**Background:** Overweight and obesity affect over 1.9 billion adults and nearly 400 million children globally, and are major risk factors for non-communicable diseases including type 2 diabetes, cardiovascular disease, and certain cancers. While previous research has shown associations between parental obesity and childhood obesity, few studies have examined family-level obesity across multiple countries with diverse socioeconomic settings. This study aimed to report the prevalence of family obesity and examine its associations with socio-demographic characteristics and lifestyle factors using baseline data from the Feel4Diabetes study across six European countries.
**Methods:** The Feel4Diabetes study was a large-scale community-based, family-involved intervention conducted in Belgium, Bulgaria, Finland, Greece, Hungary, and Spain during 2016-2018. Recruitment targeted families from low socioeconomic areas, with primary schools serving as entry points. Children had to be in the first three grades of compulsory education. Data were collected at baseline (2016) by rigorously trained researchers using standardized procedures. Anthropometric measurements (height and weight) were taken using calibrated equipment, and BMI was calculated according to WHO classification. Family obesity was defined as obesity in at least two of three family members (both parents or child and any parent). Socio-demographic information was collected via self-reported questionnaires. Dietary intake was assessed using a Food Frequency Questionnaire covering water, fruits, vegetables, dairy, cereals, soft drinks, sweets, savoury snacks, fast food, and breakfast frequency. Physical activity and screen time were subjectively measured. Countries were classified economically as "low-income" (Bulgaria, Hungary), "under austerity measures" (Greece, Spain), and "high-income" (Belgium, Finland). Statistical analyses included chi-squared tests, ANOVA/Kruskal-Wallis tests, and univariate and multivariate logistic regression with Bonferroni correction. A sample of 9,576 child-parent pairs with complete data was analyzed.
**Key Results:** Overall, 6.6% (n=628) of participating families had obesity. Family obesity prevalence was highest in countries under austerity measures (7.6%; n=244/3192), followed by low-income countries (7.0%; n=270/3850), and lowest in high-income countries (4.5%; n=114/2534) (p<0.001). By country, Greece had the highest prevalence (9.2%; n=168/1826), followed by Hungary (8.6%; n=123/1437), Bulgaria (6.1%; n=147/2413), Finland (6.0%; n=62/1029), Spain (5.6%; n=76/1366), and Belgium (3.5%; n=52/1505). The combination of one obese parent with an obese child was significantly higher in low-income countries (3.4%) and countries under austerity measures (3.4%) compared to high-income countries (1.3%) (p<0.001). In multivariate analyses, higher paternal education (>14 years vs. <9 years) was associated with significantly lower odds of family obesity in the total sample (OR 0.37, 95% CI 0.24-0.59), in low-income countries (OR 0.24, 95% CI 0.10-0.54), and in countries under austerity measures (OR 0.39, 95% CI 0.17-0.86). Maternal full-time employment was associated with lower odds in high-income countries (OR 0.55, 95% CI 0.31-0.98). Regarding lifestyle factors, each additional cup of water consumed per day was associated with increased odds of family obesity in the total sample (OR 1.11, 95% CI 1.06-1.15), in low-income countries (OR 1.06, 95% CI 1.01-1.12), and in countries under austerity measures (OR 1.24, 95% CI 1.12-1.37). Each additional day per week of meeting physical activity recommendations was associated with reduced odds in the total sample (OR 0.95, 95% CI 0.92-0.98), in low-income countries (OR 0.95, 95% CI 0.90-0.99), and in countries under austerity measures (OR 0.91, 95% CI 0.86-0.97). Savoury snack consumption was associated with increased odds in the total sample (OR 1.14, 95% CI 1.01-1.28). Interestingly, sweets consumption was associated with reduced odds in the total sample (OR 0.87, 95% CI 0.78-0.97) and in low-income countries (OR 0.92, 95% CI 0.81-1.05, not significant).
**Clinical Implications:** This study demonstrates that family obesity is a significant public health issue across Europe, with approximately one in fifteen families affected, and substantially higher rates in countries under economic austerity. The strong associations with lower parental education and unemployment suggest that socioeconomic factors are critical determinants of family obesity risk. Clinicians should adopt family-based approaches to obesity prevention and treatment rather than targeting individuals, and should be aware that families with older parents, lower educational attainment, and unemployment may be at highest risk. Interventions should promote regular breakfast consumption, increased physical activity, and reduced consumption of processed foods including savoury snacks and soft drinks. The variation in risk factors across different economic contexts suggests that tailored, country-specific public health strategies may be more effective than one-size-fits-all approaches. Future research should explore causal mechanisms underlying these associations to better inform European and national public health policy.