Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health. According to the WHO (World Health Organization) a body mass index (BMI) between 25 and 30 is considered as overweight; a BMI greater than 30.0 is defined as ‘obese’. Globally, 39% of adults aged 18 years and older were overweight or obese in 2016. According to the Global Burden of Disease study* 4.7 million people died prematurely in 2017 as a result of obesity. Worldwide obesity has nearly tripled since 1975. In most high-income countries, around two-thirds of adults are overweight or obese.
Obesity is a disease with many different causes and influences. Genetic, biological, neurobiological, psychological and social factors as well as the living environment may contribute to the development of obesity. Although other factors are involved, the main causes of obesity are an imbalance between calories consumed and calories expended, and a decrease in physical activity. Many causes of overweight and obesity are preventable or reversible by changing the habits of a lifetime.
* Comprehensive global study analyzing 286 causes of death, 369 diseases and injuries, and 87 risk factors in 204 countries and territories.