Greenopedia is one of many websites that provide a chart of alkaline and acidic foods. This website categorizes food as highly alkaline/acidic, moderately alkaline/acidic, low alkaline/acidic and very low alkaline/acidic.
AcidAlkalineDiet.net takes a different approach to the alkaline and acidic food chart. It categorizes specific foods into 10 different food groups and lists a corresponding potential renal acid load, or PRAL, score for each food. A negative score indicates that the food is alkaline and a positive score indicates an acidic food. The PRAL score is based on a 100 gram serving of the food, and the further the score is from zero in either direction indicates the degree of alkaline or acidity. AcidAlkalineDiet.net also provides two food combination reference charts.