Researchers at the University of Guelph tested four types of bread to ascertain the effects on blood sugar levels. Using white, whole wheat, whole wheat with barley and sourdough white breads, the team of researchers examined how subjects responded hours after eating the bread for breakfast and again just hours after eating a standard lunch. The subjects, who were overweight and ranged between fifty and sixty years of age, showed the most positive blood sugar responses after eating sourdough white bread. With the sourdough, the subject’s blood sugar levels were lower for a similar rise in blood insulin, and the positive effect remained during and after the second meal. What’s really interesting about this study is that the whole wheat breads—supposedly full of fiber that controls blood sugar levels—had the worst effects, causing blood sugar levels to spike, and these high levels lasted until well after lunch. Professor Terry Graham, head of the study, suggested that the poor response from the whole wheat bread was due to the milling process; but an equally likely explanation is the many anti-nutrients in whole grains that cause a stressful rise in blood sugar. These irritating and difficult-to-digest compounds are neutralized by the sourdough process. The team will soon be testing sourdough whole grain bread.