If you’ve struggled with your weight for any period of time, you’ve probably heard a few frustrating adages: “You are what you eat!” or “Calories in, calories out!”
Maybe you’ve tried diet after diet, only to find yourself right back where you started just a few months or years later. Is it what you’re eating? How much you’re eating? What about your exercise? Or, is it just YOU? For many who struggle with weight gain and obesity, yo-yo dieting and the cycle of frustration and triumph are all too familiar.
Obesity in America
Obesity is defined as a condition of having too much body fat. It is often measured using the Body Mass Index, a calculation based on the ratio of an individual’s height to weight. Though the condition is sometimes treated as a cosmetic concern, it’s important to note that a variety of health problems, such as heart disease, stroke, high blood pressure, type II diabetes, sleep apnea, and more, have been linked to being overweight or obese.
Despite the severity of the diseases associated with it, obesity rates continue to rise, with the prevalence of obesity in adults over the age of 20 rising from 13.4% in the early 1960s to 35.7% in 2010, and reaching an astounding 39% overweight and 13% obese adults over the age of 18 in the 2014 U.S population. Today, Americans are more than 24 pounds heavier on average than they were in 1960.
On a global scale, obesity has reached epidemic proportions with approximately 1.5 billion adults reaching the overweight or obese categories. Some studies suggest that number may reach 3 billion by 2030.
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Obesity and Genetics – How it Can Impact You
The concept of nature versus nurture is a timeless and ongoing debate among the scientific community and has only recently been applied to a person’s propensity toward obesity.
For years, many scientific and non-scientific minds alike believed that the environment we’re exposed to as we grow up contributes more to our specific traits than do any hereditary factors.
As it turns out, that might not be the case.
Beginning with studies published on twins in the 1970’s and accelerated by the availability of genetic testing after the completion of the Human Genome Project, people began to question the notion that traits are determined primarily by the environment. Instead, work within the scientific community has transitioned toward understanding the role that genetics play in determining what makes you, well, you.
In recent years, research has revealed a strong contribution of genetics in determining a person’s body mass index (BMI) and predisposition toward obesity. In fact, this genetic influence may be so significant that some studies have estimated that body weight and obesity are 65-80% predetermined by a person’s genetic makeup.
Is Obesity Genetic?
Over time, the number of genes associated with obesity has grown. Researchers have focused on two primary types of obesity: monogenic and polygenic obesity. Monogenic obesity is a condition in which individuals with specific mutations in a single gene can lead to obesity.
Polygenic obesity, on the other hand, the more common form of obesity, refers to obesity that is caused by the combined effect of multiple genetic variants. In 2001, researchers found six genes linked to monogenic (single gene causing) obesity and none to polygenic obesity. In 2008, this number grew to eight monogenic genes and four polygenic genes.
Recent estimates have found nine genetic locations directly associated with obesity and 58 mutations that have a combined effect on this condition. Clearly, the understanding of the human genome is continuing to grow simultaneously with the understanding of human diseases.
A study that included 775 adult bariatric patients and 3197 control patients found that participants with a specific mutation in the FTO gene had an almost 1.5 times greater likelihood of being extremely obese than those without the mutation.
The research behind these genetics links to obesity isn’t limited to adults either. Studies on children have also shown a genetic influence on obesity.
Genetic testing done on 1,509 children with extreme obesity and 5,380 normal-weight children found that mutations in four genes (LEPR, PRKCH, PACS1, and RMST) were associated with extreme obesity, with mutations in these genes raising the likelihood of severe early-onset obesity 1.42, 1.5, 1.22, and 1.67 times respectively.
The association between mutations in several other previously studied genes and obesity were also replicated in this study.
With all these statistics, it’s easy to feel discouraged.
The good news is that people can and do overcome this genetic propensity toward obesity every single day. People who are genetically at risk for weight gain and obesity can utilize information from DNA testing to make better-informed lifestyle decisions and changes that will help them reach their peak health.
With proper nutrition and lifestyle changes, it’s possible to reach and maintain a healthy weight even if you do carry a predisposition toward obesity. Time and again, it’s been proven that small and consistent changes in nutrition, exercise, sleep, and supplementation can make a big impact on your overall health.