There is a body of scientific evidence that supports a role for yoga in diabetes control and management. Let me present a summary of the scientific support available in the literature:
A systematic review of articles and studies on Yoga’s health impact shows that its practice helps in weight control, reduction of blood pressure, blood lipids, and blood sugar. (Yang, K., 2007; Youngwanichsetha, S. et al., 2014)
Yoga and standard physical training exercises both have a positive impact on individuals who have diabetes. It helps reduce oxidative stress and bring about improvements in antioxidant profiles. (Gordon, L.A., et al., 2008)
Diabetic individuals who performed pranayama felt a sense of well-being in 7 to 10 days of practice. Demand for insulin, other diabetes control medicine dropped. In this trial, four pranayama types were practiced for 30 minutes, followed by 10 minutes of resting yoga posture called Shavasana (a dead person pose posture). (Sahay, B.K., 2007)
In addition to breathing exercises, eight forms of physical activities – (Yoga asana)- have been observed to benefit diabetic patients. These exercises were practiced each day for 45 minutes, followed by relaxation exercises like Shavasana (Deadman pose) and Makrasana (Crocodile pose).
The Yoga asana practiced were Dhanurasana (Bow Pose), Ardha matsayendrasana (half spinal twist) helped control diabetes optimally. Halasana (plow pose), Vajrasana (sitting posture with feet under your hips, Bhujangasana (Cobra pose), Naukasana (boat pose) were effective.
I have presented a summary on this subject here, but there is a lot more on this subject. You can find the details here.