In a small study, researchers assigned 15 people to four different types of 100% whole grain bread and measured their blood sugar responses (using iAUC, post-meal glucose, and 3-hour glucose). One bread was made with 100% stone ground flour, one was made with 100% roller milled flour, one was made with 50% roller milled flour and 50% cracked whole wheat, and one was made with 40% roller milled flour, 30% intact whole wheat, and 30% cracked whole wheat — although all breads were 100% whole grain. Among the roller milled breads, they found that the larger the particle sizes in the bread (intact whole wheat > cracked whole wheat > roller milled wheat), the gentler the impact on blood sugar. Interestingly, the blood sugar response of the stoneground bread (as measured by iAUC) was better than the 50% cracked wheat / 50% roller milled bread, but not quite as good as the 40% roller milled / 30% intact whole wheat / cracked whole wheat bread.
Diabetes Care. 2019 Nov 19. pii: dc191466. doi: 10.2337/dc19-1466. (Reynolds AN et al.)
