DNA vs. Diet: Is Obesity Genetic?
Obesity is currently the leading cause of death in America and most of the developed world. There is no debate. Being overweight leads to increased health risk factors such as heart disease, stroke, and death.
However, the real question that has been lingering in our minds is:
How much of our weight gain is determined by genetics, and how much is caused by diet?
Genes influence every aspect of human life including physiology, body composition, and adaptations. The age old question constantly arises: is it DNA or diet? Is obesity genetic? This has been the subject of debate for years.
Is weight more closely related to nurture or nature?
Diet and exercise are the most critical variables for losing or gaining weight, but exactly WHAT role does genetics play in the grand scheme of things? Is obesity something that is written in our genes or that simply an excuse commonly used to justify being overweight?
Is Obesity Genetic?
A 2014 study discovered that frequently consuming fried food could cause a gene interaction related to obesity. This highlights the importance of reducing fried food intake in people that are genetically predisposed to obesity.
New advances in scientific technology along with the Human Genome Project have identified that genetic factors are responsibly for very RARE, single-gene forms of obesity. New studies have suggested that obesity may be influenced by dozens or even hundreds of genes.
Some forms of obesity may result from spontaneous mutations in a single gene called “monogenic mutations.” These genes affect appetite and energy homeostasis that code for the hormone leptin. Sometimes genetic mutations causing obesity may also be accompanied by mental retardation, reproductive problems, or other health related issues.
Obesity is an issue that is not divided by class, race, income, or sex. Each and every individual has a predetermined genetic selection causing their body fat, overall composition, and muscle growth to differ among one another.
The Obesity Gene
In 2007, researchers using genome-wide association studies identified the first obesity-related gene variant called the “fat mass and obesity-associated” (FTO) gene on chromosome 16. People that carry this particular gene have a 20 to 30 percent higher risk of obesity than non-carriers. Genome wide studies have since identified more than 30 genes on 12 different chromosomes that are related to the body mass index.
While certain genes have been discovered that may affect obesity we have found that genes do not necessarily lead to obesity. In fact, many carriers of the “obesity gene” do not become overweight in their lifetimes and healthy lifestyle choices can counteract certain genetic side-effects.
Although certain genes may carry increased risk factors for obesity in individuals, these genetic chances do not fully explain the exponential rise in obesity around the planet. In fact, the frequency of these genes across the entire human population has remained consistent for several generations. In other words, it takes a substantial amount of time for widespread mutations to occur in the human species.
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The Cause of Obesity
So what has caused these increased rates of obesity over the years?
The one main variable that has changed drastically over the last century has been the social and economic climate that affects the way we eat, live, and interact with one another. Never in history has there been such a wide variety of food so easily available at our fingertips.
We do not have to kill our food nor cook it. We can even order food from the convenience of our cellular phone without having to even speak to another human being. This allows people to eat higher amounts of food with little to no effort whatsoever.
In today’s culture, food is highly processed and refined. Most of the foods consumed by Americans are high in ingredients such as fat, oil, sugar, and salt while being low in micronutrients. Our ancestors did not have the foods we have today such as pizza, Twinkies, donuts, and candy bars. Diets were simple and limited strictly to meat and vegetables for thousands of years.
Our lifestyle and activity levels differ now compared to times past. One century ago, people worked in agriculture and textile businesses which required much higher levels of physical exertion. Today many people work behind a desk with little overall movement. Some even eat lunch at their desk without seeing the light of day for hours.
One study declared that sedentary individuals carrying the gene had higher overall BMI levels than sedentary individuals without the gene. People that carried the FTO gene had a 23 percent higher risk of obesity.
However, in active individuals the genetic predisposition to obesity did not skew results one way or another. Active individuals that carried the obesity gene had a 30 percent lower risk of obesity than inactive adults that carried the gene.
Although genetics obviously play a role in our body composition, the degree of their overall effect is widely uncertain. The scientific research behind the obesity genes are currently in the infantile stages.
What can be said for certain is an active lifestyle with a well-balanced diet can overcome the effects of the gene. One scientist had a declaration that states it best, “Genes may co-determine who becomes obese, but our environment determines how many become obese.”
Making appropriate lifestyle choices will go a long way towards maintaining a healthy and fit lifestyle.
“Genes Are Not Destiny | Harvard T.H. Chan School of Public Health.” Obesity Prevention Source. N.p., n.d. Web. 24 Nov. 2015.