Meals rich in carbs or proteins on plasma tryptophan and tyrosine ratios
This is an important consideration. Tryptophan crosses the blood brain barrier to get converted to serotonin. Serotonin helps modulate sleep and mood and satiety (drugs like Prosac work to increase levels of serotonin by increasing the time it is able to affect nervous transmission). However, tryptophan has a harder time crossing the BBB with competition from other amino acids. So, paradoxically, foods with lots of protein will contain higher levels of trypthophan, but less of this actually makes it to the brain because of the competition from the other amino acids. Foods such as soybeans, bananas and beans have relatively high tryptophan levels can help to increase brain tryptophan. In addition, supplemental 5-HTP has been shown to increase brain serotonin levels as well.
AJCN — Abstracts: Wurtman et al. 77 (1): 128