In a double blind randomized controlled clinical trial, the investigators will test the effect of slowly digesting starch (amylose) versus a placebo starch (amylopectin) on risk factors for type 2 diabetes. For the study, about 95 obese participants (ages 35-65) with pre-diabetes (impaired fasting glucose) will consume a yogurt containing about 45 g of either the experimental or placebo starch daily for 3 months. The investigators will test the hypothesis that, compared to controls, a daily intake of 45 g of amylose for 3 months will improve risk factors for the development of type 2 diabetes (insulin sensitivity and secretion) by decreasing ectopic fat depots and decreasing inflammation in parallel with a change in colonic microbial populations.