Brain Regulation of Appetite in Twins

Inclusion Criteria:

- Ability and willingness to come with their twin to the University of Washington
(Seattle)

- Additional Criteria for Aim 1 random sample only: Member of randomly selected MZ pair
or

- Additional criteria for Aim 2 random sample only: One member of MZ or same-sex DZ pair
with BMI of at least 30 kg/m^2

- Additional criteria for Aim 3 sample only: Member of randomly selected MZ pair, and
not BMI discordant ≥ 5 kg/m^2

Exclusion Criteria:

- History of weight loss surgery or active participation in weight loss program

- Major medical problem (e.g., diabetes, cancer)

- Current use of weight loss medications or other medications known to alter appetite

- Pregnancy or menopause

- MRI contraindication (i.e., implanted metal, claustrophobia)

- Lifetime eating disorder

- Current smoking

- Current heavy alcohol use (≥2 drinks per day for females and ≥ 3 drinks per day for
males)

- Self-reported weight >330 pounds at time of phone screening. MRI cannot accommodate
all shapes or weights. Inability to have MRI does not exclude subject from
participating in other study procedures.

- BMI < 18.5 or > 45 kg/m^2

- Allergies to study foods or inability to taste

- Twins were raised apart

- Co-twin not eligible or not willing to participate