September 13, 2021

The Science Behind Whole30’s Success

The Science Behind Whole30's Success

Elimination Diets and the Whole30

You’ve heard us talk about the Whole30 as a 30-day “self-experiment” or “reset.” We use these terms to highlight the fact that Whole30 is not a weight loss diet and to help our community understand the spirit and intention of the program. In fact, the Whole30 is based on an elimination diet; the same framework many healthcare professionals consider the gold standard for identifying food sensitivities or adverse food reactions.

However, the Whole30 takes an elimination protocol one step further by combining the benefits of an elimination diet with the science of behavior change, helping you reconnect with your body, improve your relationship with food, and build self-efficacy. The program resources also provide guidance around exactly how to take what you’ve learned during the program to create the perfect, sustainable diet for you, which we call your “food freedom.”

Our original tagline said “let us change your life,” and many Whole30’ers report the program truly is life changing beyond just their dietary habits, spilling over into their personal growth, exercise routines, relationships, career and more. You can see evidence of this spill-over effect throughout our database of Whole30 testimonials.

> Lindsay put her Hashimoto’s into remission

> Colie had energy for earlier and more productive mornings 

> Brian started practicing yoga and running in 5k races

In this resource, we’ll cover the history and science of elimination diets, the details of Whole30’s specific protocol, and exactly how the program works to provide such dramatic transformations in just 30 days.

What is an elimination diet?

The concept of the elimination diet was first proposed by Dr. Albert Rowe in 1926. Since then, it’s largely been regarded as the gold standard for identifying food sensitivities. Elimination diet protocols can be a highly effective and useful low-cost tool to identify food sensitivities and intolerances. Examples of elimination protocols you may have heard of include the low-FODMAP protocol and AIP (autoimmune) protocol.

An elimination diet is a dietary protocol that intentionally omits a specific food or group of foods that are believed to cause adverse reactions in the body. This elimination period lasts for a specific period of time, often 2-6 weeks. The elimination period allows the body to heal and repair. During the elimination protocol you are:

  • Removing food components/proteins that may be causing issues
  • Healing your gut 
  • Calming your immune system (systemic inflammation)
  • Restoring healthy metabolism/blood sugar regulation

After the elimination period, there is a structured reintroduction period where foods that were eliminated are reintroduced one at a time, every 3-4 days. This process helps identify if certain foods trigger negative responses at certain doses.

What is the Whole30?

The Whole30 is a structured elimination protocol. During the elimination phase, participants omit added sugar, alcohol, grains, most legumes, and most forms of dairy for 30 days. During the 10-14 day reintroduction, participants reintroduce each food group one by one to determine whether or not they contribute to negative symptoms. (Following reintroduction, Whole30 offers guidance on using those learnings to create a personalized and sustainable food freedom plan.)

As with other elimination diets, the Whole30 is not recommended to be followed long-term. It is used to help an individual customize a nutrition plan that works for their unique body, based on the knowledge gained during elimination and reintroduction.

Think about the Whole30 like a science experiment:

  1. You have a hypothesis that certain food(s) you’re eating may be contributing to symptoms
  2. You do the Whole30, eliminating foods that are commonly problematic for your symptoms
  3. You then reintroduce the foods you’ve eliminated, and compare how you feel
  4. You apply the information you’ve gained from the experiment to your food freedom

What are the benefits of the Whole30?

Elimination protocols eliminate foods that are commonly known to cause inflammation or symptoms such as GI distress (bloating, gas, constipation, diarrhea), skin irritation (eczema, psoriasis, acne), headaches or migraines, seasonal allergies, brain fog, anxiety, fatigue, and joint pain or swelling, among others. The Whole30 also eliminates foods that commonly contribute to sugar cravings and a dysfunctional relationship with food.

For other potential benefits, check out the Whole30 non-scale victory handout

The process not only helps you identify the foods that may be having a negative effect in your body, it can also bring about general improvements in energy, sleep, focus, mood, and self-confidence. The program is designed to reset your “normal,” giving you a new baseline for what it means to feel good and perform optimally.

Why are elimination protocols so strict?

In order to accurately determine how certain foods are impacting your health, you need to completely eliminate them for the prescribed period of time. Only complete elimination allows your gut, immune system, and other body systems to heal or calm, bringing about improvements in any number of symptoms, and such that it’s easier to notice the return of those symptoms during the reintroduction period. 

Even small amounts of foods to which you are sensitive can disrupt the “reset” you’re trying to accomplish. Including these foods on weekends or special occasions can slow down the healing process, making it hard or impossible to see clear improvements, or identify issues during reintroduction. To make the most of your Whole30 “scientific experiment,” completely eliminate all of the recommended food groups for 30 straight days, then reintroduce carefully and systematically, one food group at a time.

What’s so special about 30 days?

The elimination portion of the Whole30 is 30 days for a few reasons. First, thirty days is long enough to see dramatic improvements, but not too long for it to feel overwhelming. Habit research says it can take anywhere from 18 to 254 days to make a habit “stick,” depending largely on how emotionally tied you are to that habit. Creating new habits with food can be an emotional challenge, but asking someone to follow a strict elimination protocol for eight months isn’t reasonable. In our twelve years of clinical experience, we’ve found 30 days is the sweet spot; long enough to see dramatic, life-changing results, but short enough to feel attainable. 

What’s the difference between a food sensitivity and an allergy?

When an individual has a food sensitivity (sometimes referred to as a food intolerance), it means their body has a hard time processing or digesting components (often a protein or sugar) within the food. An example of a common food intolerance is lactose intolerance, where an individual has a hard time digesting the milk sugar lactose, and may experience bloating, gas, stomach pain, and/or diarrhea. With food sensitivities, the body’s response can happen after eating, but could also be delayed. This means you may not notice symptoms for up to three days after consuming the food.

This is different from having a food allergy, which impacts about 10.8% of U.S. adults and 7.6% of U.S children. With a food allergy, the body’s immune system reacts to a food or a substance in the food, identifying it as potentially harmful and creating antibodies to fight it and protect you. This response is known as an IgE and/or histamine response. It’s often immediate (within two hours after eating the food) and can be life-threatening, such as in the case with peanuts causing anaphylaxis. 

With a food allergy, the definition and diagnosis is clear. Individuals should work with their healthcare provider if they think they have (or are currently navigating) a food allergy. Food sensitivities have no standard medical definition and are sometimes referred to as food intolerance, IgG, or IgA response.

Can’t I just take a food sensitivity test?

You may have heard friends or family members talk about a “food sensitivity” test they did at home or with their provider. For some, this test can provide helpful direction towards customizing their elimination diet protocol. For others, it can do more harm than good. In fact, organizations including the American Academy of Allergy, Asthma and Immunology and the Canadian Society of Allergy and Clinical Immunology have recommended against using IgG testing to diagnose food intolerances and sensitivities.

IgG-based food sensitivity tests have not been proven to identify food sensitivities, and often have false positives. Intestinal permeability or frequent exposures to a food can result in multiple foods being erroneously flagged as “culprits” (foods to which you’re sensitive). This can result in unnecessary and sometimes excessive restrictions. In addition, these tests can be expensive, and therefore aren’t accessible to all. By contrast, elimination protocols such as the Whole30 offer a free, clear, and effective way to assess which foods may be contributing to symptoms in your body.

Why does the Whole30 eliminate _____?

It’s important to note that the Whole30 doesn’t eliminate foods because they’re “bad.” There are no universally good or bad foods. The Whole30 eliminates food groups that have been shown in the scientific literature and our clinical experience to be commonly problematic (to varying degrees) across a broad range of people. 

Some foods eliminated during the Whole30 (like dairy, wheat, peanuts, and soy) are four of the top eight food allergens. Other food groups are eliminated due to the potential  impact they might be having on your digestive system, metabolic health, inflammation, and cravings. Let’s take a closer look:

Why Does the Whole30 Eliminate Added Sugar?

From a nutrition perspective, few people will argue with the benefits of limiting added sugar. When overconsumed, added sugar has been demonstrated time and time again in scientific literature to have a negative impact on cravings, blood sugar regulation and metabolism, digestion and gut health, and systemic inflammation. While artificial sweeteners like saccharin or aspartame aren’t believed to promote blood sugar dysregulation to the same degree as natural forms of sugar, they can contribute to headaches, migraines, irritability, increased sugar cravings, gas and bloating. While we’re not classifying sugar in any form as “bad,” leaving all forms out for the elimination portion of the Whole30 will help you identify which forms of sugar, at what amounts, and in what context work best for your body.

Why Does the Whole30 Eliminate Alcohol?

Similar to added sugar, it’s not much of a stretch to understand why we eliminate alcohol for 30 days on the Whole30. Overconsumption of alcohol has been shown in a variety of literature to have a deleterious effect on cravings (and is an addictive substance), blood sugar regulation and hormonal balance (particularly sex hormones), gut health, and systemic inflammation, particularly impacting the nervous system and brain. For all of these reasons, and the fact that alcohol inhibits good judgment around food choices, the program eliminates all forms of alcohol, even for cooking, for 30 days.

Why Does the Whole30 Eliminate Grains?

There are different protein structures in grains that have been found to create transient increases in gut permeability. These problematic proteins are particularly resistant to digestion, meaning they arrive in the gut largely intact. They can improperly cross the gut barrier, and may allow other substances (like incompletely-digested food particles, bacteria, or viruses) through the gut and into the body, all of which triggers an immune response and promotes systemic inflammation. You may be familiar with one protein component of wheat, rye, or barley called “gluten,” but non-gluten grains like corn or pseudo-cereals like quinoa contain other proteins which may be similarly irritating.

Inflammation can also be the result of impaired metabolic health or blood sugar control. When grains are consumed in excess, especially refined versions, an individual may have a harder time keeping their blood sugar within a healthy range. Replacing grains with vegetables and fruit for 30 days can improve both metabolic health and blood sugar regulation dramatically.

Why Does the Whole30 Elminate Legumes?

There are many properties in legumes and lentils that make them a nourishing food for the gut and for overall health, especially when they’re prepared in ways that make them easier to digest, such as soaking and sprouting. But for some, specific carbohydrates in beans and lentils can cause GI symptoms like gas,  bloating, and indigestion. Soy and peanuts also fall into this category; both are commonly allergenic foods.

Why Does the Whole30 Eliminate Dairy?

You may already be aware if dairy doesn’t sit well with you. You could be part of the 60-70% of the global population that has lactose intolerance, or someone who notices a strong correlation between dairy consumption and skin issues like acne or eczema. 

In some individuals, the components of dairy (particularly casein, whey, and lactose) may contribute to digestive issues like gas, bloating, or stool changes; skin issues like eczema, hives, and acne; seasonal  allergies and congestion; and asthma. Symptoms may arise soon after eating a food that contains dairy (cheese, milk, yogurt, ice cream, latte) or up to three days later. For these reasons, we eliminate all forms of dairy but clarified butter or ghee (which have no lactose or milk proteins) for your Whole30 elimination.For more of the background and science behind the food and beverage groups we eliminate on the Whole30, refer to our first book, It Starts With Food (2012).

What does Whole30 reintroduction look like?

During Whole30 reintroduction, you’ll be bringing back added sugar, alcohol, non-gluten grains,  gluten-containing grains, legumes, and dairy one food group at a time, returning to the Whole30 for 2-3 days between groups. This allows you to effectively evaluate the impact each food and beverage group may be having on your body, while allowing negative symptoms that may arise in a given group time to calm before reintroducing the next group.

In our official schedule, you’ll reintroduce groups in the order of “least likely to be problematic” to “most likely to be problematic” based on our clinical experience. (That’s why we’ve broken out gluten grains from non-gluten grains.) However, you are free to reintroduce food groups in your preferred order, as long as you’re only reintroducing one at a time,  and returning to the Whole30 for 2-3 days between groups.

For more on our “fast track” reintroduction schedule, sample meals, and what kinds of symptoms to look for during reintroduction, refer to the Whole30 reintroduction page on our website.

Is There Clinical Evidence To Support The Whole30 Program?

In 2018, Catherine Moring, PhD, RDN, BC-ADM, CDCES, who is Executive Director of the James C. Kennedy Wellness Center in Mississippi, conducted a pilot study with 45 Whole30 participants and shared her results with us. Dr. Moring and her team provided education about the side effects of chronic inflammation, the benefits of an elimination diet, and the Whole30 Rules and Recommendations. They also supported participants by teaching them how to prepare and enjoy minimally-processed, whole foods without focusing on calorie counting or food restriction.

Dr. Moring’s team collected bloodwork and biometrics from the 45 study participants before and after completing a Whole30. Although the results of this cohort study have not yet been peer reviewed or published, Dr. Moring shared this overview of the outcomes with us.

  • The average decrease in overall cholesterol was 13.37
  • The average reduction in triglycerides was 24.57
  • The average reduction in LDL (“bad”) cholesterol was 6.33
  • The majority of participants (70%) experienced lower blood sugar
  • Participants reduced their average blood glucose level by 2.34 mg/dL, from slightly impaired to within normal limits
  • An estimated ⅔ of patients had lower blood pressure after Whole30
  • The average participant BMI decreased by 2.36 points, along with an average waist circumference reduction of 3.01 inches and an average weight loss of 12.11 pounds

Dr. Moring reported that several participants in the study were able to reverse pre-diabetes. Several others with diabetes were able to reach blood glucose targets. One participant was able to stop taking insulin by the end of their Whole30.

Other non-scale victories reported by Whole30 participants in Dr. Moring’s cohort study included improved digestion, clear skin, better sleep, fewer medications needed, more energy, less anxiety and depression, reduced pain, improved focus, better moods, and increased self-confidence.  Along that same line, our own internal data (unpublished) also showed that in 2022, a small focus group of Whole30 participants experienced a 13.4% increase in positive body perception on the clinically validated Body Appreciation Scale.

What happens after the Whole30?

Any elimination protocol, including the Whole30, is meant to be a short-term experiment. The Whole30 is not prescriptive, in that we don’t believe everyone needs to (or should) eliminate all of these food groups forever. After elimination and reintroduction, participants will have a well-established road map of which foods work well in their system, and which do not. Using our follow-up book Food Freedom Forever, Whole30 alumni will use their Whole30 knowledge to create their own healthy, sustainable, personalized diet (what we call their “food freedom”). Most choose to continue to eliminate foods they don’t tolerate well (or only include them in certain contexts or limited amounts), while continuing to eat foods they’ve discovered work well for them. Everyone’s food freedom looks different, as it is based on each person’s unique experience with the Whole30.

We hope this explanation helps you better understand the foundation of the Whole30 program, the basic tenets of an elimination diet, and how the Whole30’s framework helps you truly rest your health, habits, and relationship with food. Our mission is to empower you to own your health and change your life, and we invite you to join the millions of people around the world who have used the Whole30 to achieve lasting food freedom.