In Ramadan, Muslims perform a special kind of fasting. Their fasting start with the first lights of the sunrise and end with the sunset. Especially in summer, it is a real challenge, as the time for fasting might be as long as 18 hours, and hot weather might cause severe dehydration. This might be dangerous, especially in patients with diabetes. Serum osmolarity is a good surrogate marker to evaluate the body's fluid content. We aimed to investigate if summertime Ramadan fasting causes further fluid loss in patients with type 2 diabetes.

Till recently, it was assumed that patients with type 2 diabetes have to eat frequently, especially to avoid hypoglycemia, which is still true if they are using sulphonylurea or insulin. Especially because patients with diabetes often have one or more diabetic complications, they were advised against Ramadan fasting, as it is not allowed to eat or drink anything for long hours. There are increasing data supporting intermittent fasting, where individuals won't eat anything for 12-18 hours but are permitted to drink sugar-free beverages. The new antihypoglycemic agents have the advantage of causing very low or no hypoglycemia, which allows these patients to eat less frequently. There are studies about the metabolic effect of intermittent fasting in patients with type 2 diabetes, but we don't have enough data for the safety of religious fasting where no kind of fluid intake is allowed. In this study, we aimed to investigate the effect of fasting on the fluid status of diabetic patients. To this effect, we used serum osmolarity to determine fluid status. The patients who preferred to fast were our study group, and the patients who were healthy otherwise but preferred not to fast were our control group. In Ramadan, contrary to the customary practice of intermittent fasting, fasting starts with the sunrise and continues till sunset. We planned to take the first blood sample at 10 am and the second blood sample at 06 pm in both groups and compare the serum osmolarity accordingly.

Inclusion Criteria:

• patients with type 2 diabetes
• will accept to give two different blood samples
• will prefer to fast during Ramadan ( for the intervention group)
• will prefer not to fast during Ramadan ( for the control group)
• have good glycemic control

Exclusion Criteria:

• if the patients are not eligible for fasting

Outpatients who were attending to the clinics of diabetes in a medical faculty