The production of healthy offspring depends on many factors spanning from intrinsic genetic elements to variations in the in utero environment. Poor maternal diet is associated with increased risk of cardiovascular, metabolic and behavioural disorders during later life of the offspring, but how the developing embryo copes with maternal dietary stress has not been well characterised. Now, on p. 1140, Tom Fleming and colleagues investigate the compensatory mechanisms that are activated when the early embryo is challenged by poor maternal nutrition. Using quantitative imaging techniques and extensive marker analyses, the authors show that a restricted-protein maternal diet results in stimulated endocytosis within both the trophectoderm and the primitive endoderm of the early mouse embryo to overcome the shortfall in nutrient supply. The authors show that enhanced trophectoderm endocytosis occurs in response to reduced branched-chain amino acids and is mediated via RhoA GTPase signalling. This exciting finding is an important step in uncovering the cellular mechanisms that underpin disorders caused by poor maternal nutrition.