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Alternatively: can our genes affect whether we will develop obesity? Obesity is a disease that arises due to a person having a “chronic energy imbalance,” [1]. This means that a person will consume more calories from different foods and drinks, and the excess will be stored as body fat. Although the environment that someone grows up in is a factor when it comes to obesity, genetics also play an important role in this disease and how it develops. It is shown in recent studies that “genetics contribute to 40-70% of obesity with the discovery of more than 50 genes that are strongly associated with obesity,” [2]. Different things that we do can activate these genes. For example, in 2014 a study revealed that “consumption of fried food could interact with genes related to obesity,” [3].
Some rare cases of obesity have been caused by the mutation of a single gene. As listed before, there are around 50 genes that are associated with obesity, but what makes these genes associated with obesity? Well, the genes that can cause these rare cases “play essential roles in appetite control, food intake, and energy homeostasis-primarily, in genes that code for the hormone leptin, the leptin receptor, pro-opiomelanocortin, and the melanocortin-4 receptor, among others,” [3]. Some of the rare types of obesity that can result from the mutation of these genes include “Prader–Willi and Bardet-Biedl syndromes,” and, with them, can come setbacks in mental growth, problems with reproduction, etc. [3]. Usually, these rare types of obesity are also severe. This is because the causes of the mutation of a single gene are “associated with extremely high levels of hunger,” [2]. It also begins in early childhood, which means that it is recommended for children to get screened for these specific traits [2]:
● Leptin Deficiency
● POMC Deficiency
● MC4R Deficiency
Common obesity, which you could probably tell by the name, is one that we see much more often. This type of obesity does not stem from the mutation of one gene, but rather from the mutation of multiple genes that have to do with gaining excess weight. “One such gene is the fat mass and obesity-associated gene (FTO), which is found in up to 43% of the population,” meaning that it is very common for people to have [2]. Other genes like this will increases chances of our weight gain because these genes have control over these weight-gaining traits [2]:
● Feeling hungry more often
● Increased caloric intake
● Not feeling as satisfied after eating
● Having less control against overeating
● Increased time sitting and being sedentary
● The body storing more body fat
Some other genes that play a role in developing obesity are as follows [1]:
● Leptin (LEP)- produced by fat cells
● Leptin receptor (LEPR)- binds to leptin, thus reducing our appetite
● Insulin-induced gene 2 (INSIG2)- controls the way cholesterol and fatty acids interact with each other
● Melanocortin 4 receptor (MC4R)- binds to another melanocyte hormone, making the appetite grow stronger
● Fat mass and obesity-associated gene (FTO)- increases one’s appetite
● Proprotein convertase subtilisin/Kexin type 1 (PCSK1)- controls how insulin makes a chemical compound within the body
● Peroxisome proliferator-activated receptor gamma (PPARG)- develops fat tissue and increases the use of lipids (whose job is to store energy, much like those with obesity store fat)
● Adipocyte, C1q, and collagen domain-containing gene (ADIPOQ)- made by fat cells and increases the level of energy we use up
So how can this information help us in the future? Well, knowing that genes do play a part in if we develop obesity can change the way we prevent it. For example, knowing that “more than 200,000 adults found that carriers of the common FTO gene variant most consistently associated with obesity were able to reduce their risk through physical activity” lets us know that physical activity is a way to reduce obesity, with or without the gene [1]. We also know that “environmental exposures during critical periods of human development can cause permanent changes in a gene’s activity without changing the sequence of the gene itself,” [1]. This means that being exposed to a healthy environment can reduce the risk of causing gene mutations.
Although these genes can play a part in someone developing obesity, it is not destined to happen because they have these genes. Obesity can affect anyone, including “rich and poor, educated and uneducated, Westernized and non-Westernized,” etc. [3]. It is not likely that genes will dramatically affect the way that obesity develops because “the frequency of different genes across a population remains fairly stable for many generations,” [3]. This means that it will take a long time for genes to develop any changes or mutations, and even longer for them to spread. It is shown that “physical, social, political, and economic surroundings” are the major influencers of obesity rates increasing [3]. This is also due to there being little research or evidence on the effect of genes on someone's ability to develop obesity so far.
Treatment is relatively the same for those that contain certain genes listed above, and those who do not carry these genes. Obesity can be battled through the choice of eating healthier foods, increasing physical activity, and limiting activities that require you to sit for long periods (such as screen time). It is getting harder to do these things with the way that society is developing. For example, “the ready availability of food at all hours of the day and in places that once did not sell food, such as gas stations, pharmacies, and office supply stores” is one thing that has contributed to obesity [3]. More often than not, these foods are also “highly processed foods, fast food, and sugar-sweetened beverages,” which are easy to get on the go and taste good enough for us not to think twice about the ingredients [3]. Along with that is a “dramatic decrease in physical activity during work,” which leads to “increased time spent watching television, using computers, and performing other sedentary activities,” [3]. In today’s era of technology, it is not rare to see children watching videos on their phones or playing video games for hours at a time. The number of children that are living this lifestyle has increased dramatically, as technology has come more mobile. For parents, it can be hard to keep their child away from the screen and still maintain their busy schedule, but this age is the most important. Increasing your child’s time outside and promoting healthier food and drink choices can bring obesity numbers down in the future by establishing a healthy lifestyle early on.
Developing a better understanding of obesity and how our environments and genetics can affect our chances of developing the disease is very important. This will help us to tackle these issues in the future and, hopefully, prevent them from ever happening. You can talk to your doctor about getting diagnosed with obesity. You can also have them test you for certain genes to see if you will be more susceptible to developing obesity later in life. Finally, it is most important to just remember to make healthy choices with what you consume, to stay active, and, above all, to be happy doing so.
References:
1. Centers for Disease Control and Prevention. (2013, May 17). Genes and obesity. Centers for Disease Control and Prevention. Retrieved May 19, 2022, from https://www.cdc.gov/genomics/resources/diseases/obesity/obesedit.htm#:~:text=Rarely%2C%20obesity%20occurs%20in%20families,people%20in%20various%20ethnic%20groups
2. Obesity and Genetics - Obesity Medicine Association. Main. (2021, December 10). Retrieved May 19, 2022, from https://obesitymedicine.org/obesity-and-genetics/
3. Genes are not destiny. Obesity Prevention Source. (2016, April 11). Retrieved May 19, 2022, from https://www.hsph.harvard.edu/obesity-prevention-source/obesity-causes/genes-and-obesity/
Contributors:
Author: Kayjah Taylor
Editors: Lauryn Agron and Terin Buckley
Health scientist: Mallory Devine
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