Carbohydrates, such as pasta and breads produce insulin in the blood stream, which in turn makes a chemical called tryptophan, which in turn produces serotonin. Serotonin puts the breaks on stress and tension and produces a calming effect.
When you eat some pasta for example, it calms your nerves and your mind becomes more focused. To achieve this effect, however, don’t combine these foods with protein-laden ones, because the process will be blocked.
If this is the case why are we Italians so high strung? We eat pasta or pizza virtually everyday. Imagine if we don’t get our pasta or pizza fix.