Two Pathways to Glycaemic Control: Dietary Adherence, Physical Activity, and Their Independent Contributions Among Persons with Type 2 Diabetes in Urban Delhi—A Community-Based Cross-Sectional Analytical Study

Background: India bears one of the highest diabetes burdens globally, yet community-based evidence simultaneously examining the contributions of dietary adherence and physical activity to glycaemic control remains scarce. Most existing Indian studies are hospital-based and assess only one behavioural domain. Methods: A community-based cross-sectional analytical study was conducted among 320 persons with type 2 diabetes in Gokulpuri, North-East Delhi. Dietary adherence was assessed using the Perceived Dietary Adherence Questionnaire (PDAQ) and physical activity using the International Physical Activity Questionnaire (IPAQ). Glycaemic control was measured as random blood sugar (RBS). Sociodemographic and clinical determinants of each behavioural domain were examined using bivariate analyses, followed by multivariable linear regression. Three nested multiple linear regression models were estimated to quantify the independent and combined contributions of dietary adherence and physical activity to RBS. Results: The mean age was 58.09 years (SD 11.17); 65.3% were female. Mean RBS was 217.41 mg/dL (SD 82.21), mean PDAQ score was 47.01 out of 63 (SD 5.32), and mean IPAQ was 531.67 MET-min/week (SD 526.54). Higher household income was a significant positive predictor of dietary adherence (β = 0.103, p = 0.009), while a positive family history of diabetes was a significant negative predictor (β = −2.203, p = 0.004). Male gender was the only significant predictor of greater physical activity (p < 0.001). In nested regression models adjusted for age, gender, education, BMI, diabetes duration, and hypertension, both dietary adherence (β = −3.117, p = 0.001) and physical activity (β = −0.026, p = 0.004) were independently and significantly associated with lower RBS. The combined model demonstrated the best fit (Adjusted R2 = 0.078, F = 3.62), with the two predictors showing near-zero mutual correlation (r = 0.008), confirming their independence. Conclusions: In this cross-sectional analysis, dietary adherence and physical activity were independent additive predictors of lower random blood sugar (RBS) in community-dwelling persons with type 2 diabetes in urban Delhi. Income and diabetes fatalism are key modifiable determinants of dietary adherence, while gender-based disparities drive differences in physical activity. Integrated, dual-domain lifestyle interventions addressing these sociodemographic barriers are warranted within community-based NCD programmes in India.