Association Between Attitude Toward a Healthy Lifestyle, Lifestyle Behaviors, Sociodemographic Characteristics, and Body Mass Index: A Cross-Sectional Study

Background/Objectives: Healthy lifestyle behaviors are major contributors to overall health and disease prevention. This cross-sectional study aimed to assess attitude toward a healthy lifestyle and its associations with lifestyle behaviors, body mass index (BMI), excess body weight, sociodemographic characteristics, and self-rated health in adults. Methods: The Attitudes toward a Healthy Lifestyle Questionnaire was administered to 570 Croatian adults between November and December 2025. Multiple linear and binary logistic regression models were used to examine associations between lifestyle behaviors (number of daily meals, sitting time, sleep duration), smoking and e-cigarette use, alcohol consumption, BMI, self-rated health, and attitude toward a healthy lifestyle. Results: The median attitude toward a healthy lifestyle score was 52.0 (IQR = 10), corresponding to 62% of the maximum possible score. A more positive attitude toward a healthy lifestyle was associated with a higher number of daily meals (β = 0.16, p = 0.001), longer sleep duration (β = 0.17, p < 0.001), lower sitting time (β = −0.11, p = 0.010), and lower BMI (β = −0.24, p < 0.001). Smoking was negatively associated with attitude toward a healthy lifestyle (β = −0.18; p < 0.001), while e-cigarette use was associated with fewer daily meals (β = −0.10; p = 0.025). Longer sleep duration increased the odds of excellent self-rated health (OR = 1.31, p = 0.014), and a more positive attitude toward a healthy lifestyle was associated with lower odds of excess body weight (OR = 0.92, p < 0.001). Conclusions: Attitude toward a healthy lifestyle is significantly associated with lifestyle behaviors, BMI, excess body weight, and self-rated health, highlighting the importance of psychological factors in promoting sustainable healthy lifestyles.