The purpose of this study is to investigate the effect of low glycaemic diet on blood glucose control in Chinese type 2 diabetic patients.

Glycaemic index (GI) is the measurement of post-meal blood glucose rise cause by ingestion of carbohydrate. For the same amount of carbohydrate, food with lower GI value cause a lower post- meal rise in blood glucose concentration in both normal and diabetic patients. Meta-analysis of randomized controlled trial has showed that low GI diet can achieve an additional reduction of A1c by 0.4% when compare with usual diabetic diet. Furthermore, various diabetes associations have already endorsed the use of low GI diet in the management of diabetes.

Hong Kong Chinese obtain most of their carbohydrate intake through consumption of rice or rice related foods, which are considered as having high GI value. In addition, it has been demonstrated that Asian have higher post-prandial rise in blood glucose than Caucasian after consuming the same amount of carbohydrate. When the above two factors add together, we expect our local type 2 diabetic patients are suffering from significant post-prandial hyperglycaemia, which in turn translate into elevated 24-hour hyperglycaemia and A1c.

However, nearly all studies about glycaemic index and diabetes are conducted in Caucasian. It is unclear about the benefit in Chinese patients with type 2 diabetes who are currently having diet with high GI value.

We therefore hypothesized that low GI diet may improve blood glucose control in Chinese type 2 diabetic patients. To test this hypothesis, we plan to conduct this randomized controlled trial about low GI diet in Chinese diabetic patients.

Inclusion Criteria:

1. Chinese Type 2 diabetic patient.
2. Already performing self monitoring blood glucose ( SMBG ) with pre- and post-meal readings.
3. At least 50% of 2hr post-meal capillary blood glucose values are > 9 mmol/L.
4. A1c between 7.0 to 8.0% within 2 weeks of randomization.
5. Next follow-up is scheduled to at least 12 weeks or more if currently follow-up in TWEH.
6. On stable dose of anti-diabetic drug in the preceding 10 weeks.
7. No change in anti-DM drug in the next 10 week.
8. At least 18 years old.
9. Can read and understand consent form written in Chinese.
10. Can give informed consent.

Exclusion Criteria:

1. Unexplained hypoglycaemia in last 4 weeks.
2. Using rapid onset insulin ( such as Humalog, Novorapid, Actrapid HM, Mixtard HM, Novomix and Humalog Mix ).
3. Using acarbose.
4. Anaemia.
5. Known thalassaemia.
6. Suspected or confirmed iron deficiency.
7. On warfarin.
8. Renal impairment with serum creatinine > 150 umol/L
9. Active medical illness, such as hepatitis, malignancy, infection, inflammatory arthritis, etc.
10. Unable to follow low glycaemic index diet.
11. Currently participate in other study.
12. Mentally or cognitively disable.
13. Pregnant or lactating women.
14. Hospital Authority or TWEH staff.