**Preface to "Eating Disorders and Obesity: Through the Life Course"**

Eating disorders and obesity are two conditions related to eating behaviors which have a significant impact on an individual's physical and mental health over the lifespan. Although they may seem like opposite ends of the spectrum, there are both shared and differential factors that contribute to the development and maintenance of these conditions.

Shared risk factors for both obesity and eating disorders include a genetic predisposition, environmental factors (such as access to healthy food and physical activity opportunities, cultural attitudes toward body size and shape, and social pressure to conform to certain standards of beauty), psychological factors (such as specific personality traits, namely impulsivity, low self-esteem, poor body image, and difficulties dealing with emotions) and some similar metabolic-hormonal factors.

However, there are some differences in the prevalence, clinical features, and risk factors. For example, there has often been a chronic pattern of overconsumption in obesity, whereas there may be more of an acute, later onset of the intermittent pattern of excessive/restrained pattern of food consumption characteristic of binge eating disorder. Moreover, childhood trauma has been found to be a risk factor for the development of eating disorders, while chronic exposure to social and cultural deprivation and alienation may play a greater role in the development of obesity.

Overall, it is important to recognize that both obesity and eating disorders are complex severe diseases that can interact throughout life (in people with eating disorders, lifetime obesity is present in 40% of cases, and 15–20% patients who have obesity also have a comorbid ED). A personalized approach to treatment targeting the various risk factors may be needed. Early intervention and prevention efforts may help to reduce the prevalence of both conditions and improve overall health outcomes. Individuals with obesity and eating disorders have often been subjected to weight stigma and discrimination, which adversely impact their mental health and self-esteem and serve to perpetuate these problems.

> **Fernando Fernandez-Aranda, Janet Treasure, and Empar Lurbe** *Editors*
