The prevalence of obesity increases with age but is apparent even in early life. Early childhood is a critical period for development that is known to influence future health. Even so, the focus on obesity in this phase, and the factors that affect the development of obesity, has only emerged over the past two decades. Furthermore, there is a paucity of iterative work in this area that would move the field forward. Obesity is a complex condition involving the interplay of multiple influences at different levels: the individual and biological level, the sociocultural level, and the environmental and system levels. This Review provides a brief overview of the evidence for these factors with a focus on aspects specific to early life. By spotlighting the complex web of interactions between the broad range of influences, both causal and risk markers, we highlight the complex nature of the condition. Much work in the early life field remains observational and many of the intervention studies are limited by a focus on single influences and a disjointed approach to solutions. Yet the complexity of obesity necessitates coordinated multi-focused solutions and joined-up action across the first 2,000 days from conception, and beyond.

肥胖的患病率随着年龄的增长而增加，但即使在生命早期也很明显。幼儿期是已知影响未来健康的关键发展时期。即便如此，这一阶段对肥胖的关注以及影响肥胖发展的因素，只是在过去二十年中才出现。此外，该领域缺乏能够推动该领域向前发展的迭代工作。肥胖是一种复杂的疾病，涉及不同层面的多种影响的相互作用：个体和生物层面、社会文化层面以及环境和系统层面。本综述简要概述了这些因素的证据，重点关注早期生活特有的方面。通过突出广泛影响（包括因果和风险标志物）之间的复杂相互作用网络，我们强调了该病症的复杂性。早期生活领域的许多工作仍然是观察性的，许多干预研究受到对单一影响的关注和脱节的解决方案方法的限制。然而，肥胖的复杂性需要在受孕后的前 2,000 天及以后采取协调一致的多重点解决方案和联合行动。