Obesity rates among children and young adults are considered one of the most consequential global public health challenges of the 21st century (Hurt et al., 2010; WHO, 2016). Obesity comorbidities include propensity of low self-esteem (Franklin et al, 2006). Using the Theory of Planned Behavior (TPB), a triangulation mixed-methods, quasi-experimental research design was implemented among college students who reported weight, height, and self-esteem both currently and retrospectively for middle school. Randomized cluster sampling method was utilized (n=185). Calculated BMI indicated 25.2% of participants were overweight or obese in middle school, which increased to 45.1% in college. Contrary to calculated BMI, 78.2% of participants described themselves as normal/underweight in middle school (n=140) and 69.1% in college (n=125). Current BMI was positively associated with middle school weight concerns and middle school BMI (p=0.01), and negatively associated with middle school self-esteem (p[less than or equal to]0.05). Subjective norm construct of TPB was most influential predictor of behavior. Thematic content analysis to qualitative inquiry of "if you could tell your middle school self one thing about your weight, what would you say?" Indicated affirmation themes of "love the skin you're in" and admonition themes of "stay active" and "portion control". Study implications for Generation Z are explored.