This study is designed to investigate associations of low- and high-glycemic load diets with biomarkers of hyperglycemia, hyperinsulinemia and inflammation, potential biomarkers for cancer risk.

This is a randomized, crossover feeding study conducted in normal weight and overweight individuals. Participants will be given all their food to eat and drink (except water) for two 28-day feeding periods (a total of 56 days). The diets will be carefully controlled and energy intake will be regulated to maintain weight stability for each participant. The two feeding periods will be separated by a 28 day "washout" period when participants will eat their own food. Dinner will be eaten at the Hutchinson Center Monday through Friday. Each evening, breakfast, lunch and snacks will be brought home for the next day. On Friday evenings all the food will be taken home for the weekend.

Samples of blood will be collected after an overnight fast at the beginning and the end of each feeding period. All urine will be collected for 24 hours at the end of each feeding period. A number of questionnaires will also be completed during each diet period. A small stool sample will be collected in your own home, before the first feeding period, and once during each feeding period. The stool sample collection is optional. One can decide not to provide a stool sample and still participate in the study.

Inclusion Criteria:

1. Healthy males and female subjects
2. Between the ages of 18 to 45
3. BMI between 18.5 kg/m2 to 24. 9 kg/m2 (normal weight) and between 28.0 kg/m2 to 39.9 kg/m2 (overweight)
4. Willingness to refrain from alcohol during the study
5. Able to come to the FHCRC in Seattle every weekday night for dinner

Exclusion Criteria:

1. Younger than 18 years of age or older than 45 years of age.
2. Do not fit into one of the study weight groups (normal weight and overweight): BMI < 18.5 kg/m2 or > 40.0 kg/m2, and between 25.0 kg/m2and 27.9 kg/m2
3. Have diseases that are treated by diet and/or medications including but not limited to diabetes, kidney disease, heart disease
4. Taking prescription medications every day (this includes women taking birth-control pills, shots, patch or IUD with hormones)
5. Diagnosed with or treated for cancer within the previous five years (except those with a diagnosis and/or treatment of non-melanomatous skin cancer are eligible)
6. Currently pregnant or breastfeeding or planning a pregnancy in the next 3 months.
7. Using any tobacco products on a daily basis (cigarettes, pipes, cigars, chewing tobacco).
8. Using recreational drugs
9. Drinking the following amount of alcohol almost every day: 2 or more cans/bottles of beer OR 2 or more glasses of wine OR 3 or more ounces of hard liquor.
10. Inability (e.g., food allergy or intolerances) or unwillingness to consume the foods that are part of the feeding study diet.