Using a nationally representative sample of more than 2,800 U.S. adults between 21 and 90 years of age, we collect data about individual time preferences using a choice about whether to take some hypothetical lottery winnings as a series of payments over time or as a smaller lump sum now. We model individual financial discount rates as a function of age, other socio-demographic variables and variables to capture health expectations. Higher fitted discount rates at subjects’ current ages are generally associated with poorer current health-related behaviors for younger subjects. For older subjects, these undesirable current health behaviors are better predicted by their back-casted discount rates at age 21. Assuming cohort effects are minimal, we infer that changing time preferences as people mature can lead to the development of health habits while they are young that are likely to be inconsistent with the preferences of their older future selves.