When humans make decisions, objective rewards are mainly discounted by delay, risk and effort. Whereas recentresearch has demonstrated that several brain areas process costs and code subjective value in effort-based decisionmaking, it remains obscure how neural activity patterns change when effort costs are reduced due to theacquisition of healthy habits, such as moving from sedentary to active lifestyles. Here, a sample of sedentaryvolunteers was behaviorally assessed and fMRI-scanned before and after completing a 3-monthfitness plan. Theimpact of effort cost on decisions, measured as the constant defining a hyperbolic decaying function, was reducedafter the plan. A logistic mixed model demonstrated that the explanatory power of effort decreased with time. At aneural level, there was a marginally significant disruption of effort-cost related functional activity in the anteriorcingulate after the plan. Functional connectivity between the amygdala and anterior cingulate cortex wasstrengthened after habit acquisition. In turn, this interaction was stronger in those participants with lower effortdiscounting. Thus, we show for thefirst time changes in value-based decision making after moving from asedentary to an active lifestyle, which points to the relevance of the amygdala-cingulate interplay when theimpact of effort on decisions fades away.