Nontraditional risk factors for obesity in modern society

Overweight and obesity, which have rapidly increased around the world in recent years, are significant health problems. They can lead to various morbidities, including cardiovascular diseases, cerebrovascular diseases, type 2 diabetes, some types of cancer, and even death. Obesity is caused by an energy imbalance due to excessive calorie intake and insufficient energy consumption, and genetic factors and individual behavioral problems are also known to be major contributing factors. However, these are insufficient to explain the surge in obesity that has occurred in recent decades. Recent studies have suggested that environmental factors arising from the process of socioeconomic development and modernization contribute to this phenomenon. These environmental factors include light pollution due to artificial lighting, air pollution, endocrine-disrupting chemicals, and reduced exposure to green spaces due to urbanization of residential areas. In this manuscript, the findings and mechanisms of these novel risk factors causing overweight and obesity are reviewed.