Neurotransmitters are sensitive chemical messengers that require just the right environment to trigger their release. Tryptophan is an amino acid in milk products that leads to a calm mood by increasing serotonin production, according to the University of Maryland Medical Center. It is known to help you relax and sleep better. Eating ice cream when you're stressed out, however, may negate any calming effect it may have. Tryptophan and serotonin that provide you with a sense of calm may not get triggered if you're placing stress on your body. Various medications and infections also may interfere with the production of those feel-good reactions.