It is very difficult to decide to what extent condiments and flavourings should be used. These have stimulating properties, although differing from the more complex properties of alcohol and the alkaloids. The great differences in the dietetic practices of nations does not appear to be in conformity with any general rule. It varies with opportunity, climate and national temperament; though doubtless the national temperament is often due in part to the dietetic habits....
Excerpt above from The Chemistry of Food and Nutrition, by A. W. Duncan