The purpose of this study is to determine the variability in glycemic index determinations for individual foods and food combinations. The study will also evaluate the changes in insulin and free fatty acid levels, plasma lipid and lipoprotein profiles, C-reactive protein-a marker of inflammation and glycosylated hemoglobin- a marker of glucose metabolism during a five-hour period after eating the food or foods. Additionally, supplementary data on variation in oral sensation, habitual food intake, food preferences and genes mediating sensory perception and dietary behaviors (supported by a grant from the Tufts Ross Aging Initiative) will be related to the outcomes on the present study.
Inclusion Criteria: * For Phase 1 (Study 1) a total of seventy five volunteers will be included in the study. This study will be conducted in adult men and women (18-85 y) free of known chronic disease with BMI 18 to 35 kg/m2. * For Phase 2 (Studies 2, 3, 4, and 5) a total of 80 volunteers will be included, 20 volunteers per study. Phase 2 studies will be conducted in adult men and women (50 - 85 y) free of known chronic disease and with a BMI of 25 to 35 kg/m2. * For Phase 3 (Study 6) a total of 20 volunteers will be included in the study. Phase 3 study will be conducted in adult men and women (50-85 y) free of known chronic disease and with a BMI of 25 to 35 kg/m2. Exclusion criteria: * BMI ≥ 35 kg/m2 for Phase I, and BMI ≤ 25 to ≥ 35 kg/m2 for Phase II and III * Renal disease, as defined by a history of chronic kidney disease or by glomerular filtration rate of \< 60 ml.min/1.73 m2 calculated from screening blood tests. * Liver disease, as defined by a history of chronic hepatitis B or C, cholestatic or cirrhotic liver disease, nonalcoholic fatty liver disease, elevations of serum glutamate pyruvate transaminase (SGPT) or serum glutamate oxaloacetate transaminase (SGOT) greater than 1.5 times the upper limit of normal at screening, bilirubin greater than 2 mg/dL (in the absence of benign causes of elevated bilirubin such as Gilbert's syndrome) at screening, or albumin below the lower limit of normal. * Untreated hypertension, defined as systolic blood pressure (SBP) \> 140 mm and diastolic blood pressure (DBP) \> 90 mm. * Irritable bowel syndrome. * Malabsorptive disorder and inflammatory bowel disease. * Disorders of esophageal and gastrointestinal motility, and previous esophageal or gastric resection. * History of chronic pancreatitis, or history of acute pancreatitis within the last year. * Hypothyroidism or hyperthyroidism, as defined as screening thyroid-stimulating hormone (TSH) outside of normal ranges. * Anemia, as defined by screening hematocrit of 34% for women and 38% for men. * Smoking within the past 6 months. * Diabetes. * Fasting glucose ≥ 125 mg/dL. * Pregnancy. * Breastfeeding. * History of polycystic ovary syndrome * History of autoimmune or other connective tissue disorders associated with chronic inflammation, such as rheumatoid arthritis. * Alcohol consumption \> 7 drinks/week. * Use of medications or supplements known to affect glucose metabolism. * Use of medications or supplements known to affect lipid metabolism. * Established cardiovascular disease (myocardial infarction, stroke, heart failure, coronary artery. bypass graft, stenosis \> 50%, peripheral arterial disease). * Unwillingness to adhere to study protocol. * Weight gain or loss of more than 15 lbs within 6 months prior to enrollment.