This mildly sour, chewy bread is made with a lactic acid starter that contains strains of lactobacillus, a friendly type of bacteria that adds good microbes into the bakery staple. Sourdough may be the healthiest choice if diabetes is a concern for you. One 2008 study found that people with pre-diabetes who ate sourdough bread had less of a blood sugar spike as compared to when they are bread made with baker’s yeast. Experts also say fiber-rich whole grain bread can also reduce a post-meal blood sugar spike. Researchers credit the lactic acid for the favorable effect.