When you’re on an endorphin high, you’re less likely to resist tempting food, a research study shows.

Happy people make healthier dietary decisions in general, but if you’re too excited, that happy/healthy link loses its oomph.

In one study, one group watched a positive but calm movie clip while another group watched a positive but arousing clip. Then they were both given the choice between a snack of grapes or M&M’s.

The ones who watched the action-packed clip were more likely to choose M&M’s, and the ones in the calm clip group who did choose M&M’s were more likely to monitor the amount they ate.

Exercise, which releases endorphins, was added to the routine. Everyone watched the calm clip, but some did a little exercise while some were sedentary.

The ones who exercised were more likely to choose the M&M’s.

The conclusion? It’s the shortage of mental energy that leads to less healthy choices.