Obesity is the oldest and still the most common metabolic disorder in humans. It has been depicted in sculptures of ancient civilizations, and until the 20th century was considered an aesthetic problem or ideal of beauty in some cultures. Today, obesity is classified as one of the most common diseases of modern civilization, affecting around 15% of the global population. The causes of obesity are complex and include genetic, cultural, social, metabolic and physiological factors interacting with lifestyle habits like diet and physical activity level. Prevention is key to reducing the burden of diseases associated with obesity.