Marriage and parenthood are major life events for many individuals. Marriage is linked with improved health partly through spousal influence on health-related behaviors including diet. Previous theoretical and qualitative research suggests a link between family transitions and meal patterns. Yet empirical research using a nationally representative sample to examine the association is scarce. And the issues of whether spousal influence on health-related behaviors can be extended to other types of romantic relationships, such as cohabitation, as well as whether the transition to parenthood is linked with changes in meal patterns, have not been adequately researched. Additionally, research examining whether the health benefits that marriage brings can be universally found for both genders across countries is limited. Family life events carry other consequences, too. Prior research also suggests that family life often has a negative impact on attitudes toward paid work, particularly for women. Past research, however, primarily relied on small sample interview data or cross-sectional data, leaving unclear how work attitudes change during adulthood. This dissertation examines the impact of different family life events such as marriage, cohabitation, and parenthood on changes in subjective well-being, health-related behavior (meal patterns), and attitudes towards work by gender. I focus on adults in their prime work and family life stages in the U.S. and Japan. By using fixed effects models and panel data, I aimed to estimate the average effect of family life events within individuals over time. I found that entering a romantic union reduces meal skipping, but the type of union matters differently for men and women. I also found that the transition to parenthood discourages women’s regular meal patterns, suggesting family ties do not necessarily facilitate healthy behaviors. In the highly gendered social context of Japan, contrary to previous findings from Western industrialized countries, I found no evidence indicating that marriage is associated with self-rated health for women. Additionally, I found that the transition to parenthood is negatively linked with men’s self-rated health. In terms of work attitudes, even when controlling for various job characteristics, I found that both marriage and parenthood are negatively associated with enthusiasm toward work achievement, only for women in Japan. These findings highlight the importance of country context and reveal that entry into marriage triggers shifts in women’s work attitudes even before having children.