TikTok has gained immense popularity among teenagers, offering access to numerous user-generated content. Notably, food videos have emerged as a prominent theme on this short-form video social platform. The casual and enjoyable nature of short food videos on TikTok belies their potential influence on one of teenagers' most immediate and regular health practices--eating. Understanding how teenagers interact with these videos, their subsequent actions, and the resulting impact on their food practices and eating habits have the potential to provide insight into their broader lifestyle choices and their interactions within their social circles, including parents, friends, and other people online. By examining how teenagers use TikTok food videos online and offline, we gain a deeper understanding of the intricate relationship between social media, teenage lifestyle, and social dynamics surrounding food practices. In this research, we conducted 15 semi-structured interviews with teenagers aged 13 to 19, investigating their consumption of TikTok food videos and the actions inspired by them. By examining the multifaceted influence of TikTok food videos from a temporal perspective, this study contributes to the reflections of teens' use of TikTok food videos and their inspired food practices in the short and long term, online and offline. We propose design and theoretical implications to support teenagers' health. These insights have the potential to extend to various contexts, helping educators, policymakers, and designers in fostering healthy lifestyles among teenagers.