Adverse childhood experiences (ACEs) can become biologically embedded leaving a lasting signature on multiple body systems. ACE scores have been used to associate childhood adversity to a wide range of adverse health conditions over the life course, most notably substance-related disorders. Multiple studies have shown that the presence of elevated ACE scores predicts obesity in adulthood. However, a gap exists in the literature elucidating the pathways from childhood adversity to increased BMI in adulthood. We systematically reviewed these mechanisms as well as discuss novel plausible pathways. We searched PubMed, PsycInfo, Embase, and Web of Science and after applying exclusion criteria identified 18 articles for qualitative analysis. The most commonly cited mechanisms linking ACEs to obesity are social disruption, health behaviors, and chronic stress response. Ten observational studies (n=118,691) were quantitatively summarized and demonstrated a positive association between ACE and adult obesity with a pooled odds ratio of 1.46 (CI=1.28, 1.64) with moderate heterogeneity (I=70.8%). Our results found a 46% increase in the odds of adult obesity following exposure to multiple ACEs. Based on our qualitative synthesis and review of the most recent relevant literature, we propose biologically plausible explanations for the significant positive relationship between ACEs and adult obesity. Reducing exposure to ACEs, improved screening and detection of trauma, better access to trauma-informed care, and improvements to the food environment are likely to improve downstream health outcomes related to eating behavior.