Women, especially those who enter adulthood with a higher BMI, have a greater risk of age-related weight gain. Weight gain from early adulthood has been associated with an increased risk of heart disease, ischemic stroke, cancer, diabetes, kidney stones, asthma, and even premature death in mid-adulthood. Carrying excess weight poses an additional burden on young women as it increases the risk of ... [Show full abstract] infertility, reduces the success of assisted reproductive techniques and increases the risk of complications during pregnancy and delivery. Data from national surveys, population studies and intervention studies suggests a number of reasons for weight gain in young women. The main reason for weight gain is likely to be due to changes in lifestyle that occur in young adulthood, resulting in higher levels of energy intake and lower levels of physical activity. Further investigations reveal that life events such as getting married, having children, or starting work coincides with weight gain and undesirable changes in lifestyles of young women. Social roles acquired at these milestones may affect the priorities and time availability of young women, which in turn influence their ability to maintain a healthy lifestyle. On the other hand, individual psychological characteristics such as the sense of control over one's health mediate the impact of these life events on the lifestyles of young women. We have noted the high prevalence of weight loss attempts and costly investments on weight management strategies in this group which indicated their strong desire to lose weight. Current research in weight loss suggest that lifestyle modification involving a combination of energy-restricted diets, exercise and behavioural therapy are effective for short term weight loss and metabolic improvements in young women. However, weight loss interventions consistently report a higher dropout rate among young women, suggesting that current weight loss approaches do not meet the needs of this group. From what we have learned about the causes of weight gain in young women, future interventions may need to address the underlying broader issues which shape the lifestyles of young women in order to produce sustainable behavioural change in this group.