We all love Thanksgiving for the release of serotonin that comes from eating turkey, which is loaded with tryptophan. Extra tryptophan in your diet leads to extra serotonin in your brain, which is why tryptophan supplements are touted as a sleep aid and mood lifter (among other things). Foods that provide tryptophan include roasted white turkey, ground beef, cottage cheese, chicken thighs, eggnog, milk, and almonds.