Obesity has been defined by experts as “an epidemic” because it affects us 1 billion people in the world and, according to a new study in the Lancet, worldwide among adults it has more than doubled since 1990, and has quadrupled among children and adolescents (from 5 to 19 years): in 2022 43% of adults were overweight. But how does it arise and what diseases can it lead to? We can define it as a condition characterized by excessive body weight due to an accumulation of adipose tissue, which develops due to the interaction of various factors, including genetic, endocrine-metabolic and environmental ones.