What Is a Full Liquid Diet?

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As the name implies, the full liquid diet is one where only liquids—or foods that turn into a liquid at room or body temperature—are allowed. It may be recommended for a variety of reasons, such as when swallowing is a challenge or your digestive system is in distress. A liquid-only diet is meant to be a temporary measure while you are under a doctor's care.

Benefits

In some situations, a full-liquid diet is necessary to ensure safety. For example, if you’re having trouble chewing and/or swallowing, you are at risk for choking or aspirating when you eat or drink. A full liquid diet helps reduce that risk.

Eliminating chunks of food—and, therefore, food particles—can also help reduce complications if you have undergone dental work or had an injury involving your jaw. You may have open wounds in your mouth from incisions or missing teeth; sticking to a liquid diet until the pockets have closed will allow your mouth to heal and prevent food bits from getting stuck in openings and causing infection.

If your digestive system is slow or damaged from illness, disease, or surgery, being on a liquid diet while you heal can help manage pain and prevent complications, like a blockage in your intestines (bowel obstruction).

When preparing to have a test or imaging procedure to see inside your stomach and intestines you may need to be on a liquid diet for a day or two before. This will help make sure no undigested food is left in your gastrointestinal tract, which could affect the results.  

You may also need to be on a liquid diet to prepare for other medical procedures. Having only clear liquids before surgery, for example, is usually required to reduce the risk of aspiration. 

full-liquid-diet
Illustration by Joshua Seong. © Verywell, 2018.

How It Works

The full liquid diet allows you to have clear fluids as well as thicker ones, such as milk, fruit juice, shakes, and smoothies. 

Your doctor may give you permission to have other foods, such as strained purées or yogurt. If you have a medical condition that's influenced by what you eat and drink, you may have additional dietary restrictions.

These options will be your only ones while on a full liquid diet. This can make it difficult to get enough nutrients and calories each day. In addition to sticking with diet-compliant foods and beverages, you will need to follow your doctor's instructions closely to ensure adequate nutrition. A registered dietitian or nutritionist can also be a helpful resource.

Duration

The full liquid diet is generally only prescribed for a few days to help you transition back to your normal diet. It’s rarely required for longer than two weeks. Exceptions may be people who are preparing for bariatric surgery, recovering from a fractured jaw, or who use the diet to manage acute flares of certain medical conditions.

Due to its restrictive nature, you should be closely monitored by your doctor when on a full liquid diet for more than a few days.

What to Eat

You’ll have your choice of beverages on a full liquid diet. With the right tools, you can also make many solid foods diet-friendly. Melting, thinning, straining, or puréeing fruits, vegetables, cheese, and even meat can help you stay nourished and satisfied.  

Compliant Foods

  • Fruit and vegetable juice (no pulp)

  • Broth

  • Soft drinks

  • Sports drinks, electrolyte-replacement drinks

  • Coffee, tea

  • Milk or dairy-free milk alternatives (soy, almond)

  • Milkshakes, malts, smoothies

  • Clear or creamed soups (thinned, strained, no solids)

  • Honey, syrup, sugar

  • Gelatin, pudding, custard

  • Ice pops, ice cream, frozen yogurt, sorbet (no nuts, candy, solid toppings/coatings)

  • Yogurt (regular or Greek; no granola, seeds, fruit chunks)

  • Melted cheese

  • Powdered protein, dry milk, other nutritional supplements

  • Liquid dietary supplements (Ensure, Glucerna, Boost)

Non-Compliant Foods

  • Meat (unless puréed, thinned, and strained)

  • Tofu, meat substitutes

  • Nuts and seeds

  • Raw fruits and vegetables

  • Solid cheese

  • Soft or mashed food (e.g., potatoes)

  • Soups or stews with noodles, meat, or vegetables

  • Bread

  • Whole pasta or rice

  • Cereals, granola, oats

  • Applesauce

  • Potato chips, crackers, pretzels, popcorn

  • Muffins, cakes, cookies, pastries

  • Hard or chewy candy 

  • All other solid foods unless specifically approved by your doctor

Fruits and vegetables: Fruit and vegetable juice is allowed on a full liquid diet as long as it has been strained to remove any solids (like pulp). You may need to avoid any high-fiber juice such as prune juice all together.

Mashed potatoes and other types of vegetable mash are generally not approved but can be if they are sufficiently thinned. You can blend them with butter, gravy, or sauces, season to taste, and thin with water or broth. They should be no thicker than a smoothie when you're done.

Grains: Cooked cereals can be thinned with water or milk, then strained. Farina and rice cereal are also easy to make less viscous. If you’re trying to add nutrition, prepare your cereal with whole milk or creamer instead of water or skim milk. 

Dairy: Milk or lactose-free alternatives are approved. Drink your favorite by the glass and/or add it to smoothies and shakes for extra nutrition.

Powdered milk is a versatile option that can be added to cereals, soups, and eggs. You can boost the protein of regular milk by mixing it with dry skim milk before using it to create liquid meals. 

Regular yogurt works well as a base for sweeter-tasting liquid meals, and Greek yogurt can be a good base for more savory recipes. 

Cottage cheese is easy to blend into a liquid meal and most shredded cheese will melt easily with a little heat. While you’re limited to a full liquid diet, use butter or margarine as often as you can to add calories and fat to your meals. 

Protein: Meat is approved as long as it’s the consistency of baby food. Mix meat with potato flakes and milk before or after cooking to give it the right consistency for a liquid diet.

Nut butter is a good source of healthy fats and protein that can be easily added to shakes or smoothies. Eggs, egg whites, or egg substitutes can be prepared soft and blended into a liquid meal. 

Dessert: Ice cream, frozen yogurt, and ice pops that melt at room temperature are approved on a liquid diet as long as they do not contain nuts, candy, or other hard pieces. Gelatin cups are allowed as-is. Puddings and custards can be thinned to a liquid consistency.

If you need to add calories, try topping ice cream, pudding, malts, or milkshakes with fruit thoroughly blended with whipped cream. 

Beverages: Any clear broths, juices, or other drinks are approved on a full liquid diet. However, fruit and vegetable juice may have more fiber than your doctor has recommended for you.

Making your own juice with a high-speed blender or juicer allows you to control the consistency. You can also pour the juice through a mesh sieve or tea strainer to catch any lingering residue.

You can use milk, half-and-half, and non-dairy creamer to add calories to coffee or tea. Other hot beverages like cider, chai, and milk-based espresso drinks are also approved as long as they do not contain solid pieces such as chocolate flakes or mulling spices.

To ensure you’re properly nourished and hydrated, aim to drink at least 64 fluid ounces by the end of each day.

Recommended Timing

One challenge of a liquid diet is knowing whether you’ve consumed adequate nutrition in a given day. As a general rule, have enough to feel satisfied.

That said, if you have certain digestive disorders or are recovering from illness or surgery, it's not uncommon to feel full quickly. The discomfort may set in before you've taken in enough calories to be adequately nourished. 

Start by drinking as much as you comfortably can every 15 minutes. Try taking sips from a small glass rather than trying to drink larger amounts in one sitting. You may need to plan your liquid meals as frequently as six to eight times a day.

Cooking Tips

The easiest way to thin soft food to make it suitable for a full liquid diet is to add water. If food doesn't become a liquid at room or body temperature, as ice pops would, apply a little extra heat.

Dairy products like shredded cheese can be melted in the microwave and added to soups or purées. Chocolate can be melted in a saucepan on the stovetop. 

Kitchen tools like food processors can be a big help if you’ll be making liquid meals for yourself at home. A blender is particularly useful as you purée fruits and veggies, as well as use it on a lower setting to easily “pulse” thicker foods like oatmeal into a safe consistency. 

Pasta, rice, and potatoes can be cooked until they are very soft, then thinned with water, butter, or gravy. You can also use water or milk and heat to soften crackers, which can then be added to soup or broth. 

Modifications 

Depending on why you have been prescribed the diet, you may be given additional restrictions. If the diet is to clear your bowel before a colonoscopy, you may be told to avoid any gelatin or beverages with red or purple coloring. Dyes can stain the tissue of the intestines, which could be mistaken for blood on a scope.

If you're tempted to incorporate other options on a full liquid diet because you're feeling too limited, talk to your doctor before doing so. While a full liquid diet may have been prescribed to you, there may be cases when its guidelines can be loosened.

Babies and Children

Adjustments may be needed to make a full liquid diet safe for babies, toddlers, and children. For example, honey should not be given to a child under a year old.

While a young child may already be eating a diet with few, if any, solid foods, there are also other specific considerations for this age group. When creating purées or liquid meals, avoid adding any new foods to your child’s diet. Stick to only those you have already introduced.

To ensure your child has a balance of nutritious liquids, you may want to limit how much milk they drink, as it can be very filling. Adding electrolyte drinks or ice pops can also help prevent dehydration. 

Considerations

Following a full liquid diet is quite a change—one that will require adjustment, planning (both in terms of logistics and for your overall health), and integration into your everyday work, home, and family life.

General Nutrition and Safety

Full liquid diets tend to be low in calories. The typical goal is around 1,500 calories per day, but can be as low as 800 calories. And while they can be nutritionally balanced, careful planning is required. You may feel not feel hungry on a full liquid diet, but the diet usually doesn’t contain adequate fiber or essential vitamins and minerals.

Your entire medical team will monitor you for weight loss and nutrient deficiencies that can occur when you are on a restricted diet such as this. Your doctors, a dietitian, and/or nutritionist can help you design meals with enough calories and nutrition to sustain you, as well as recommend any supplementation you may need.

Sustainability and Practicality

If you’re on a liquid diet while you’re recovering from an illness, injury, or a surgical procedure, you might not feel up to the work required to prepare meals. If friends and family can help, make sure they know what the requirements of your diet are. 

You can also prepare many liquid meals in advance and freeze them. Purchasing a larger capacity food processor or blender can help you make bigger batches. Stock up on as many items as you can beforehand, especially beverages and supplements.

Flexibility

While you won’t have the dietary variety you’re accustomed to on a solid food diet, you won’t be completely restricted on a full liquid diet.

Dining out while following this eating plan usually isn't much of a challenge, though you may need to order à la carte items rather than entrees, or modify your choices (for example, order soup, just don't eat the chunky ingredients).

Dietary Restrictions

Ask your doctor about how other dietary restrictions or health conditions you have will be affected by being on a liquid-only diet, as well as how a full liquid diet may need to be adjusted in response to these needs.

For example:

  • After gastric surgery, your doctor might tell you to avoid acidic drinks like orange juice or coffee, which can irritate the lining of your stomach as it heals.
  • Having kidney or cardiovascular disease may require that you restrict your fluid intake. If you need to go on a liquid diet, your doctor will provide special instructions.
  • Maintaining blood sugar levels is a concern if you have diabetes and need to follow a full liquid diet. Ask your doctor how many grams of carbohydrate each liquid meal will need to contain. Supplements like Glucerna may be helpful.
  • If you follow a diet to manage gastroparesis, you may need to avoid any high-fat liquids or additions, such as butter. If you are managing hypertension with a sodium-restricted diet, you would want to continue to avoid adding salt to your food—even in liquid form.
  • If you are lactose intolerant, you'll want to avoid using cow's milk to thin foods or add calories to your coffee and tea. You'll also need to closely inspect the list of ingredients and labels on liquid nutritional supplements, as many are milk-based.

Cost

You may be able to save yourself some work by purchasing foods that have already been puréed, though fresh options can be pricey (and, in some cases, hard to find). You may find it's more cost-effective to purée food yourself at home. 

Baby food is an option but doesn’t come in portions adequate enough for an adult's meal. You can use strained meat, veggies, and fruit intended for babies as the base for a liquid meal. However, though typically only a dollar or so per jar, this can quickly add up.

The kitchen tools that make food prep for a liquid diet easier can be expensive. If you only need something that can handle the basics, you can usually find more affordable options—especially if you shop online.

Side Effects

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. Your doctor may recommend you add an over-the-counter powdered fiber supplement, such as Metamucil, to your liquid meals. 

It’s also not uncommon to have frequent, loose stools on a full liquid diet, as you are not consuming any solid food. As you begin to return to a solid food diet, your bowel movements should adjust accordingly. 

Weight loss can be sudden and significant—even if you're not on a full liquid diet for a long time. Once the caloric deficit created by the low-calorie diet is corrected, weight is typically restored. 

The low caloric value and lack of essential vitamins and minerals may cause you to feel fatigued, irritable, depressed, or generally unwell.

Full Liquid Diet vs. Other Diets

A full liquid diet is similar to other diets used to treat digestive disorders or help you get ready for (or recover from) surgery. However, there are some key differences.

Clear Liquid Diet

A full liquid diet is similar to a clear liquid diet, which is often necessary before surgery and is a required part of the prep for a colonoscopy. The main difference is that a clear liquid (surgical liquid) diet only allows fluids that are completely free of particulates, such as water, clear juice like apple juice, and broth. Other juices and bullion may be acceptable as long as they have been thoroughly strained. Thick, opaque fluids are not allowed.

clear liquid diet options
Illustration by Cindy Chung, Verywell

A 2016 review of nine studies on colonoscopy preparation found that patients who followed a low-residue diet, as compared to a clear liquid diet, were better able to stick with their eating plan and more willing to repeat the diet in the future. In addition, they noted no differences in the quality of their preparation or adverse effects.

A 2017 study echoed that patients preparing for the procedure may not need to be on a clear liquid diet unless they have certain risk factors.

A full liquid diet falls somewhere in the middle of these two plans. But given this research, it may be worth talking with your doctor about a more liberal diet option if following a full liquid diet is too challenging.

Mechanical Soft and Soft (Puréed) Diets

The mechanical soft diet and soft diet are similar to the full liquid diet but have one key difference. On a mechanical soft diet, foods are excluded based on their texture or consistency, not their type. On a soft diet, you may need to avoid foods that are high in fiber or fat, even if they are easy to chew.

A mechanical soft diet is typically recommended if you're healing from an injury or surgery involving your mouth, jaw, or throat. A soft diet rests your digestive system after illness or surgery. A full liquid diet, on the other hand, might be recommended in both cases.

The mechanical or soft diet may be recommended for you as you progress from a liquid diet back to a regular solid food diet.

Dysphagia Diet

If you've been on a full liquid diet or you have a condition called dysphagia, your doctor may recommend a special, three-stage diet to help you progress back to eating solid food.

During the first stage, you can only have food that doesn’t need any chewing, such as yogurt. In the next stage, you can add foods that only need a little bit of chewing, like soft-boiled eggs. In stage three, you can add fruits and veggies that have been chopped into tiny pieces or mashed up.

After you've moved through each of the three stages, you'll be ready to resume a solid food diet. 

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  1. Barajas-Gamboa J, Corcelles R, Kroh M. Endoscopic Intramural Surgery Part II: Muscular Division. Dig Dis Interv. 2018;02(04):368-374. doi:10.1055/s-0038-1676504

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