Background: To address concerns that healthy weight and lifestyle campaigns (HWLCs) could have unintended psychological or behavioral consequences, this study tested reactions to TV advertisements from two HWLCs--"LiveLighter"® (employs graphic health effects messaging) and "Swap It Don't Stop It" (employs animation and light-hearted messaging). Methods: An online between-subjects experiment tested reactions to one of five advertisements: "Toxic Fat"; "Sugary Drinks" (both from "LiveLighter"); "Become a Swapper"; "How to Swap It" (both from "Swap It"); and "HSBC Bank" (control) among 2,208 adults from Western Australia and Victoria, Australia. Responses assessed were cognitive and emotional reactions, behavioral intentions, internalized weight bias, antifat attitudes, self-esteem and body dissatisfaction. Results: The HWLC advertisements prompted favorable cognitive reactions and weak to neutral positive and negative emotional responses. HWLC advertisements promoted stronger intentions to engage in adaptive lifestyle behaviors compared with the control advertisement. Intention to engage in maladaptive behaviors (e.g., skipping meals) was low overall and did not differ by condition. Compared with the control condition, participants who saw "LiveLighter" "Sugary Drinks" showed weaker disagreement with antifat attitudes; however, mean antifat attitude scores were still at the low end of the scale. HWLC advertisements did not promote internalized weight bias, reduced self-esteem or body dissatisfaction compared with the control advertisement. Conclusions: Overall, HWLC advertisements performed favorably compared with the control advertisement and showed no clear evidence of adverse impacts. Findings suggest HWLC advertisements may not promote negative psychological and behavioral consequences and can continue to be used in obesity prevention efforts.