What Is a Full Liquid Diet and When Is It Used?

Mugs and cup of tea and coffee next to glasses of water, milk and fruit juice
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A full liquid diet is made up of liquids only, but unlike a clear liquid diet that essentially only allows clear beverages and broth, a full liquid diet includes thicker juices, milk, and pureed soups.

It’s often used before or after some types of surgery or if you have certain digestive conditions that won't allow you to eat solid foods. In most cases, you'll only be on a full liquid diet for a limited amount of time, and the diet is often a stepping stone to the mechanical soft diet.

Full Liquid Diet vs. Clear Liquid Diet and Mechanical Soft Diet 

A full liquid diet is often used as a bridge between a clear liquid diet and a regular or mechanical soft diet. It has a greater range of items than a clear liquid diet, yet is still fairly restricted compared to a mechanical soft diet, which allows most types of foods as long as they’ve been pureed, slurried, or pulverized.

Juices and broths allowed on the clear liquid diet need to be clear, so the choices are more limited. Clear juices like apple juice are fine on both diets, but on the full liquid diet you can also consume vegetable juices and citrus juice if fine, as long as the pulp is strained out.

In addition to clear broth, creamed soups are allowed as long as they don’t contain any lumps or pieces of meat, vegetables, or noodles. Cooked cereals are also fine as long as they've been strained. Tea and coffee are allowed on both diets, but on a full liquid diet, you can also add milk or cream if you like.

You can also drink milk or milk substitutes such as almond, soy, or rice milk, if you’re lactose intolerant.

Nutrition Goals of a Full Liquid Diet

Full liquid diets are usually low in calories and nutrients. The goal is usually about 1500 calories and 45 grams of protein. You may feel like you're getting enough to eat, but this diet doesn’t contain enough fiber, vitamins, and minerals to be used long-term.

If, for some reason, you are on this diet for a longer period of time your doctor may suggest adding liquid dietary supplements like Ensure to your daily meal plan. If you still need more calories, powdered milk can be added to creamed soups and you can sweeten foods with sugar or liquid sweeteners such as honey or corn syrup. Adding butter or margarine to your hot cereals is also an option. If you need to cut back on calories, artificial sweeteners are also allowed on a full liquid diet.

Foods Allowed on the Full Liquid Diet

  • All kinds of fruit and vegetable juice (no pulp)
  • Pureed fruit or vegetables
  • Milk
  • Soy or almond milk
  • Yogurt (without fruit chunks)
  • Melted cheese
  • Eggs can be eaten like a soft custard
  • Honey
  • Syrup
  • Coffee
  • Tea
  • Soft drinks
  • Sports drinks
  • Water
  • Strained cooked cereal
  • Broth
  • Creamed soup (no pieces or chunks of vegetables or meats)
  • Pureed meat can be added to soup (again, no chunks)
  • Sugar
  • Flavored gelatin
  • Ice cream (no fruit, chocolate chips, etc.)
  • Sorbet and frozen yogurt

Example Meal Plan for One Day

Here's an example of a daily meal plan filled with foods you can eat on a full liquid diet. It has around 2,000 calories, but you can alter the amounts depending on your appetite and calorie needs.

Breakfast

  • One cup of fruit juice
  • One cup of strained cooked cereal
  • One glass of water or cup of coffee
  • Morning Snack
  • One cup of pureed fruit
  • One cup of tea

Lunch

  • One cup of pureed vegetables
  • One glass of milk or soy milk
  • One cup of chicken, beef or vegetable broth
  • Afternoon Snack
  • One cup of ice cream
  • One glass of water

Dinner

  • One cup of pureed fruit
  • One cup of creamed soup
  • One glass of fruit juice
  • One glass of water
  • One glass of cow's milk or soy milk

Nighttime Snack

  • One cup of yogurt
  • One cup of fruit juice
  • One glass of water

Note: if you can't tolerate milk, choose soy or almond milk, and be sure to read the labels of liquid nutritional supplements because some of them are milk-based.

Possible Side Effects of a Full Liquid Diet

If you need to be on a full liquid diet for more than a few days, you may become constipated from the lack of fiber and weight loss is possible with the low calorie count. Of course, that means that many dieters are tempted to go on a liquid-only weight loss diet, but it's not a good way to lose weight. Full liquid diets should only be done with medical guidance.

The liquid diet can be low in vitamin B12, minerals, and protein so long-term use (more than two weeks) would require dietary supplements to prevent nutrient deficiencies and muscle loss.

What About the Fiber From Fruit and Vegetable Juices?

There probably isn't too much, even if you use high-speed bullet blender, Vita-mix, or juicer to make your own juices at home.  However, if you need to be on a low-fiber diet while you're on the full liquid diet, it may be good to avoid high fiber juices. Ask your doctor.

It's also a good idea to ask your doctor about any additional dietary restrictions you may have. For example, a person on a Gastroparesis diet may need to avoid high-fat liquids and a person on a sodium-restricted diet may need to avoid salty fluids.

A Word From Verywell

Just like the clear liquid diet, mechanical soft diet, and a restricted fiber diet, the full liquid diet is only used as a short-term diet in a special situation, such as after surgery, and only with medical supervision, so if you're not enjoying it know that chances are, you won't be on it for long.

If you’re not sure if a food you want to eat is acceptable for a full liquid diet, ask your doctor or dietitian before you add it to your diet.

Sources:

Maher AK. "Simplified Diet Menu." Eleventh Edition, Hoboken NJ, USA: Wiley-Blackwell Publishing, October 2011.   

University of Wisconsin School of Medicine and Public Health. "Modified Diet: Full Liquid Diet." 

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