Genetics and Obesity: How Much Does Your DNA Affect Weight?

Obesity is a rising global public health concern that affects more than one billion people worldwide. Lifestyle components like diet and exercise are usually blamed for causing obesity, but do genetic factors also play a role? Solely, genes do not regulate body weight, but when hereditary factors are combined with environmental and behavioral ones, it can influence one’s susceptibility to obesity. Read on to learn more about this.

What Qualifies as Obesity?

Obesity is typically defined as a state of excessive body fat that increases a person’s risk for certain health issues, such as heart disease, diabetes, and hypertension. 

The Body Mass Index (BMI) is the most widely used to categorize obesity. It’s calculated by dividing the individual’s weight in kilograms by the square of their height in meters. According to BMI, obesity is classified into three categories, from mild to morbid:

• Class I: BMI 30-34.9
• Class II: BMI 35-39.9
• Class III: BMI ≥40

To find out if you have obesity, consult a healthcare provider. You can see medical professionals from home, for example, through telehealth platforms like MEDvidi, to have an assessment and receive a weight loss management plan online.

Is Obesity Genetic?

Extensive research has been carried out over the years to explore the link between genetics and weight; currently, from 250 to 550 genes are associated with obesity, according to different studies. These genes can affect the physiological processes involved in weight control, such as appetite, satiety, metabolism, fat storage, and energy use. 

Genes can influence a person’s predisposition to obesity, facilitating or hindering the ability to stay at a healthy weight. Various twin, family, and adoptive studies have shown that the heritability of obesity is between 40% and 70%. However, it is not the only factor.

Types of Genetic Obesity

Genetic obesity is classified into three types based on the genes involved. 

Monogenic Obesity	Polygenic Obesity	Syndromic Obesity
A rare type that occurs due to mutations in a single gene, often beginning in early childhood.	The most common form of obesity that involves multiple genes influencing an increase in body weight.	Occurs as part of a genetic syndrome that includes developmental or neurological abnormalities.
Example: Mutations in the melanocortin-4 receptor (MC4R) gene.	Examples:FTO gene (Fat mass and obesity-associated) — Influences appetite and fat storage.Leptin gene — Regulates hunger and energy balance.PCSK1 gene — Involved in processing hormones that control appetite.	Example: Prader-Willi syndrome caused by genetic mutations affecting chromosome 15. It is exhibited by extreme hunger, intellectual disabilities, and developmental delays.

Mechanisms of Genetic Influence

Some genes control metabolism and define how well the body utilizes food to make energy. They can affect variability in caloric burn, fat storage, and energy usage that influences total weight.

Appetite and satiety (fullness) are regulated through a subtle balance of genetic and hormonal control signals. These important genetic components can include:

• Leptin and the LEP gene: Leptin is a hormone of fullness; mutations in the LEP gene may cause perpetual hunger.
• MC4R gene: Mutations may lead to extreme hunger and obesity.
• FTO gene: Greater expression is linked to higher calorie intake and lower energy expenditure.
• PCSK1 gene: Stimulates hormones controlling appetite, digestion and metabolism.

Environmental Factors

Environmental factors can contribute to body weight gain regardless of the underlying genetic predisposition. Some common examples include unhealthy eating habits, a lack of physical activity, a sedentary lifestyle, and insufficient sleep. However, those who are more susceptible to obesity because of genetic factors might be more sensitive to unhealthy environments. For example, patients with FTO gene mutations can gain more weight when consuming high-calorie foods. In addition, social aspects also play a role. These include lower income, a lack of access to healthy foods, and others.

What to Know About Epigenetics and Obesity

Epigenetic changes refer to the ways in which external factors like environment and behaviors affect how your genes work — but they don’t change the DNA sequence. Triggering factors in terms of obesity may include stress, specific diet, and insufficient exercise. Unlike mutations, epigenetic changes are reversible, so a healthy lifestyle can decrease predisposition to weight gain.

Factors like maternal diet, diet during childhood, and exposure to toxins can also affect obesity risk. For instance, children whose mothers had poor diets during pregnancy could develop a greater susceptibility to obesity.

Treatment and Management of Obesity

Lifestyle Changes

While hereditary tendencies contribute to the risk of obesity, lifestyle changes still play a role in managing weight. Below are some commonly recommended strategies:

• Add whole foods, practice portion control, and reduce sugar and processed foods.
• Exercise regularly, for example, 30 minutes most days of the week. It can be swimming, cycling, walking, or strength training.
• Improve sleep hygiene. Good sleep helps control the hormones that deal with hunger and satiation. Inadequate sleep raises the chances of overeating.
• Try relaxation techniques such as meditation, yoga, or journaling. They aid in paying attention to the body signals and promote mindful rather than emotional eating.
• Seek social support from friends, family, or support groups to keep accountable and motivated.

Medical Interventions

For people with severe obesity, it is essential to contact a qualified medical specialist who can evaluate their health and recommend a course of action. Based on individual needs, some medical treatment options may involve:

1. Medications: Weight-loss medications are usually prescribed for patients with a BMI of ≥30, or ≥27 (in the case of comorbid health conditions). They act in various ways: some help reduce hunger, others block fat absorption, or enhance the sense of fullness. Common obesity medications include Wegovy (semaglutide), Saxenda (liraglutide), Contrave (bupropion-naltrexone), and some others. 
2. Bariatric surgery: Surgery may be considered when other treatments don’t prove to be effective. The results include reduced food intake, decreased absorption of calories, or a combination of these.

Conclusion

Genes do play an important role in one’s predisposition to obesity, but it’s not the only aspect. Environmental and lifestyle factors are important too. However, managing weight is not only about seeing certain numbers on the scale. Overall well-being is what matters most, so your weight management strategy should be comprehensive and personalized. If you think you may need professional help for weight management, consult a healthcare provider for a personalized plan.