is critical for organisms to survive. It is a biological process because it involves metabolic processes and hormones. It is physiological that in that it creates a physical need that has to be satisfied. The hypothalamus is the brain part that is responsible for controlling the hormonal function in the body.
Carnivores depend on other animals for food. Though at times they can feed on plants, their bodies are not physiologically able to digest vegetables matter. Carnivores require heavy meals but can spend most of the time without eating (DeGroot 3024). Unlike carnivores, omnivores have the ability to eat and digest both animal flesh and vegetables.
Most omnivores eat relatively small meals but periodically. They normally cannot have a single meal in a day. Herbivores are animals that feed on vegetables only. Their taste preferences are uniquely on vegetables and their bodies cannot digest anything else but vegetables (DeGroot 3024). Most herbivores feed for the better part of the day and sleep over the night.
Factors that Influence Hunger
Leptin
Scientists have determined that a hormone called leptin controls the brain circuits responsible for controlling hunger. Leptin inhibits appetite by acting on receptors in the hypothalamus. First, it counteracts the effects of neuropeptide Y which is a potent feeding stimulant secreted by cells both in the gut and in the hypothalamus (Liu, et al. 2754).
Secondly, it counteracts the effects of anandamide and thirdly it promotes the synthesis of an appetite suppressant called α-MSH. Unlike the rapid inhibition of eating by cholecystokinin (CCK) and the slower suppression of hunger mediated by PYY3-36, the inhibition of leptin is long-term. The absence of this hormone leads to uncontrollable eating habits and ultimately obesity.
Cholecystokinin
This is another hormone responsible for the control satiety and is produced by the duodenal and intestinal mucosa (Liu, et al. 2754). It does so by controlling the speed of digestion in the body. High fat chime stimulates the production of this hormone, which through a chain of reactions reduce the speed of digestion.
Peptide YY
This is a 36-amino acid protein released in response to feeding by the neuro-endocrine cells in the ileum and colon. This hormone appears to reduce appetite in humans (Liu, et al. 2754). Though it is not clear how this hormone reduces satiety, it is clear that it slows the gastric emptying thus increasing the efficiency of digestion and nutrient absorption after a meal.
Genes: Is obesity genetic?
Epigenetics have revealed some genetic characteristics that control the energy levels in the body. One of the impairments that lead to uncontrolled appetite is the Prader–Willi syndrome (PWS). People with this disorder develop uncontrollable appetite, which may result to severe obesity. This I just an example. Many other genetic imprints associated with the eating disorders but no scientific evidence has proved the genetic proof of the epidemic.
How experiences have affected my feeding
My individual eating habits have been greatly influenced by experiences. First, personal skills have affected my choice of foods. The knowledge on cooking and preparing variety of dishes has increased my variety of choice. Another influence has risen from the cultural background, which has determined my basic foods. During the study, I did not find any genetic influence on my eating habits.
The Interactions between nature and nurture that affect diet, body size/shape
Several interactions affect diet, body size/shape. In the prenatal period, the availability of food to a pregnant mother affects the nutrients availability of the developing fetus thus its eventual body size/shape. If the developing child does not have access to adequate nutrients, it ends up being small-bodied besides having a low birth weight. Owing to this, during childhood as well as the other stages of development, such a child requires a diet that is capable of supplying all the essential nutrients for a healthy growth.
Additionally, the body weight of a mother during pregnancy also affects the diet of a child. Mothers who have high body weights as well as those who gain a lot of weight during pregnancy tend to give birth to children who at risk of being overweight by the time they are three years of age. Such children/individuals have big bodies thus require a diet that is instrumental in reducing their weight as well as maintaining a healthy body weight and shape.
Works Cited
DeGroot, Leslie, et al. Endocrinology. Philadelphia: Saunders. 1989. Print
Liu, McFadden, et al. “Peptide YY: a potential proabsorptive hormone for the treatment of malabsorptive disorders.” Am Surg. 62 (1996): 232–236. Print