Apolipoprotein E (ApoE) and Metabolism

The investigator will measure the amount of oxygen participants breathe in and the amount of carbon dioxide they breathe out using a portable unit. Participants will be asked wearing a loose-fitting face mask that measures oxygen intake and carbon dioxide output.

The investigator will conduct a genetic test on DNA isolated from from the participants blood. Participants will be asked to provide about 2 tablespoons.

To more accurately measure the amount of carbohydrates, fats and proteins that the participants bodies metabolize, participants will be asked to provide two urine samples (one at the beginning, and one at the end, of the study). The total amount of urine to be collected is approximately 4 teaspoons.

Participants will be asked to follow simple instructions that are displayed on computer screen.