Patients with diabetes often have to take tests that require they eat a clear liquid diet the day before. Some tests that need this special diet include a colonoscopy, capsular endoscopy, and certain surgeries. Doctors recommend the clear liquid diet before a procedure because this type of food is very easy to digest. This means the food will not block the doctor’s view of the important parts of the body. For people with diabetes, eating a clear liquid diet can be hard, because many of the allowed foods and drinks contain high amounts of sugar. It is important for someone with diabetes to have other choices besides the high-sugar foods usually recommended on a clear liquid diet.
Sugar-free foods that can be eaten on a clear liquid diet:
Water and flavored waters (carbonated waters are also okay)
Diet drinks like Diet Snapple™, Crystal Light™, PowerAde ZERO™, Skinny Water™, and Gatorade G2™ - Avoid red and purple colors
Coffee and teas without milk or creamer ; Can be iced or hot, unsweetened or artificially sweetened.
Sugar-free popsicles – Choose lighter colors like lemon
Sugar-free gelatin (Jell-O™) – Avoid flavors that are red or purple
Soup broths (must be low- or non-fat broth, bouillon and consommé are okay)
No matter what type of clear liquid diet you choose, make sure you check in with your doctor first. When diets change in a big way, anti-diabetic medications have to be adjusted, too. For instance, medications like insulin and pills called sulfonylureas can become very dangerous when a person is eating much less than normal. Also, for surgeries that may require hospitalizations, other diabetic medications like metformin and SGLT-2 inhibitors are not to be taken for at least 24 hours before the procedure.
A colonoscopy is probably the most common reason for a clear liquid diet. That test also includes a preparation to help wash out the system so the doctor can view the colon better. Before the procedure, be sure to tell the doctor about medical problems, including diabetes. It is important for those with diabetes to know that the commonly used preparations GoLYTELY™, NuLYTELY™, and HalfLYTELY™ contain no added sugars.
For some procedures, the patient is usually NPO (nothing to eat at all). This will affect medications doses as well. Be aware that patients do not usually eat after they wake up from sedation until much later in the day. Again, having a plan from your doctor ahead of time can help avoid problems like low blood sugars.
Because a clear liquid diet of sugar-free foods contains little to no calories, be sure to get your doctor’s okay before starting the diet. Not only will medications need adjusting, but these types of foods are only safe for very short periods of time. Clear liquids, especially those that are sugar-free, do not have enough nutrition to provide the energy needed for daily life.
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