Nutrition and healthy eating

Definition

A clear liquid diet consists of clear liquids — such as water, broth and plain gelatin — that are easily digested and leave no undigested residue in your intestinal tract. Your doctor may prescribe a clear liquid diet before certain medical procedures or if you have certain digestive problems. Because a clear liquid diet can't provide you with adequate calories and nutrients, it shouldn't be continued for more than a few days.

Clear liquids and foods may be colored so long as you are able to see through them. Foods can be considered liquid if they partly or completely melt to liquid at room temperature. You can't eat solid food while on a clear liquid diet.

Purpose

A clear liquid diet is often used before tests, procedures or surgeries that require no food in your stomach or intestines, such as before colonoscopy. It may also be recommended as a short-term diet if you have certain digestive problems, such as nausea, vomiting or diarrhea, or after certain types of surgery.

Diet details

A clear liquid diet helps maintain adequate hydration, provides some important electrolytes, such as sodium and potassium, and gives some energy at a time when a full diet isn't possible or recommended.

The following foods are generally allowed in a clear liquid diet:

• Water (plain, carbonated or flavored)
• Fruit juices without pulp, such as apple or white grape juice
• Fruit-flavored beverages, such as fruit punch or lemonade
• Carbonated drinks, including dark sodas (cola and root beer)
• Gelatin
• Tea or coffee without milk or cream
• Strained tomato or vegetable juice
• Sports drinks
• Clear, fat-free broth (bouillon or consomme)
• Honey or sugar
• Hard candy, such as lemon drops or peppermint rounds
• Ice pops without milk, bits of fruit, seeds or nuts

Depending on your medical condition, your physician or dietitian may alter the above list. For certain tests, such as colon exams, your doctor may ask you to avoid liquids or gelatin with red coloring. Any foods not on the above list should be avoided.

A typical menu on the clear liquid diet may look like this.

Breakfast

• 1 glass pulp-free fruit juice
• 1 bowl gelatin
• 1 cup of coffee or tea, without dairy products
• Sugar or honey, if desired

Snack

• 1 glass fruit juice (pulp-free)
• 1 bowl gelatin

Lunch

• 1 glass pulp-free fruit juice
• 1 glass water
• 1 cup broth
• 1 bowl gelatin

Snack

• 1 pulp-free ice pop
• 1 cup coffee or tea, without dairy products, or a soft drink
• Sugar or honey if desired

Dinner

• 1 cup pulp-free juice or water
• 1 cup broth
• 1 bowl gelatin
• 1 cup coffee or tea, without dairy products
• Sugar or honey, if desired

Results

Although the clear liquid diet may not be very exciting, it does fulfill its purpose. It's designed to keep your stomach and intestines clear and to limit strain to your digestive system while keeping your body hydrated.

Risks

Because a clear liquid diet can't provide you with adequate calories and nutrients, it shouldn't be used for more than a few days. Only use the clear liquid diet as directed by your doctor.

If your doctor prescribes a clear liquid diet before a medical test, be sure to follow the diet instructions exactly. If you don't follow the diet exactly, you risk an inaccurate test and may have to reschedule the procedure for another time.

If you have diabetes, talk with your doctor, dietitian or diabetes educator. A clear liquid diet should consist of clear liquids that provide approximately 200 grams of carbohydrate spread equally throughout the day to help manage blood sugar (blood glucose). Blood sugar levels should be monitored and the transition to solid foods should be done as quickly as possible.