The glycemic index measures the amount of blood glucose carbohydrate-containing foods produce. The more glucose produced, the higher the glycemic index. The GI's measurement standard is white bread, which has a GI of 100. A study in "Diabetes Care" notes that white bread is highly associated with diabetes. It suggests a change of bread with a lower GI (a score under 55 is considered low) may reduce the risk of diabetes and assist with weight loss.
Pumpernickel bread is made from coarsely ground rye flour with a sourdough starter to aid in rising. The ascetic acid produced by the sourdough starter and the soluble fiber of the rye flour give pumpernickel its low GI. When choosing a pumpernickel loaf, look for a German bread and whole rye kernels on the label. A traditional loaf may have a GI of about 46, according to GIListing.com.
Whole Grain Bread
A 100 percent whole-grain bread has a GI of about 51. Eat Right Ontario names this bread as being associated with lower risks of diabetes, cancer, heart disease and stroke. Whole grain bread consists of the endosperm, or inner seed, the bran that envelops the grain and the germ that feeds the seed. Fully whole-grain breads also contain phytonutrients such as antioxidants, and may help in weight management.
The University of Guelph cites a study that compared four different breads and the effect each have on carbohydrate metabolism, insulin levels and blood glucose. Sourdough bread showed the most positive responses. The researchers heading the study believe the benefits of sourdough bread arise from the fermentation of the sour starter. The GI is about 54 for sourdough bread, although breads made using only a percentage of sourdough might have a higher GI.
Opt for barley bread for a hearty addition to a low-GI diet. A serving of coarse bread made with whole barley grains has a glycemic index of just 30, and contains just 7 grams of carbohydrates. The whole barley kernels found in the bread also offer nutritional value, boosting your intake of magnesium and phosphorus, two minerals that nourish your bones.