Obesity is associated with increased risk for mortality, atherosclerotic cerebrovascular disease, coronary heart disease, colorectal cancer, hyperlipidemia, hypertension, gallbladder disease, and diabetes mellitus, resulting in over 111,000 deaths annually in the United States (Calle et al., 1999; Flegal et al., 2005). In the US, 65% of adults are overweight or obese (Hedley et al., 2004). Unfortunately, the treatment of choice for obesity (behavioral weight loss treatment) only results in a 10% reduction in body weight on average and most patients regain this weight within a few years (Jeffery et al., 2000). Further, most obesity prevention programs do not reduce risk for future weight gain (Stice, Shaw, & Marti, 2006). The limited success of treatment and prevention interventions may be due to an incomplete understanding of the processes that increase risk for obesity. Recent data suggest that obese adults show abnormalities in reward from food intake and anticipated food intake relative to lean adults, but the precise nature of these abnormalities is unclear and it has not been established whether these abnormalities predate obesity onset or are a consequence. It is vital to elucidate risk factors for obesity onset to advance understanding of etiological processes and determine the content of prevention and treatment programs.

The goals of this study are to (1) determine whether adolescents at high-risk for obesity, by virtue of having two obese parents, show abnormalities in reward from food intake (consummatory food reward) and anticipated reward from food intake (anticipatory food reward) compared to adolescents who are at low-risk for obesity, (2) determine whether abnormalities in consummatory and anticipatory food reward increase risk for weight gain and obesity onset, (3) examine moderators that may amplify the relations of consummatory and anticipatory food reward to unhealthy weight gain, and (4) examine changes in consummatory and anticipatory food reward in those participants who show obesity onset relative to those not showing obesity onset.

Inclusion Criteria:

• Between 14-17 years old
• BMI between 25th and 75th percentile

Exclusion Criteria:

• Contraindicators of functional magnetic resonance imaging (fMRI): metal implants, braces, pregnancy
• Symptoms of major psychiatric disorders (substance use disorders, conduct disorder, attention deficit hyperactive disorder, major depression, bipolar disorder, panic disorder, agoraphobia, generalized anxiety disorder) binge eating
• Current use of pyschoactive drugs
• Serious medical conditions (diabetes, brain injury)
• Current smoking
• Relevant food allergies
• Current weight loss dieting

162 lean adolescents between 14-17 years old with BMIs between the 25th and 75th percentile at baseline