Patterns of weight loss attempts and clinically significant weight loss among US adolescents and adults: analysis of NHANES 2021-2023.

Objective: Obesity remains a major public health challenge in the United States. We estimated the prevalence of weight loss attempts and clinically significant weight loss (CWL) among US adolescents and adults, and to assess associations with age, sex, race/ethnicity, and BMI. Methods: We analyzed National Health and Nutrition Examination Survey (NHANES) data collected from 2021 to 2023. The analytic sample included 6308 participants aged ≥16 years. We assessed past-year weight loss attempt (yes/no) and CWL (≥5 % and ≥10 %) using measured current weight and self-reported weight 1 year earlier. Weighted estimates accounted for NHANES complex sampling; multivariable logistic regression adjusted for age, sex, race/ethnicity, and BMI category. Results: 47.4 % reported attempting weight loss, with differences by age (P < 0.01), sex (P < 0.01), and BMI (P < 0.01), but not race/ethnicity (P = 0.22). Among those attempting weight loss, 28.2 % achieved ≥5 % while 12.9 % achieved ≥10 % weight loss. Adolescents showed the highest prevalence of achieving ≥10 % weight loss (15.8 %; P = 0.02). Overweight and obesity were strongly associated with attempts (adjusted odds ratios, aOR 3.20 and 6.60), and females had higher odds than males (aOR 1.96). Conclusions: While weight loss attempts are prevalent, CWL is achieved by a minority, demonstrating the need for effective, equitable obesity treatment and prevention strategies.