Summary
Significant weight gain occurs in women during young adulthood, which increases risk of diseases such as diabetes, cardiovascular disease, and many cancers. This review aims to inform future individually targeted weight gain prevention programmes and summarizes possible targets: key life events, mediators that influence energy intake and physical activity levels, and moderators that could identify groups of women at greatest risk. Life events affecting weight include pregnancy and motherhood, smoking cessation, marriage and cohabiting, attending university, and possibly bereavement. Research has identified successful methods for preventing weight gain associated with pregnancy and motherhood, which could now be used in practice, but evidence is inconclusive for preventing weight gain around other life events. Weight gain is mediated by lack of knowledge and skills around food and nutrition, depression, anxiety, stress, satiety, neural responses, and possibly sleep patterns and premenstrual cravings. A paucity of research exists into altering these to limit weight gain. Moderators include socioeconomic status, genetics, personality traits, and eating styles. More research is required to identify at‐risk females and engage them in weight gain prevention. There is a need to address evidence gaps highlighted and implement what is currently known to develop effective strategies to limit weight gain in young women.