The following theories of the causes of obesity aim that readers will acquire a more thorough understanding of obesity, and help eradicate false notions on the nature of this health condition.
The Settling Point Theory as a Cause of Obesity
This theory claims that “overeating" during childhood stimulates the body’s production of more fat cells for the storage of excess fats. As a person grows to adulthood, the fat cells continue to store more fats making adipose tissues become more massive. The theory says that compared to people of a healthy weight, obese people possess more fat cells, which increase their capacity to store fats.
The theory of the cause of obesity adds that the body mechanisms of obese people to inhibit fat intake (if there is already enough fats ingested) and to relieve hunger (if the person is already full) is slow. The body mechanisms might involve the brain’s delay or failure to send signals to the “hunger center" of the brain to “tell" the person that he is already full. The consequence of this problem is that the excess fats ingested are deposited to fat cells in adipose tissues.
Furthermore, the theory claims that the weight of obese people has a “settling point" that any deviation from it is prevented by physiological means. The “settling point" is comparable to the 37 degrees Celsius constant body temperature of human. This can be observed when an obese person’s metabolic rate drops as that person loses weight through diet. We know that low metabolic rate inhibits fat burning; this makes the diet futile. When an obese person then begins to gain wait, his metabolic rate soars up and his appetite is enhanced. The lost in weight is regained three times faster until the “settling point" is reached. (Marieb 2006)
Fuel Efficiency Theory as a Cause of Obesity
This theory claims that obese people are “more fuel efficient" and better “fat storers" (Marieb 2006). Perhaps everybody has the notion that an obese people eat more food than normal persons that is why their body “ballooned". This is not totally correct because some people who are considered obese actually eat less food than normal weight people.
Molecular observation on the fat cells of obese people reveals that they (fat cells) extend more alpha receptors from their plasma membranes than what is observed in normal persons. These alpha receptors are the sites where fatty acid and glycerol molecules bind; they are also responsible in transferring these molecules toward the cytoplasm. Therefore, the more alpha receptors, the more efficient are the entry of fats towards the cell’s cytoplasm. Furthermore, fat cells of obese people secrete high amount of lipoprotein lipase enzymes responsible in unloading fats from the blood towards fat cells. The effect is again more fat deposition to fat cells.
Genetic Predisposition Theory as a Cause of Obesity
This theory of the cause of obesity is based on genetics: the study of heredity. Genetically obese parents can transfer their obesity genes to their children. When the obesity genes are expressed, the tendency for the obese person is that any excess calorie he consumed is deposited as fat instead of being processed for the formation of muscles (as observed in a normal person). Scientists have already identified 250 obesity genes in mice and man (Foster 2008) but their modes of expression are not yet understood. However, they believe that the environment has a strong influence in activating these genes to be expressed. One case study that supports this theory is an adopted child who grows to be like his obese parents even though his “legal parents" did not fail to guide his eating habits. The child did inherit his “real" parents’ obesity genes.
Foster, Gary D. "Obesity." Microsoft® Student 2008 [DVD]. Redmond, WA: Microsoft Corporation, 2007.
Marieb, Elaine. 2006. Essentials of Human Anatomy and Physiology. Singapore: Pearson Education South Asia Pte. Ltd.