Why Obesity Is More Complex Than It Seems
Severe obesity is becoming increasingly common worldwide, and in many families, several members struggle with excess weight. Although society often views obesity as the result of an unhealthy lifestyle, science shows that genetics also play a major role. Poor diet and lack of exercise contribute, but they are not the only causes — obesity is a combination of biology and environment.
The Inherited Tendency to Gain Weight
Twin studies reveal that 60–80% of body weight is influenced by genetics. Adopted identical twins resemble their biological parents in terms of BMI far more than their adoptive families. Even identical twins raised in different households have remarkably similar body weights, which highlights the strong influence of genes. Researchers now know that genes affect satiety, fat metabolism, and fat distribution, as well as how much energy the body uses at rest and how strongly someone feels the urge to move.
How Genes Contribute to Obesity
Family studies further confirm that a genetic predisposition increases the risk of obesity. For example, children with two parents who have obesity face a much higher risk of becoming overweight—even if they grow up with healthy eating habits and regular activity. Scientists have already identified multiple genetic variants associated with weight regulation. Around one in five children with severe obesity carries a genetic variant that disrupts the brain’s hunger and satiety signals, causing weight gain at a very young age.
Genes Alone Do Not Determine Your Future
A genetic predisposition does not mean that obesity is inevitable. While genes may set the stage, factors such as diet, physical activity, environment and daily habits strongly influence whether someone actually develops severe obesity. In other words, genetics explain the risk — but lifestyle determines the outcome.
The Balance Between Genetics and Lifestyle
Although you cannot change your genes, you can influence how they affect your health. Healthy eating, regular exercise, and long-term behaviour change can help counteract the genetic tendency toward obesity. Your genes may make the journey more challenging, but they do not remove your ability to improve your health or manage your weight.
