Obesity has reached epidemic proportions in the US, with a significantly higher fraction of African Americans who are obese than whites. Yet there is little understanding of why some individuals become obese while others do not. We conduct a lab-in-field experiment in a low-income African American community to investigate whether risk and time preferences play a role in the tendency to become obese. We examine the relationship between incentivized measures of risk and time preferences and weight status (BMI), and find that individuals who are more tolerant of risk are more likely to have a higher BMI. This result is driven by the most risk tolerant individuals. Patience is not independently statistically related to BMI in this sample, but those who are more risk averse and patient are less likely to be obese.