This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
Rye may be said to stand very close to wheat in importance as a food. In Europe it is more in use for bread-making than in this country, where it is mainly eaten by the Germans. In Germany the rye production is double that of wheat, and in Russia it is three times greater. Former generations lived almost entirely upon rye in France, as they did upon oats in Scotland and parts of England, wheat being an almost unobtainable luxury.
Rye yields a coarser, darker bread than wheat, but is about equally nutritious, although not always so digestible, and it is somewhat laxative. In general, the statements made in the preceding pages (pp. 140-144) in regard to bread-making, etc., with wheaten flour, may be applied to rye flour.
Rye bread contains less gluten than wheaten bread, and it takes less time to raise and bake it, provided the oven is very hot. If properly made it is easily assimilated, and many like its taste.
Rye is often combined with wheat in France, under the name of meteil, and in Spain and Greece a mixture of the same name is made with barley instead of wheat.