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The Liquid Elemental Diet: Rest, Reset, and Restore

A Guide for Removing & Reintroducing Solid Food to Heal Your Gut with an Elemental Diet

It’s not uncommon for us to have patients in the clinic who’ve struggled with lifelong gut issues. They’ve tried various diets, supplements, and tests but just can’t seem to find any significant or long-term relief. If this sounds familiar, I want to reassure you that you don’t have to stay on this roller coaster ride of ups and downs. In my clinical experience, implementing the right therapeutic supports in the right order can lead to dramatic improvements pretty quickly. 

While we have a spectrum of treatment options when it comes to healing your gut (like probiotics and a low FODMAP diet), one of the most science-based and impactful is a liquid elemental diet. While I don’t recommend starting with this, for my patients who haven’t responded to other therapies, the liquid elemental diet can be the treatment that makes all the difference. 

A liquid elemental diet is a predigested meal replacement shake that provides all the nutrients you need in an easily absorbable form. By design, it helps your digestive system rest, alleviates negative symptoms, and promotes GI tract healing. In other words, a liquid elemental diet allows you to hit the reset button on your gut. But what do you do after you’ve completed the elemental diet?

In this article, I’ll delve into the science behind a liquid elemental diet, share the specifics on how to incorporate it into your routine, and the process for reintroducing solid food afterward. Let me jump right in with some background. 

What is a Liquid Elemental Diet?

An elemental diet is a liquid meal replacement shake that’s predigested, hypoallergenic, antibacterial, and anti-inflammatory. Because the formula is low in fiber and contains nutrients that are easily absorbed, it allows your gastrointestinal system a chance to rest and repair.

The concept of a liquid elemental diet may be new to you, but the ancient Greeks and Egyptians used this therapy (via enema) as far back as 3500 years ago [1, 2]. Around 1910, significant advances in tube feedings (enteral feedings) and elemental formulas started to emerge [1]. And then, in the 1960s and early 1970s researchers began to document the effects of elemental diets on human health [3].  

Until fairly recently, a liquid elemental diet wasn’t an option that was all that accessible or attractive. You had to have a prescription from your doctor and the taste was questionable. Fortunately, you no longer need a prescription, and we have tastier formulas now, which makes this therapy a viable option for many more people. 

Full v/s Semi-Elemental Diet Formulas

There are two types of liquid elemental diet formulas—full elemental and semi-elemental. Both come in a powder form that you mix with water. Here’s a table giving you a side-by-side comparison of important features (4):

Full ElementalSemi-Elemental
Low in fiber and prebiotics
Easily digested
Proteins are completely broken down 
More cost efficient
Better taste profile

As you can see, the main difference between the formulas is the size of the proteins. In the full elemental formulas, the proteins are completely broken down into amino acids, and in the semi-elemental formulas, the proteins are partially broken down (in the form of whey protein) [4]. The great news here is that these differences don’t seem to have much of an impact clinically [5, 6]. So, you can first try the semi-elemental formula (with hydrolyzed whey protein), which tastes better and costs less, knowing that a wide range of patients have an easier time tolerating, digesting, and assimilating it over a full elemental formula [4]. If you find you don’t tolerate semi-elemental for some reason, you can always go with the full elemental option

We’ve got the background out of the way, so let’s dig into why we think a liquid elemental diet works so well.

Key Takeaway: A liquid elemental diet is a predigested, hypoallergenic, anti-inflammatory, antibacterial meal replacement shake that can reset your gut. In a full elemental formula, the proteins are completely broken down into amino acids, and in a semi-elemental formula, the proteins are partially broken down, but both appear to be similarly effective.

How Does a Liquid Elemental Diet Work?

A liquid-only diet can be incredibly reparative for your digestive tract. Let me illustrate this with an analogy—if a runner sprains an ankle but continues to run, it’s unlikely the ankle will completely heal. This same concept applies to your gut. If you have a gut “injury” and are eating three times a day every day, it can be hard for your gut to repair itself. Using a liquid elemental diet can give your gut a break and aid in healing in the same way that avoiding activity can help heal a sprained ankle.

When we look at the research, the mechanisms by which an elemental diet helps your gut differ to some degree for every condition and person. But in general, a liquid elemental diet can:

  1. Give your digestive system a break and a chance to rest, heal, and then repair [7, 8]
  2. Reduce inflammation [7, 9]
  3. Starve microbial overgrowths [10]

I suspect an elemental diet works so well, in general, because it has such a favorable impact on the small intestine. Your small intestine is home to the majority of your immune system and is the most prone to damage (leaky gut). Digesting and absorbing nutrients from food places a huge burden on your small intestine. Since the elemental diet is absorbed rapidly, it may allow the majority of your small intestine to have a break from absorbing nutrients, fostering healing and repair. 

At this point, you’re likely wondering how to know if you need a liquid elemental diet. Let’s review what the research says about using this therapy for various conditions.

Key Takeaway: A liquid elemental diet gives your digestive system a break from the hard task of digesting solid foods, especially those that are particularly irritating or inflammatory. It can also help reduce inflammation and starve microbial overgrowths.

Who Should Use a Liquid Elemental Diet?

Unfortunately, we don’t have a ton of quality research on liquid elemental diets. We probably have the most research on using elemental diets for eosinophilic esophagitis (EoE) and Crohn’s disease (a type of inflammatory bowel disease—IBD) [5, 11], but there’s also some support for using this therapy with other conditions like:

  • Eosinophilic gastroenteritis [12]
  • Small intestinal bacterial overgrowth (SIBO) [10]
  • Irritable bowel syndrome (IBS) [10]
  • Celiac disease (that doesn’t improve with a gluten-free diet) [13, 14]

Here’s a table summarizing the research we have on liquid elemental diets:

Condition StudiedType of Study Results

Eosinophilic esophagitis (adults and children)

Meta-analysis of observational studies [11]
Elemental diets induced remission in 90.8% of EoE patients

Crohn’s disease (adults and children)

Meta-analysis of randomized controlled trials [5]
Elemental diets (full or semi-elemental) may be sufficient to induce remission in patients with Crohn’s who cannot or will not tolerate steroids

Crohn’s disease

Prospective observational study [6]
A semi-elemental diet led to fewer stools per day, less malnourishment, less disease activity, and more remission. Following a semi-elemental diet exclusively for 12 weeks did not result in malnutrition 

Rheumatoid arthritis

Systematic review [15]
An elemental diet may relieve subjective symptoms like morning stiffness and pain, but only temporarily. The diet had no effect on inflammatory biomarkers or other objective measures. It’s not clear whether benefits were related to the elemental diet or weight loss
Eosinophilic gastroenteritis (EGE) and associated colitis
Systematic review of observational studies [12]
Elemental diets may improve clinical outcomes in children with EGE


Clinical study [10]
A two-week full elemental diet normalized lactulose breath tests (indicating SIBO was cleared) in SIBO patients more often than antibiotics

I want to make the point here that not having much research yet doesn’t mean a liquid elemental diet isn’t an effective or valid option. This is an example of what I like to call being “evidence-based but not evidence-limited.”  In the clinic, I’ve found a liquid elemental diet to be very helpful for people with many GI conditions like gastroesophageal reflux disease (GERD), bloating, IBS, diarrhea, constipation, and SIBO. And our clinic is hoping to publish research on our findings in the near future, so stay tuned.

Liquid elemental diets, whether semi or full, can work very well to improve gut health for people who haven’t responded to other interventions. But how safe are they, and is there anyone who shouldn’t use them?

Key Takeaway: So far, there’s evidence to support the use of liquid elemental diets for SIBO, Colitis, Crohn’s, EoE, and IBS. But our clinical experience has shown positive effects for other GI upsets too, so it may be worth a try if you have stubborn GI symptoms that haven’t responded to other treatments. 

Are Liquid Elemental Diets Safe?

When thinking about liquid diets, I can see how it would be easy to assume they might be lacking in at least some of the macronutrients and micronutrients you need. But it’s important to remember that elemental diets, whether semi or full, are designed to provide for your nutritional needs. A man-made medical food probably doesn’t have the same depth of nutrients that a whole-food diet does, but it’s an appropriate substitute while you’re working to heal your gut to the point that you can digest and absorb the nutrients you need from solid food. 

Additionally, the research we have so far suggests elemental diets are safe (even long-term) for patients with a variety of GI conditions [5, 8, 16, 17, 18]. It’s probably reasonable to assume that elemental diets are generally safe for most people. But it’s always best to be cautious—if you plan to use a liquid elemental diet for longer than a few days, you should have your physician monitor you for any negative side effects [8]. 

I use liquid elemental diets with patients who have all manner of health conditions, but there are a few caveats. Elemental formulas contain easily absorbed carbohydrates (maltodextrin), which could potentially feed the fungus or microbes in people who have upper GI fungal overgrowth, thrush, or excessive phlegm. There doesn’t seem to be any research to suggest that elemental diets are contraindicated for these conditions, but it’s something to be mindful of. Likewise, if you have a history of disordered eating or plan to use this therapy to lose weight, a liquid elemental diet may not be the best option.

If you’re considering a liquid elemental diet but feel intimidated by the thought of a liquid-only diet, let me allay your fears—it doesn’t have to be all-or-nothing. We have many options when it comes to implementing an elemental diet, so let me share how we go about this in the clinic.

Following a Liquid Elemental Diet

One feature that makes a liquid elemental diet so appealing is its versatility. Rather than thinking you must solely rely on the formula for days on end, it’s best to think about your personal needs. Generally, liquid elemental diets are used in one of three ways in terms of duration:

  1. Short term, as a reset—using the full or semi-elemental formula exclusively (your only source of calories) for 1–4 days. I’ve found this to be very effective for quelling gut flares.
  2. 1–3 weeks, as exclusive liquid nutrition—using the full or semi-elemental formula exclusively as a formal treatment for microbial overgrowths or other stubborn gut issues. (This should be done under medical supervision).
  3. Longer-term, with intermittent or hybrid use—combining the full or semi-elemental formula and normal food.

We don’t have much research comparing the effects of short-term versus long-term use of an elemental diet. One way you may approach this process is to start with a 1–4 day reset trial. Depending on how well you do with that, you may want to extend it for 1–3 weeks. If you have pretty severe GI symptoms, a longer duration may be just what you need to achieve your desired result. But I want to caution you to always have the supervision of a qualified healthcare provider when using an elemental diet for exclusive nutrition longer than four days

When using the liquid, you can consume as much of the formula as you need. Here’s a dosing calculator to help you determine what’s best for you. It’s best to sip on the solution throughout the day rather than consuming large amounts in a short period of time. Sipping on the formula can help keep a steady supply of nutrients and calories in your system—this will keep you from getting hungry, keep your blood sugar from dipping too low, and help fight fatigue. 

When you feel like you’ve achieved the maximum benefit, it’s a good time to transition back to solid food. In the clinic, some patients are hesitant to add solid foods back into their diet because they feel so great they don’t want to rock the boat. Others jump right in with any type of solid food. The overall goal is to heal your gut to the point that you don’t need to use an elemental diet. But it’s equally important to consider how you add foods back in after you’ve finished the elemental diet process. Let me share how we educate our patients on transitioning back to solid food in the clinic. 

Key Takeaway: The research we have suggests elemental diets are safe (even long-term) for patients with a variety of GI conditions. However, you should seek supervision if you want to do an elemental diet any longer than 4 days.

Reintroducing Solid Food After an Elemental Diet

A liquid elemental diet is a tool we use to repair your GI tract, which allows for better food tolerance so you can consume the widest variety of food possible. The reintroduction of foods is an extremely important but often forgotten step. 

There’s no specific timeframe for reintroducing foods—I encourage you to listen to your body. When you’ve reached your desired level of symptom improvement, it’s probably the right time. 

In the clinic, we use a hybrid approach where you continue to use the elemental formula to replace solid foods while you’re slowly adding in whole foods. I’ve found this to be the best practice, especially if you haven’t had solid food for more than 4 days. Going through this process can help ease the burden on your immune system (which mostly lives in your small intestine) and allow you to better identify foods that you may be sensitive or allergic to. 

But which foods do you add back first? There’s no exact answer here, but we can look to the research to guide us. It’s likely best to start with the least allergenic foods and then gradually increase your variety slowly over time. While you can be allergic, sensitive, or intolerant to any food, there are certain foods that seem to be particularly high risk for producing symptoms. In the clinic, we’ve seen the most success with food reintroduction when our patients start with the least allergenic options and then move down the list in a stepwise manner.  

Here’s a list of the allergenicity of foods based on EoE research [19]:

  • Least allergenic—non-legume vegetables, non-citrus, and non-tropical fruits
  • Minimally allergenic—citrus and tropical fruits, melons, berries, rice, millet, and quinoa
  • Moderately allergenic—legumes, oats, barley, rye, other grains, lamb, chicken, pork, and turkey
  • Most allergenic—fish, shellfish, corn, peas, beef, soy, egg, wheat, nuts, peanuts, and milk

So, what does the hybrid approach look like in practice? Here’s a sample 3-day meal plan and how you might advance through the reintroduction process week-by-week, taking food allergenicity into account:

The Liquid Elemental Diet: Rest, Reset, and Restore - 3%20day%20meal%20plan L

As you can see, week one has less variety, but as you move through the process, you’ll be adding in even more foods while still utilizing the elemental diet shake. The overall goal here is to decrease your use of the shakes and increase the amount and variety of solid food you’re eating each day. While you’re going through this process, take note of your symptoms—if you notice a certain food doesn’t sit well with you, then leave that food out for a while longer and come back to it later. And remember, there’s no need to be perfect—I’m a huge fan of listening to your body and honoring what it tells you.

Another important point I should make here is about food quality. Following a liquid elemental diet protocol and reintroducing solid foods is a huge accomplishment. Maintaining your excellent results will likely require you to consider your daily dietary pattern—if you go back to consuming the standard American diet (or another pro-inflammatory diet), you could end up with the same symptoms you started with. I’m by no means saying you can never have a piece of cake or drink some alcohol, and I never want to create food fear. But your overall dietary pattern does impact the health and balance of your gut, so focus on wholesome foods and pepper in special treats based on how you feel.

Here’s another graphic detailing how you could go about reintroducing solid foods along with specified timeframes:

The Liquid Elemental Diet: Rest, Reset, and Restore - Elemental%20Diet%20Food%20Reintroduction%20Protocol L

The hybrid approach is a great way to transition off of a liquid elemental diet because it gives you the most chance of success. But it’s also an effective option for people who have nagging symptoms off and on. Here are some of the research findings on using the hybrid approach for people with Crohn’s disease and EoE:

  • A meta-analysis of people with Crohn’s disease found a hybrid approach (elemental diet combined with a normal diet) appeared to be better than no special diet for helping patients maintain remission [16].
  • A randomized controlled trial (RCT)  of patients with Crohn’s disease found those who received up to 50% of their daily calories from elemental shakes had reductions in gut symptoms and flares [8]. 
  • An RCT in patients with EoE found that 6 weeks of a combined elimination diet and elemental diet led to a better remission rate and improved quality of life compared to an elimination diet alone [20]. 

Additionally, a study involving 36 patients with AIDS who were non-responsive to antiviral therapy found that adding an elemental diet drink in addition to a normal diet led to improved immune function and reduced intestinal permeability after 3 months [21]. This research supports our clinical observation that using elemental diets exclusively isn’t always necessary. A hybrid approach, which is much easier to implement, can still provide clinically meaningful benefits.  

Key Takeaway: It’s best to use a structured, hybrid approach when reintroducing solid foods after a liquid elemental diet. Start with low-allergenic foods and add them back slowly over the course of several days to better determine any foods that may trigger your symptoms. Continue to replace one or two meals each day with the liquid formula while you transition back to solid foods. 

Reset Your Gut with a Liquid Elemental Diet 

A liquid elemental diet is a predigested meal replacement shake that can be incredibly reparative, antibacterial, and anti-inflammatory for your gut. It isn’t the first place to start if you’ve got gut symptoms, but it’s a simple, safe, dietary-based option if you’ve tried other gut-directed therapies without complete symptom resolution. 

It may seem daunting to try a liquid elemental diet, but we have a lot of freedom with how we apply this type of therapy—whether you choose a short reset, use it for sole source nutrition for a few weeks, or opt for the hybrid approach, you’ll likely experience meaningful benefits. It’s best to have the guidance of a trusted healthcare provider during this process, and reintroducing solid food is of utmost importance. You may want to follow the structured reintroduction process above for the best chance of success. 

If you’re struggling with negative symptoms, check out my book Healthy Gut, Healthy You, where I offer a step-by-step gut-healing protocol. If you’re someone who needs or desires more assistance, we’d love to see you in the clinic.

The Ruscio Institute has developed a range of high-quality formulations to help our patients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you.

➕ References
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