Is stress or poor sleep enough on its own to raise diabetes risk, even with a healthy diet?

They can be contributing factors, yes. Chronic stress and poor sleep both affect insulin sensitivity and blood sugar regulation through hormonal pathways (cortisol, disrupted glucose metabolism), independent of diet quality. They're not usually considered as strong a risk factor on their own as things like family history or age, but they're real, documented contributors that can meaningfully raise risk even layered on top of an otherwise reasonable diet. References: https://obesitycanada.ca/healthcare-professionals/adult-clinical-practice-guideline/ https://guidelines.diabetes.ca/GuideLines/media/Docs/Quick%20Reference%20Guide/2024-CPG-Quick-Reference-Guide.pdf