Role of Slowly Digesible Starch on Diabetes Risk Factors

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.

Inclusion Criteria

- Have a body mass index between 30 and 44.9 kg/m2

- Are 35-65 years of age

- Have pre-diabetes, which means impaired fasting glucose (IFG)

- Are willing to complete nutritional and activity questionnaires and 2-3 weeks of
baseline testing

- Are willing to enroll in the 3-month intervention and maintain the same level of
exercise during the study

- Are willing to maintain weight throughout the study

Exclusion Criteria

- Have evidence of cardiovascular disease, diabetes, symptomatic cholelithiasis
(gallstones), or cancer

- Have a fasting blood glucose less than 100 mg/dL or greater than 125 mg/dL

- Have an average screening blood pressure > 150/100 mm Hg

- Are a pre-menopausal woman but do not have a regular menstrual cycle

- Are pregnant or breastfeeding

- Chronically use medications including diuretics, steroids, and adrenergic-stimulating
agents

- Have emotional problems such as clinical depression or other diagnosed psychological
conditions

- Use hormonal contraceptives, oral or parenteral glucocorticoids, or any other
medication known to influence glucose or insulin homeostasis (balance), within 1 month
of study

- Have a clinically significant gastrointestinal malabsorption syndrome, chronic
diarrhea, or use antibiotics within one month of study

- Have abnormal laboratory markers (e.g., elevated potassium levels, hemoglobin or
hematocrit below the lower limit of normal)

- Chronically consume alcohol (> 4 servings per day) or actively smoke cigarettes (> 1/4
pack per day)

- Are on any chronic medication that has not had a stable dose for 1 month or longer

- Are required to perform of any kind of heavy physical activity

- Have metal objects in the body, such as a pacemaker, metal pins, bullet, etc.