Many people struggle with the classical choice of eating a mouth-watering snack versus a healthier product. One of the reasons behind this is that unhealthier products are appealing for their direct gratification; they deliver pleasure. The present research investigates the effect of mental simulation as a relatively new strategy to possibly shift the balance between direct gratification and the consideration of longer-term benefits necessary to make healthier choices. Specifically we distinguish between imagining the consumption process versus the outcome of eating a specific product, hereafter referred to as mental simulations. In two studies, we show that participants under process simulation, i.e., imagining the process of eating, had a higher desire for the imagined product compared to a control condition, but in a choice task between a healthy and an unhealthier product, more people chose the unhealthier product over the healthier one. On the other hand, outcome simulation, i.e., imagining the outcome of eating, also generated a higher desire for the imagined product, but in this case people chose the healthier option. In terms of underlying process, we explored the role of valence of the imagined experience on desire for the imagined product. This is the first study giving insights into the processes that could be behind the impact of mental simulation on desire and food choices. Although the results are not conclusive, we propose that further research in attentional biases, and possibly emotional activation could enlighten the effect of mental simulation in food desires and choice between healthy and unhealthy alternatives.