This could be because the body increases insulin secretion in anticipation that sugar will appear in the blood. When this doesn’t happen, blood sugar drops and hunger increases. Whether this chain of events regularly takes place is somewhat unclear. Something odd happened when I tested Pepsi Max though, and there are well-designed studies showing increased insulin when using artificial sweeteners.
Which is why it pays to keep your cool. One way to do so: practicing mindfulness. According to a 2011 Journal of Obesity study, women who experienced the greatest reduction in stress by effectively mastering stress-reduction techniques tended to lose the most deep belly fat. So go ahead and take some deep breaths, hit the mat for some anxiety-relieving yoga, or open up one of those guided-meditation apps. Your belly will thank you in the long run.