Not eating for eight to 12 hours before having blood drawn for a cholesterol test was thought to give a more accurate assessment of total cholesterol, harmful LDL cholesterol, protective HDL cholesterol, and triglycerides, a type of fat-carrying particle. You can drink water in small amounts but only have it in small amounts as it will stimulate hormones which can effect cholesterol levels.

Blood cholesterol levels vary in their levels in blood according to the diet we take. To maintain uniformity and to draw any meaningful conclusions, lipid profile is done in a fasting state. Yes, you can have little water if you are very thirsty. Try not to take too much as again it stimulates gut hormones which can effect cholesterol levels.