Discuss the practicality of storing energy in early human civilizations and the consequences of these metabolic processes in today’s world. Refer back to the story of the Pima Indians in Chapter 1.4 "Health Factors and Their Impact" and the concept of the “thrifty gene.” Please provide at least one original research article to supporting your examples, in addition to any other external sources, including life experiences. Be sure to use APA format for all citations.
Energy storage was critical in early human civilization. Since there was no technology or large agricultural machinery like today, securing a stable food supply was difficult. Therefore, people worked and lived day by day to eat and survive. Farming was not easy because there was no way to avoid the effects of weather and natural disasters and because there was no knowledge of agriculture. So, their calorie consumption is also expected to be very high.
Therefore, the function of saving the energy ingested through limited food and storing surplus energy as fat in preparation for food shortages was advantageous for the survival of ancient people. Genes that confer traits that conserve energy for daily living and are prone to fat storage are called 'thrifty genes' (Zimmerman & Snow, 2012). In fact, the thrifty gene refers to the thrifty β3 adrenergic receptor gene, and it has been found that carrying this type of gene weakens the action of adrenaline, which breaks down fat, and lowers the basal metabolism by 130-150 kcal compared to those has the non-thrifty type gene (Sipiläinen et al., 1997).
Over 100 years ago, the Pima Indians who lived on the border of the United States and Mexico survived all periods of famine through primitive farming and hunting. Researchers found that the Pima Indians have many thrifty genes, which is thought to be one of the factors that allowed them to survive the famine. Even today, both the Pima Indians living on the US side and the Pima Indians on the Mexican side have many thrifty genes. However, the Pima Indians in the US are more likely to suffer from obesity and diabetes, and the Pima Indians of Mexico are less affected than the Pima Indians of the US (Zimmerman & Snow, 2012). This is because Mexican Pima Indians retain their traditional diet and lifestyle, while American Pima Indians adopt an American diet and modern lifestyle, including high-fat processed foods and refined grains, and their daily activity amount decreased significantly (Zimmerman & Snow, 2012).
In other words, the thrifty genes that favored survival when food was scarce are now the cause of obesity and diabetes when food is plentiful. This suggests that in addition to genetic factors, environment and lifestyle interact to influence our health.
I will share my personal experience. My friend is very slim, even though she hates exercise and spends a lot of time on her couch eating potato chips, playing games, and reading manga. If I did the same, I would gain weight in no time. She eats more than I do. She gets a lot less exercise on her than I do. Yet she never gains weight. All the reasons are due to differences in basal metabolic rate. She must have intense non-thrifty genes and a high basal metabolic rate. Even though she eats a lot and does not exercise much, she still burns a lot of calories while doing nothing. Conversely, she is disadvantageous to her survival when famine strikes in the future.
References
Sipiläinen, R., Uusitupa, M., Heikkinen, S., Rissanen, A., & Laakso, M. (1997). Polymorphism of the beta3-adrenergic receptor gene affects basal metabolic rate in obese Finns. Diabetes, 46(1), 77–80. Retrieved from https://doi.org/10.2337/diabetes.46.1.77
Zimmerman, M., & Snow, B. (2012). 2.4 National Goals for Nutrition and Health: Healthy People 2020. In An Introduction to Nutrition, V1.0. Unnamed Publisher. Retrieved from https://2012books.lardbucket.org/books/an-introduction-to-nutrition/s05-06-a-fresh-perspective-sustainabl.html
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