Written on June 18, 2023 by Amy Harris, MS, RN, CNM. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
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Genes are important when it comes to your health, but they are not the only factor determining how long or healthy your life will be. Regarding obesity, we know that other factors, such as the environment you live in, the food you eat, the kind of life you live, and how physically active you are, all play a role. As medical researchers and healthcare providers search for better ways to treat obesity, we learn more daily about genetic obesity. Stay tuned to learn more about genetic obesity and the future of weight management with precision medicine.
Genes store all of the information that tells your body how to do its job, almost like the hard drive for a computer. DNA is the building block that makes up your genes. You inherit a unique mixture of genes from your biological parents’ genes.
Genes are important for health because they contain information about your risk for certain diseases, such as obesity. Changes in genes or chromosomes can cause a genetic disease. So, now that you know what genetic means, let’s try to explain obesity. Because, as it turns out, obesity can mean many different things to many different people.
You may have heard much debate in the news recently about how to talk about obesity. Maybe this debate has made you wonder, “Am I obese?” Or, given that four out of every 10 Americans is obese, your healthcare provider may have talked to you or a loved one about obesity and weight-related comorbidities at your last appointment.
Well, let’s try to understand the truth about BMI and weight management before deciding whether or not it describes you. Obesity is a category of body mass index (BMI) — a mathematical calculation used as a screening tool. Healthcare providers define obesity as the range of BMIs between 30 and 34.9.
As you have probably noticed, people come in various body sizes and shapes. So, healthcare providers use a BMI scale to see how your BMI compares with everyone else’s. BMI is a screening tool for individuals but does not diagnose body fatness or health.
Genetic obesity is a type of obesity theoretically caused by your genes. Unfortunately, obesity is multifactoral (caused by much more than just genes). This is why it has proved so hard to find a cure for obesity. As scientists and researchers have begun to decode genes, they have shown that there may be as many as 100 genes and gene variants associated with obesity.
Three very rare types of genetic obesity cause children to become severely obese as young as age 2. A defect in one gene causes these disorders. They are Leptin Deficiency, POMC Deficiency, and MC4R Deficiency.
Unlike these rare types of single-gene genetic obesity, most obesity appears to be caused by multiple genes. It is also true that not everyone carrying these obesity genes will be obese. While the DNA or genes may account for 40% to 70% of obesity, many other factors determine whether or not someone is obese. The kinds of foods a person eats, their physical activity level, other medical conditions or disease, and social determinants of health also determine whether or not they are obese.
Genes control how your brain regulates your food intake. Hormones (chemical messengers) from your fat tissue, your pancreas, and your digestive tract (stomach and intestines) all communicate regularly with your brain via hormones you may have heard of — leptin, insulin, and ghrelin.
Genes are the basis for the signals and responses that guide food intake, and small changes in these genes can affect their levels of activity. The brain regulates how much food you eat by responding to signals received from fat (adipose) tissue, the pancreas, and your digestive tract. Leptin, insulin, ghrelin, and other small molecules transmit these signals from your digestive tract to your brain. The brain coordinates these signals with other inputs. Your brain then directs you to eat more and work out less or to do the opposite.
No. Genetic tests for so-called “obesity genes” are not yet commercially available. There is debate among healthcare providers, public health researchers, and the fat-activist community as to whether such tests would be ethical or helpful. Critics fear genetic tests for obesity would lead to further stigmatization of people with larger size bodies. Other arguments against genetic testing for obesity are that:
While tests are yet available, precision medicine delivers new treatments for genetic obesity nearly every day. Precision medicine for obesity means personalized treatment plans. Moving past the one-size-fits-all approach to treating obesity, precision medicine can tailor care based on a better classification of different types of obesity.
Scientists and researchers have begun to develop specialized medications which target some of these misbehaving genes that interfere with chemical messaging about food intake. One example is a GLP-1 agonist such as Ozempic® (semaglutide). In June 2021, the U.S. Food and Drug Administration (FDA) approved Ozempic® injection (2.4 milligrams once weekly) for chronic weight management in adults with obesity or overweight with at least one weight-related condition (such as high blood pressure, type 2 diabetes, or high cholesterol).
Semaglutide works to cause weight loss and treat diabetes by mimicking one of those appetite and food intake-regulating hormones. The hormone semaglutide is a glucagon-like peptide-1 (GLP-1). For some people with larger-sized bodies who couldn’t lose weight by dieting or who have fought a life-long battle against obesity, these specialized medications offer a chance to live a longer, healthier life. Short-term research (one year only) showed that Individuals who received Ozempic® lost an average of 12.4% of their initial body weight compared to individuals who did not receive Ozempic®. For a person weighing 200 pounds, this would be about 25 pounds.
You probably have heard about newer “miracle weight loss drugs” and might be wondering whether the GLP-1 agonists will work for weight loss for you. This is especially true if you think genes are behind your weight challenges.
Combined with sustainable changes in your diet and physical activity level, GLP-1s and other precision medicine treatments for obesity may help you live a longer and healthier life. Through Everlywell, you can book virtual care visits for online weight management to meet with a healthcare provider and discuss the best options for your long-term health.