Developmental conditions including temperature, diet, and parasites can shape adult fitness phenotypes in many species. Studies typically focus on the additive effects of early-life and adult life conditions on life history response in the context of competing models of developmental plasticity (i.e. environmental matching and silver spoon). These models continue to yield mixed results in the same or different species. Here, we characterize interaction effects of larval vs adult diet on lifespan and fecundity in a high diversity outbred population of Drosophila melanogaster. We compare fitness proxies of matched vs mismatched early-to-late nutritional conditions differing in protein content. Diet interactions significantly affected both traits, albeit differently. We find no consistent evidence for either model. Rather, several patterns emerged including age and sex effects, survival differences in the post-median life phase, regime-specific timing of peak fecundity, and substantial fecundities in older post-median flies. We find that mild protein restriction increases both maximum lifespan of males and female lifetime fecundity. Surprisingly, lower adult protein delayed egg-laying by about 2 weeks, compared to treatments with higher protein in adult diet. This effect was particularly evident in treatments involving protein-restricted developmental diets. Our results highlight the need for assessing patterns of response over the course of life which can potentially reveal more subtle interacting processes compared to cross-sectional measurements. In addressing the impacts of environmental change in natural systems, it will be necessary to consider nuanced approaches that account for both, additive and interaction effects in diverse genetic backgrounds.