Rye contains less gluten than wheat flour, and this makes rye bread significantly denser. Bread made from rye flour has a slightly sour taste when compared to wheat bread. Flour made from rye is often combined with wheat flour to make a lighter style of rye bread.
Rye is unique among grains for having a high level of fiber in its endosperm – not just in its bran. As such, the glycemic index of rye products is generally lower than products made from wheat and most other grains.