top of page

"Intuitive Fasting": What do Dietitians Need to Know?

Dietitians are (understandably) in an uproar about a new book called Intuitive Fasting. What do you as a nutrition professional need to know in order to advocate for evidence-based wellness and well-being?

A new concept called “intuitive fasting” entered the wellness world recently. You can probably guess what it entails just from the name -- it’s the latest popular diet plan, combining intermittent fasting with intuitive eating, or rather, not eating. So, what should dietitians be aware of when it comes to intuitive fasting?

This diet plan is potentially problematic in many ways, but we will focus on three troubling areas. The main concerns about this recent fad diet are: 1) It is mainly endorsed by celebrity doctors, nutritionists, and “wellness gurus” 2) it centers around the “brand new revolutionary” concept of metabolic flexibility and claims that three meals a day can cause “metabolic inflexibility” 3) and finally, it fails to account for the fact that fasting is not an intuitive practice.

Read on to learn more about how to handle this hybrid diet and for tips and tricks to use when patients come to you with questions.

A Bit of Background

Intuitive Fasting is a book written by Dr. Will Cole. According to Amazon, it was released one week ago, on February 23, 2021. Already the #1 Best Seller in Weight Loss Diets, the book has dietitians up in arms, and understandably so.

Essentially, the diet plan has gained great attention even though the main “experts” have little to know training in diet or nutrition. Part of the reason this diet plan has quickly become renowned is that Gwyneth Paltrow is a staunch advocate of Will and his healing prowess. In fact, Paltrow herself wrote the foreword and the book is made available through Goop Press, a book imprint of the lifestyle brand Goop.

Let's tackle this trend with THREE TRUTHS.

Truth #1: “Wellness Gurus” are not Nutrition Experts.

Let’s first take a look at the Author, Dr. Will Cole. Taken straight from his website, here’s what we know about him:

  • He is not a medical doctor. Beyond not being trained as an expert in nutrition, Dr. Will Cole doesn’t even have expertise in conventional medicine. He is a chiropractor, natural medicine doctor, and functional medicine practitioner. Essentially, he trained in functional medicine and clinical nutrition but -- quoting straight from his website -- he does “not practice medicine” and does “not diagnose or treat disease or medical conditions”.

  • He is not a nutrition expert, yet he explicitly and regularly promotes “working closely with functional medicine experts so they can help you identify the right diet” for diets like the Specific Carbohydrate Diet (SCD). Instead, purposely confusing and vague terms like “detoxes”, “natural healthcare”, “holistic approaches”, “recharge metabolism”, and “renewed cells” are used to distract consumers and describe outcomes without offering evidence. A real expert, like Kim Braly RD, specializes in helping patients achieve remission through the SCD using research. This research is clearly referenced and easy found, both on her “What is Dietary Therapy?” page, as well as through the extensive research articles available on her blog.

If Doctors aren’t receiving adequate nutrition education, Dr. Cole the Chiropractor isn't either

These points make Cole’s book terribly concerning, considering that a recent study found the following:

“Only 14 % of American physicians report that they feel adequately trained to provide nutritional counselling. The average number of nutrition teaching hours in American medical schools is falling below recommendation...many medical not reach the minimum required hours (25-44) as set by the National Academy of Sciences and the American Society for Nutrition.”

Yet another more recent study yielded the following insights:

the majority of medical schools offer very little to no training or education in nutrition to medical students during their tenure in medical school...medical students and physicians agreed that the nutrition education currently provided in medical school is inadequate. Residents stated they would benefit from further training in behavioral counseling in order to increase their confidence in educating patients about nutrition. Increasing training in these areas could translate into improved health outcomes.”

I always say, three establishes a pattern -- so here is a third study, conducted within the past two years to show it remains a significant problem:

“A rising incidence of chronic health conditions with a nutrition background (e.g., obesity, cardiovascular disease, type 2 diabetes) has led to an even greater need for nutrition educational content in medical school curricula...students beginning medical school are lacking formal nutrition education, as only 8% arrived with some form of exposure. Despite this, nearly 85% of these medical students recognized that nutrition education is necessary in their training, and 70% state that the nutrition education they have received has influenced the way they care for patients.”

To be clear, I absolutely believe that conventional medicine is necessary. I respect doctors and recognize them as experts and essential members of a multidisciplinary team. However, when it comes to nutrition, dietitians are the experts.

Cole’s Lack of Qualification and Credibility are a Major Concern

If medical doctors aren’t adequately trained in nutrition, what qualifies a chiropractor who studied natural and functional medicine to do so? The answer is it doesn’t. Books like Intuitive Fasting often do more harm than help in that they inappropriately occupy a space in which dietitians have a clear and defined scope of practice.

In fact, research shows that primary reasons nutrition care is an important yet ignored role in medicine include poor application of nutrition science (such as in popular nutrition books written by non-nutrition professionals) and poor collaboration with nutrition professionals. I find it incredibly concerning that not one dietitian is quoted in praise of the book Intuitive Fasting -- check Dr. Will Cole’s website to see for yourself.

To learn more about what academic and professional requirements dietitians meet to become and remain food and nutrition experts, you can read the Academy of Nutrition and Dietetics’ article Qualifications of a Registered Dietitian Nutritionist.

An important note -- anyone can call themselves a nutritionist, but the term dietitian is protected by law. Be wary when working with nutritionists, and be sure to ask what their qualifications are beforehand to ensure the best standard of care is being practiced.

Truth #2: A well-nourished body has a balanced metabolism and is capable of flexibility all on its own -- no fasting necessary.

The world “metabolism” seems to be one of the most charged in the diet and nutrition industry. We discourage against vilifying foods as “bad” or “good”, yet the diet industry is ripe with ads preying on poor or bad metabolisms, claiming to reverse and establish great metabolisms in their place.

Defining Metabolism & Metabolic Syndrome

According to the Academy of Nutrition and Dietetics, “Metabolism is the process by which our bodies concert what we eat into the energy we need to survive and function.” In other words, what we eat powers our bodies and helps us to maintain a healthy weight.

Metabolic functioning refers to the body’s normal biochemical processes. When these processes are disrupted, metabolic syndrome can result.

Metabolic syndrome is the name used for a group of risk factors that increases the chances of heart disease, chronic disease, and other serious health conditions. Insulin resistance plays a key role in metabolic syndrome and may increase the risk of developing metabolic disease.

What the Evidence Shows

In a nutshell, insulin is a hormone that regulates the amount of nutrients circulating in the blood. It mediates the uptake of blood sugar by cells.

Reliable studies on the relationship of insulin resistance and intermittent fasting are hard to find, let alone any on “intuitive fasting”. Studies that claim to establish significant associations have few patients and it is likely that the researchers double as authors and disclose profits from their books sales which promote alternate-day fasting (ADF) or intermittent fasting.

In one study, effects were considered “long-term” if they lasted for a 10-day fasting period. These studies often have a high dropout rate and factors, such as receiving food or counseling, are poorly controlled for across the groups being studied. This makes it irresponsible, and some would argue even unethical, to generalize and popularize the results as effective therapies.

While animal studies can’t be directly translated to human biology, they do help illustrate potential dangers and make scientists more aware of the research that is still needed, especially since studies on fasting are often unethical due to the measures participants would endure for results.

A recent study on animal models showed the potential dangers of intermittent fasting on metabolism. While the results of this study showed body fat decreased through intermittent fasting, it also showed that metabolism was compromised and insulin resistance exacerbated.

The most conclusive result that can be drawn on ADF or intermittent fasting is summarized nicely in a recent Harvard Health article:

Usually at this point we say something like ‘more studies of this approach are needed,’ but I won’t. There’s already plenty of evidence supporting a common-sense lifestyle approach to weight loss: ample intake of fruits and veggies, healthy fats, lean proteins, and plenty of exercise. From apples to zucchini, there are over a hundred ‘real’ foods you can eat endlessly, enjoy, and yes, still lose weight.

I would advise against spending any more money on fad diet books.

Why Intuitive Fasting isn’t a “Brand New Revolutionary” Idea for Metabolic Flexibility

It’s not uncommon that a slow or lagging metabolism is blamed for weight gain. However, an unsupported metabolism is more likely the culprit. How to support your metabolism?

The claim that “intuitive fasting”, which is at its root planned or scheduled calorie restriction, can recharge weight loss and health is a dangerous notion. Low calorie diets and skipped meals can trigger systemic survival instincts in the body. What does this do to the body?

The body adapts to calorie limitation by going into survival mode -- essentially, the body takes that input to mean it must find a way to do more but with a lesser amount of calories.

Evidence-based studies looking at metabolic sensitivity or syndrome emphasize education about making healthy and wholesome food choices to be a vital aspect of remission and recovery. Our bodies are incredibly resilient, and they are designed for adaptation to and protecting us from difficult circumstances.

Intermittent and so-called “intuitive” fasting hinge on the metabolic switch from using glucose as a fuel source to using fatty acids and ketone bodies as fuel. These ideas are developed using short-term data and often ignore significant scientific evidence that delayed eating increases the risk of overeating and binge eating episodes. The established evidence says it best: “Regular eating, not intermittent fasting, is the best strategy for a healthy eating control”.

Wellness is about what we are eating, not about fasting

The bottom line is there is not enough evidence to prompt “intuitive fasting” as a responsible practice or therapy -- for any group. The human body, when properly nourished, does an excellent job in finding balance and being adaptable to life’s circumstances. It’s about what we are eating, not that we are eating instead of fasting that exacerbates illness.

With metabolic disease, the Academy of Nutrition and Dietetics advises, “you can take action”. Fasting, as part of any plan, is not evidence-based enough to be prescribed. Currently, many dietitians consider it a form of disordered eating pattern (when practiced outside of established religious observance), and a type of inaction disguising as “intuitive wellness”.

If wellness were intuitive, we wouldn’t need health professionals. We may know how our bodies work practically, but the experts help us function on a biochemical level. The book Intuitive Fasting is nutrition speculation based on a chiropractor’s recommendation.

Truth #3: Fasting is not an intuitive practice.

One of the main tenets of intuitive eating is honoring your hunger -- just take it from the Intuitive Eating Pros (dietitians Evelyn Tribole and Elyse Resch): “Once you reach the moment of excessive hunger, all intentions of moderate, conscious eating are fleeting and irrelevant”.

Research as recent as within the last year confirms that fasting is not established as well-studied, safe, or feasible for human lifestyle management. Meta-analysis and systematic reviews, which take into account databases of evidence, show that intermittent fasting and energy restrictive diets have no meaningful effect on body measures such as cholesterol.

Even more horrendous and harmful, restrictive patterns are associated with suicidal ideation in youth.

Intuitive eating, on the other hand, “predicts better psychological and behavioral health across a range of outcomes”, says findings from an eight year study evaluating unhealthy weight control behaviors, such as fasting or skipping meals, and disordered eating.

There is nothing natural about fasting. Our bodies are triggered to survive by fasting, not thrive. Even in religious circumstances, fasting is considered in most cases to be a method of mastering the natural feelings of hunger in order to evidence to a higher power an elevated level of obedience. Often, these rituals or practices are short-term observances, and spiritual leaders acknowledge that health considerations can be made to determine whether or not an individual should participate.

The Bottom Line on “Intuitive Fasting”

As one study looking at scientific evidence for weight loss diets put it so aptly, “Food quality matters in a weight loss diet aiming to promote health” and “to date, no optimally effective weight loss diet exists for all individuals”. The experts do not predict fasting as the future of dietary therapy. Rather, an tailored approach to dietary prescriptions with a respect to religious reasons for fasting is recommended.

General advice from a “wellness guru” is not recommended to meet your unique, individual needs. It’s important to communicate to patients, clients, and yourself that eating nourishing foods is the most intuitive practice out there. Honoring hunger and fullness while continuously learning how to optimally fuel yourself with food is just about as human as it gets.



Ellis E. 3 Steps to Help Combat Metabolic Syndrome. Published February 16, 2021.

Gunnars K. Insulin and Insulin Resistance -- The Ultimate Guide. Published July 24, 2019.

Hoddy, K.K., Marlatt, K.L., Çetinkaya, H. and Ravussin, E. (2020), Intermittent Fasting and Metabolic Health: From Religious Fast to Time‐Restricted Feeding. Obesity, 28: S29-S37.

National Heart, Lung, and Blood Institute. Metabolic Syndrome. Accessed March 2021.

Saklayen, M.G. The Global Epidemic of the Metabolic Syndrome. Curr Hypertens Rep 20, 12 (2018).

Wolfram T. 4 Metabolism Myths and Facts. Published April 30, 2019.

bottom of page