Objectives. We examined the effects of messages describing consequences of childhood obesity on public attitudes about obesity prevention policy. Methods. We collected data from 2 nationally representative Internet-based surveys. First, respondents (n = 444) evaluated the strength of 11 messages about obesity's consequences as reasons for government action. Second, we randomly assigned respondents (n = 2494) to a control group or to treatment groups shown messages about obesity consequences. We compared groups' attitudes toward obesity prevention, stratified by political ideology. Results. Respondents perceived a message about the health consequences of childhood obesity as the strongest rationale for government action; messages about military readiness, bullying, and health care costs were rated particularly strong by conservatives, moderates, and liberals, respectively. A message identifying the consequences of obesity on military readiness increased conservatives' perceptions of seriousness, endorsement of responsibility beyond the individual, and policy support, compared with a control condition. Conclusions. The public considers several consequences of childhood obesity as strong justification for obesity prevention policy. Activating new or unexpected values in framing a health message could raise the health issue's salience for particular subgroups of the public.