The Truth About Liquid Diet

What is Liquid Diet

A full liquid diet is made up only of fluids and foods that are normally liquid and foods that turn to liquid when they are at room temperature, like ice cream. It also includes:

• Strained creamy soups
• Tea
• Juice
• Jell-O
• Milkshakes
• Pudding
• Popsicles

Like the name suggests, liquid diets mean you’re getting all, or at least most, of your calories from drinks.

Some liquid diets are limited to fruit or vegetable juices, or shakes, that replace all of your meals, taken three or four times a day. You do some of these diets on your own. Others need medical supervision.

Other types of liquid diets replace just one or two meals (usually breakfast and lunch) with drinks, and then you eat a healthy dinner. You may also get snacks on some of these plans.

Clear liquid diet

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 ¹. 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 are even partly 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.

• Clear Liquid 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 allowed in a clear liquid diet:

• Water (plain, carbonated or flavored)
• Fruit juices without pulp, such as apple or white grape
• 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

Any foods not on the above list should be avoided. Also, for certain tests, such as colon exams, your doctor may ask you to avoid liquids or gelatin with red coloring.

• 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 as you prepare for or recover from a medical procedure.

• 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.

Do Liquid Diets Work ?

Liquid diets can work, like any diet that gives you fewer calories than you use.

But the results may not last. When you drastically cut calories, your metabolism slows to save energy. Unless you change your eating habits, you’re likely to regain the weight you lost after you go off the liquid diet.

Some liquid diets work better over the long term than others. Diets that include both solid food and liquids can help overweight people control the number of calories they eat and help keep the weight off for several years.

How Safe Are Liquid Diets ?

Ideally, liquid diet drinks should give you a balance of nutrients you need throughout the day, but that isn’t always the case.

Very low-calorie diets (400-800 calories per day) in particular can be lacking in nutrients and should only be used under medical supervision.

Missing out on essential nutrients can lead to side effects such as fatigue, dizziness, hair loss, gallstones, and heart damage.

Also, if you don’t get enough fiber, because you’re not eating whole fruits and vegetables, you can get constipated.

You also can lose muscle if you don’t get enough protein in your diet.
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.

How Can You Safely Get on a Liquid Diet ?

Pregnant or nursing women, and people who take insulin for diabetes, or anyone with a chronic illness shouldn’t go on a liquid diet.

If your doctor gives you the OK to go on a liquid diet, you should also see a registered dietitian, who can go over the diet with you and make sure you’re getting enough calories and nutrition. Your dietitian might recommend that you take a vitamin or nutritional supplement while you’re on the liquid diet.

Before you choose a liquid diet plan, know what you’re drinking. If you’re considering one of the commercial diets, look at the daily values on the nutrition facts label. Be sure you’re getting 100% of all the recommended vitamins and minerals.

You may also want to pick a diet that is not too low in calories and contains plenty of protein and fiber to keep you feeling full while you lose the weight gradually. Liquid diets that include a solid meal or two per day, or that teach you healthier eating habits, will be more likely to help you keep the weight off in the long run.

Liquid Supplemental Nutrition Drinks for People who struggle with a Loss of Appetite, or are Recovering from Surgery or an Illness

Nutrition in a bottle

Supplemental nutrition drinks can be helpful for people who struggle with a loss of appetite, have difficulty chewing, have trouble preparing balanced meals, or are recovering from surgery or an illness. You may be getting more sugar than any of the other ingredients. But if you can’t eat and that’s the only food that’s palatable, it’s better to get the calories. Experts warn that people who can still eat may be risking too many extra calories by consuming the drinks. They can lead to weight gain and a list of complications associated with obesity, such as high blood pressure and diabetes. It’s not okay to eat a full meal and then drink a liquid supplement, unless your goal is to gain weight or stop weight loss, because it has too many calories ².

Supplemental nutrition drinks provide a healthy balance of protein, carbohydrate, and fat. There are hundreds of varieties that fall into two general categories.

• Shakes, such as Boost or Ensure, are intended for oral consumption. You can find them on a grocery store shelf. These are formulated to help you meet general nutrition goals such as increased calories and protein. Some drinks are designed to be compatible with health conditions such as diabetes (Glucerna). Shakes are usually fortified with vitamins and blended with sugar to improve taste.

• Formulas are designed for more specific disease states such as cancer, chronic obstructive pulmonary disease, and later-stage kidney disease. These drinks (Jevity, Osmolite) can be consumed orally but aren’t designed to taste good, and are often used in feeding tubes. Your doctor will have to supervise use of these.

You don’t need a doctor’s okay to try a shake, but it’s a good idea to ask your doctor if any of the ingredients will interfere with your medications. For example, some drinks contain vitamin K, and sudden changes in vitamin K intake may interfere with the effect of the blood thinner warfarin (Coumadin).

These examples offer the ratio of calories, protein, carbohydrate, and fat per serving recommended by dietitian Stacey Nelson of Harvard-affiliated Massachusetts General Hospital.

(Source ²).

The risks

Supplemental nutrition shakes contain more than just healthy ingredients. You may be getting more sugar than any of the other ingredients. But if you can’t eat and that’s the only food that’s palatable, it’s better to get the calories. In that case, substituting one meal a day with a drink won’t hurt. Experts warn that people who can still eat may be risking too many extra calories by consuming the drinks. That can lead to weight gain and a list of complications associated with obesity, such as high blood pressure and diabetes.

Equally concerning is that nutrition in a can isn’t the same as nutrition from food. Even if they’re fortified, they still won’t contain all of the nutrients a whole food source would, check the nutritional label to find out about the types of vitamins and dietary supplements in the drinks.

Alternative option

A potentially healthier option is a shake or fruit smoothie that is food-based and found in the refrigerated section of the grocery store. These tend to have minimum added sugars and are less processed, and they should not contain excessive amounts of vitamins and minerals, herbs, or other unnecessary supplemental ingredients. However, these tend to cost more than the shelf-stable shakes.

What to look for

No matter which drink you choose, look at the ingredients. Ideally the first few ingredients should be fruit or forms of protein (such as milk). If sugar is the first or second ingredient, choose another healthier option. Equally important are the calories. If you’re replacing a meal, look for about 400 calories per serving. Experts advise against using the drinks as snacks, but if you must, then don’t go above 200 calories.

As for nutritional ratios in an 8-ounce serving, look for 10 to 20 grams of protein, no more than 6 grams of fat, and no more than 40 grams of carbohydrate, including sugar.

1. Mayo Foundation for Medical Education and Research, MayoClinic. Clear liquid diet. http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/clear-liquid-diet/art-20048505?pg=1[↩]
2. Harvard University, Harvard Health Letter. Supplemental nutrition drinks: help or hype ? http://www.health.harvard.edu/staying-healthy/supplemental-nutrition-drinks-help-or-hype[↩][↩]