How To Reintroduce Foods Post-Elimination Diet (Without the Flare-Ups)

Here’s a situation I see all the time in my functional medicine telehealth practice. 

A patient has removed several foods from their diet because they were reacting to so many things. Now, they’ve taken some time to heal their gut and immune system, and it’s time to start reintroducing some of the things they’ve cut out—but instead of being excited to taste their old favorites, they’re nervous that all of their symptoms are going to come flooding back. 

This is so understandable. But the goal of an elimination diet is not long-term restriction, it’s to eventually be able to expand your list of safe foods more and more, while still feeling your best. (1) And in this article, I’m going to show you exactly how to do it. 

Elimination Diets: An Overview and the Three Phases

An elimination diet is a strategic, short-term eating plan that can help you improve your health in two key ways. 

First, it can help you identify hidden food intolerances or sensitivities that don’t always show up on tests or make themselves obvious in other ways. Second, it gives your gut and immune system a break from potentially triggering foods while you work on healing underlying causes of reactivity. 

Elimination diets can be modeled on different dietary templates depending on your individual symptoms and health profile. 

For example, someone who has been diagnosed with irritable bowel syndrome (IBS) may follow a low FODMAP diet as an elimination diet, because foods high in FODMAPs (a group of fermentable carbohydrates that can feed overgrown bacteria) have been shown to trigger IBS symptoms. (2) Someone with known or suspected histamine intolerance may follow a low histamine diet template. 

In other cases, a more generalized template is followed, where a wide range of potentially triggering foods including dairy products, gluten, eggs, nightshade vegetables, legumes, shellfish, and/or nuts and seeds may be eliminated. 

There are three phases of an elimination diet: 

Phase One: Elimination 

During the first phase, you eliminate all of the foods you and/or your practitioner have decided on. This phase is restrictive, but it’s not forever. During this time, you’ll track your symptoms and observe how you feel. And, importantly, you’ll work on identifying and addressing underlying causes of immune system and autoimmune reactivity, leaky gut, and other imbalances and issues that commonly underlie food sensitivities and other symptoms. (3) 

READ MORE: 12 Of The Most Common Food Intolerances | Dr. Will Cole 

Phase Two: Reintroduction

In the reintroduction phase, you’ll slowly add one healthy eliminated food at a time back into your diet, observing and tracking how you feel. If you notice any symptoms, remove the food again. If you don’t, you can likely continue eating it. I’ll cover this phase in much more detail below. 

Phase Three: Personalization 

This is where you take what you’ve learned and work it into a longer-term plan. Things may continue to change over time, and you don’t have to stick to your exact plan forever, but during this phase you should have a clear understanding of which foods you’ll generally be avoiding and which you’ll be enjoying moving forward. 

What To Do Before Reintroducing Foods 

Before you move into the reintroduction phase, it’s important to make sure that you have reached a plateau of symptomatic improvement, and that you’ve done the bulk of the work on healing the root causes of your reactivity. 

We don’t need to achieve perfection, but one of the biggest mistakes I see people making with elimination diets is reintroducing foods too quickly. I think this is largely because of a lot of advice out there that specifies an exact period of time for the elimination phase, and it’s usually 3-4 weeks. 

This might be enough time for some people, but for those with more complex health issues or who have been experiencing symptoms for a long time, the elimination phase often needs to last for several months or even 1-2 years in some cases. 

And I’m saying this as someone who really wants you to bring your favorite foods back! The goal is variety and abundance in your diet, but I also want to make sure we’re not skipping steps, because I want you to be able to eat those foods without feeling unwell. 

Because what’s important to understand is that many food sensitivities—especially if you have a lot of them and to nutrient-dense foods—are not about the foods themselves, they’re about immune system dysregulation, dysbiosis, and leaky gut. 

If you reintroduce foods while your immune system is still dysregulated and your gut is still out of balance, you will likely find that your reactivity returns. And the more you’re able to restore your immune system and gut health, the more foods you’ll likely be able to tolerate. We help people achieve this in our functional medicine telehealth clinic all the time. 

How To Reintroduce Foods 

Once you’re ready to start the reintroduction process, there are a few key things that can really help to improve your success. Here are my best tips for reintroducing foods without flare-ups. 

Start With the Most Nutritious, Least Suspicious Foods

I don’t often hear people talking about the order in which you should reintroduce foods, but this matters. It’s not the same for everyone, but try to select the foods that you feel are least likely to be problematic first, working your way up to the ones you suspect you may have reacted to in the past. 

Introduce One Food At a Time 

An elimination diet is in many ways a scientific experiment you’re running on yourself. The more you can focus on specific foods during this phase, the better. For example, if you introduce three different kinds of nuts in one day and then you experience bloating and constipation or other symptoms, you might think you can’t eat nuts at all, when really it’s just pistachios that are harder on your system. Similarly, stick to whole, pure forms of foods when evaluating them, rather than prepared foods that use them as an ingredient. 

Space New Foods Out By 3 Days

This is really important. Reactions to food aren’t always instant, and reintroducing foods too close together can create a lot of confusion around what’s actually triggering your symptoms. I recommend giving it at least three days so that you can be confident in your assessment of each food. 

Keep a Food Diary

Don’t try to keep track of everything in your head! Food journals, no matter how simple, can be so helpful when it comes to identifying patterns over time. Just log what you ate and how you felt, in any format that’s easy for you. 

Don’t Reintroduce Processed Foods

Depending on what your general eating habits looked like before your elimination diet, you may not want to reintroduce everything you’ve cut out. Elimination diets can kick off overall healthier eating for many people, and if you were previously consuming processed foods, refined carbohydrates, fried foods, sugar, and/or alcohol, this is a great moment to make a longer-term choice about keeping them out. 

READ MORE: 13 Inflammatory Foods You Need To Ditch Now, According To A Functional Medicine Expert 

Try to Limit Other Variables

During your reintroduction phase, the fewer other things you can change, the better. For example, introducing a new supplement in the middle of the process might skew your results. Of course, consider this within reason; context matters! 

Should you let an FST guide you, you could – not entirely but if you took one before maybe redo the test, it’s just more info 

Should You Test (or Retest) IgG Food Sensitivities? 

If you did a food sensitivity test prior to your elimination diet, you may want to retest at this stage. It’s not necessary, but it can be really helpful to get some more data on what’s changed during your elimination phase and where you’re at now. These tests are a snapshot in time, not an absolute or definitive guide to what foods are best and worst for you. 

READ MORE: Should You Get A Food Sensitivity Test? Here’s What To Know 

What To Do If You Experience Reactions or Symptoms 

First and foremost, don’t panic. I know that after spending months working on your health, it can be discouraging to experience a reaction when you reintroduce a food. Just know that this is an ongoing process, and your body may need a bit more time. Record your symptoms, leave that food out for now, and move on to the next food. 

Then, you can try reintroducing it again after a bit more time has passed. Try it in a smaller quantity first. Keep trying and testing. In many cases, you’ll be able to tolerate the food later. At the very least, most people are able to reintroduce lots of foods, if not all, after an elimination diet. 

In some cases, you may have a true sensitivity to a food, even when your gut and immune system are functioning well. If you feel great and are able to reintroduce most foods, but one or two keep triggering symptoms, this may be the case. 

Listen To Your Body During Reintroduction

There’s no single way to do an elimination diet. There’s a general framework, but at its core this is a personal experiment that involves tuning into your body and figuring out what works.

But even though it’s personal, working with an experienced practitioner can really help to simplify things. If you’re looking for guidance and support, consider reaching out to become a patient. Our goal is always to get to the root cause of your reactivity, and then get you enjoying as many delicious and nutritious foods as possible! 

As one of the first functional medicine telehealth clinics in the world, we provide webcam health consultations for people around the globe.

Sources

• Pastorello, E. A., Stocchi, L., Pravettoni, V., Bigi, A., Schilke, M. L., Incorvaia, C., & Zanussi, C. (1989). Role of the elimination diet in adults with food allergy. Journal of allergy and clinical immunology, 84(4), 475-483.
• Nanayakkara, W. S., Skidmore, P. M., O’Brien, L., Wilkinson, T. J., & Gearry, R. B. (2016). Efficacy of the low FODMAP diet for treating irritable bowel syndrome: the evidence to date. Clinical and experimental gastroenterology, 131-142.
• Poto, R., Fusco, W., Rinninella, E., Cintoni, M., Kaitsas, F., Raoul, P., … & Ianiro, G. (2023). The role of gut microbiota and leaky gut in the pathogenesis of food allergy. Nutrients, 16(1), 92.