Fasting is a fundamental practice that shapes not only physical health behaviours but also spiritual meaning, moral emotions, and decision-making among people living with chronic diseases. This study examined how legal, cultural, and religious rulings on fasting are associated with health-related knowledge, attitudes, perceptions, and behavioural practices among patients with chronic conditions and their households in Saudi Arabia. A cross-sectional online survey was conducted with 1,033 respondents. A researcher-developed questionnaire assessed demographic characteristics, knowledge of obesity, diabetes, and hypertension, attitudes toward fasting (including health benefits and guilt about breaking the fast), perceptions of Islamic rulings on fasting during illness, lifestyle habits, and practices related to fasting. Descriptive statistics and ordinal logistic regression were used to identify predictors of higher knowledge and healthier practices. Approximately half of the participants demonstrated moderate knowledge of the clinical effects of fasting on chronic conditions, and about one-third had a positive attitude toward fasting, despite the disease exemptions in Islamic law. Knowledge of the rulings was consistently associated with higher health knowledge, more favourable perceptions of the exemptions, and better behavioural practices during fasting. Older age, female gender, poorer health and single marital status were also associated with more positive orientations toward health-promoting behaviours. These findings highlight the complex interplay between obligation, spiritual conscience, and clinical risk in fasting decisions. Strengthening collaboration between healthcare professionals and scholars may support spiritually sensitive counselling that aligns fiqh-based rulings with evidence-based care for chronic diseases and reduce spiritual distress and health risks for fasting with chronic diseases.
