This Fast Like a Girl review provides my professional opinion about the book Fast Like a Girl.
Fast Like a Girl is written by Mindy Pelz, a chiropractor and “nutrition and functional health expert.”
This book focuses on fasting, the act of not eating for extended periods of time in order to achieve… the healing of your cells and body. More specifically, she advocates for cycle fasting, linking your fasting patterns with your menstrual cycle for optimal results.
The beginning of her book has the disclaimer “not intended to replace personalized medical advice…author disclaims responsibility for adverse effects that may result from application of the information contained in this book”. This is followed by praise for the book including a long list of alternative medicine practitioners and celebrities, featuring the forward by LeAnn Rimes, a Grammy award winning singer, who unsurprisingly gives us a personal anecdote about how fasting helped her.
There is growing evidence in support of intermittent fasting. However, high quality scientific evidence is limited: much that shows benefit is from rat and other animal studies – these aren’t always reliably reproduced in humans.
Many of the human studies are quite small, and often done with the express purpose to addressing specific health challenges. Some longer, large, properly controlled studies have failed to show the benefits sought after with the diet. In the human trials that do show benefit, the fasting is supervised medically, with regular blood work and check-ins.
Finally, the concept of linking a fasting cycle with your hormonal cycle, to my research, doesn’t seem to exist anywhere outside of this book.
The introduction by Pelz tells us about her own personal experience with fasting and how it helped her hormones (how does she know this? Because she miraculously felt better after changing her diet).
We know that selling a service or protocol by introducing consumers to it through a personal anecdote, including celebrity endorsements, using popular buzzwords such as hormones, inflammation, and natural healing, is a red flag.
Attributing a sudden miraculous recovery from “chronic fatigue syndrome that made it impossible to do even the simplest daily life tasks”, to diet, because when the “depressive haze disappeared overnight”, this was a direct result the healing power of food, is a HUGE red flag.
This section goes on to blame most chronic diseases on metabolic syndrome, and her solution to “our current metabolic situation”, is fasting (a single cause for multiple complex issues = red flag).
She assures women they can “flip their metabolic switch” (this is a commonly-used claim that doesn’t make physiological sense and is more of a marketing ruse) through her program, but warns that “if a woman decides to jump into a fasting lifestyle and doesn’t time that fast to her menstrual cycle, adverse symptoms may appear such as hair loss, rashes, anxiety, missed cycles, thyroid problems, and trouble sleeping. These are all symptoms that can be avoided when a woman learns how to fast for her unique body”.
To me this screams unnecessary potential for great harm, but I’m just using common sense.
Pelz introduces her two made up food programs, called ketobiotic foods and hormone feasting foods (as if eating isn’t already confusing for the type of person who would buy this type of book, let’s go ahead and invent another couple diets).
She claims that in this book, we will find proven strategies, and condition specific protocols, because she is not selling a one size fits all approach. But I don’t see any reference to a clinical study where she would be able to actually prove her strategies at all; they seem like just her opinion.
The last section of the book provides a “30 day fasting reset”, which makes me cringe, because it’s so predictable: alternative health experts who use 30 days as the magic timeline for people to RESET *insert whatever they’re selling here*.
Just another red flag. Our bodies can’t be ‘reset.’
Fast Like a Girl PART 1
Along with introducing this section using Hippocrates and discussing how he used fasting as a primary healing tool in the 5th century B.C., (I would like to think we have evolved medically since that time), Pelz also highlights that fasting will “increase autophagy” (cell death). In this section, Pelz mentions a 2020 study about Covid-19 and claims fasting can help restore autophagy’s ability to shut down viral replication.
Unfortunately, this study is not referenced, the authors name(s) are not provided, and there is also no reasoning given as to why this is even relevant to the book. Pelz claims that “when you put your cells into both a state of autophagy and ketosis, [you are] creating an amplified healing state” and throughout this section of her book she lists physiologic processes preceded with words like “increases”, “decreases”, “resets” and “repairs”, to signal that fasting has a positive association with each one: “increases autophagy!”, “repairs the immune system!”, “Increases growth hormone production”, and the worst of all, “reduces the reoccurrence of cancer!”.
Throughout this section I found a lot of fancy sounding paragraphs attempting to link fasting as a cure for almost any complex ailment you can think of. The lack of directly cited evidence throughout this section is concerning; Pelz vaguely discusses such a range of complex topics it is difficult to believe someone could be an expert in so many areas and have the research background to discuss all of her claims with such assuredness, especially without the need for citations or references to high-quality studies to back them up.
She does have a bibliography by chapter in the back of her book, but without links to each claim, this makes it unbelievably challenging for readers to evaluate the studies she’s basing her opinions on. How do we know she’s interpreting things in a reasonable and scientific way?
Not all studies are created equal – a finding about diet restriction in 6 rats is not equal to a well-designed randomized control trial in hundreds of people. You can find a small study to show almost anything, but that doesn’t mean it’s reproducible, reliable or actionable for us.
I can’t stress enough the importance of practitioners to discuss topics that are within the scope of their area of practice. It is unclear what area Pelz is a qualified expert in. I guess “pioneer in the fasting movement” will do.
The language used surrounding much of Pelzs’ fasting protocols is alarming. Within the “autophagy fasting” length fasting of 17-72 hours, Pelz tells readers to think of autophagy as “this magical eraser that will undo the damage a poor diet created within your cells”, and this is after suggesting that a detox is necessary after a “vacation in which you overindulged”.
Is this a real science-based book? We can’t ‘erase’ food we’ve eaten, and to suggest that that’s possible is incorrect, not to mention disordered. We don’t even know enough about autophagy to make these sorts of claims.
The next few chapters describe clients who have had great results from adjusting their fasting windows and approaches to their menstrual cycle, and a large part of the chapter explains the rises and falls of key hormones women experience during this time.
There is a “small study of 15 women with PCOS” mentioned in here, which I was both happy and disappointed to see. Happy that a study was included (although not cited), but disappointed that Pelz seems to think a study with 15 participants over a short period of time would tell us anything useful or conclusive about anything. Maybe she should get a refresher on what high quality evidence means for her next book.
Fast Like a Girl PART 2
Once I got through part 1, which I would summarize as an advertisement for fasting, we move on to part 2.
In this section, we also learn that Pelz advocates for social media as a great source of health solutions, explaining that “the upside of social media is that you can teach yourself how to solve many of your health challenges”, and I am beginning to understand why Pelz’ YouTube channel is plugged so many times throughout this book.
There is a “toxic ingredients to avoid” list, including a common rule of thumb in the alternative health community, that “if you can’t pronounce an ingredient, chances are it’s a chemical”.
There is also a “foods that support estrogen” list, and one for progesterone, which I don’t understand, because there isn’t any evidence to suggest that broccoli supports progesterone, but cauliflower supports estrogen.
I think it’s great Pelz has included such a variety of nutrient dense fruits, vegetables, and legumes, but the credibility train stops when they are separated out into lists based on nothing but an idea.
There is a paragraph about avoiding animal proteins with added antibiotics and growth hormones, and to “always choose organic, non-GMO and antibiotic and hormone free foods wherever possible”. This messaging is so boring and just plain wrong.
Fast Like a Girl Fasting Cycle
The fasting cycle section of the book starts by saying that when you time your fasts properly you will “starve off disease”. This is certainly one way to market a fasting cycle protocol.
Pelz has created three phases within the fasting cycle, which coincide with a woman’s monthly cycle: power phase, manifestation phase, and nurture phase. She includes an anecdote about a woman who fasted improperly and lost her cycle, but then joined Pelz’ Reset Academy online, watched her YouTube videos, and was finally able to fast properly and got her cycle back.
Each fasting phase has a type of diet to follow (either ketobiotic, or hormone feasting), as well as a fasting window (either 13-72 hours for autophagy fasting, 13-15 hours for intermittent fasting, or no fasting at all during the “nurture” phase).
It is unclear if there is any real clinical data behind the phases Pelz has created.
It’s also important for me to say here, as a dietitian, that I don’t recommend that anyone fast for 72 hours. Or, for that matter, more than 16 hours. And some people shouldn’t be fasting at all, but more on that later.
I see how a plan or protocol to follow that is laid out with graphs and lists can seem appealing. Still, I can’t help but go back to the fact that through all this, we have lost or are in the processes of losing our abilities to listen to our bodies’ hunger cues and self-regulate.
Fast Like a Girl 30-day fasting reset and “Hacks” section
Here we learn that there is a two-week “pre-reset” leading up to the actual 30-day reset (that then sets the foundation for a lifetime of fasting cycles).
This is a lot of work for a non-evidence-based protocol. Who has time for this? And, a lifetime of fasting cycles? That sounds like hell.
Thankfully, Pelz assures us that “there are three easy parts to the pre-reset: foods to avoid, foods to add in, and compressing your eating window”. To me this means I am going to eat less often, and with more restriction.
“Foods to Avoid” lists are another red flag.
I am also encouraged to collaborate with my doctor before embarking on this new fasting lifestyle.
In the section about compressing the eating window, Pelz assures that “coffee and tea with a small amount of MCT oil and “clean cream” can work to kill hunger,” but advises that “if you like cream in your coffee, make sure if doesn’t have any chemicals or sugar in it as this will spike your blood sugar too much”.
Lastly, I can’t not highlight the utter insanity in the paragraph that follows the “clean cream”, where Pelz warns us to “watch out for food buddies: those women you have bonded with over food”. She goes on to give an example of an employee who lost a lot of weight by adopting a new lifestyle where friends who drank Frappuccinos regularly got the boot. Those friends became negative and disgruntled at the employee’s success, and the employees efforts were derailed and she gained the weight back.
I can tell you that the employee didn’t gain weight back because of her friends; in fact, lack of social interaction and friendship can be a reason for weight gain, not the other way around. Advising people to ditch friends over food is terrible advice.
This diet feels like the opposite of listening to one’s own body- women are instead instructed to ignore their desire to share food with “buddies” and listen to their hunger cues and are instead instructed to rely on Pelz’ opinion, which doesn’t seem to be rooted in clinical data.
We all apparently also need to get new friends who fast. That is ridiculous.
The opening line of a chapter in this section titled How to Break a Fast is “to eat or not to eat- some people think fasting is that simple”. I can’t stress enough that EATING can be this simple- and by NOT following a fasting lifestyle, you would be able to SIMPLY decide if you want to eat or not eat based on your bodies’ hunger cues.
Pelz goes on to tell readers that “as someone who loves to let the science guide me, I was left with little to go on and decided to do my own research. I turned to my community to see what worked best.”
Pelz is admitting here that she doesn’t actually do proper research; she just decides what works based on the outcomes from her own work, because she has “tested” on her own community of thousands of people. This is NOT how research works, and it proves a lack of understanding and huge bias in her work and her opinions.
Instead of suggesting we eat food when we feel hunger (because according to Pelz, “hunger is the elephant in the fasting room”), she suggests three hacks which I have summarised here: 1) am I hungry or am I bored? She suggests distracting yourself to find out. 2) if you are truly hungry and not bored, try a packet of minerals. 3) try a fasted snack such as an MCT fat bomb. 4) lastly, she suggests a prebiotic powder in water, coffee, or tea.
So if I feel hungry, I should try four different ways to ignore the messaging my body is sending me, instead of just eating a meal. This is an interesting spot to address the next topic: the very last page of this section discusses eating disorders.
Rather than advising anyone who has a history of disordered eating, or an ongoing eating disorder to NOT participate in fasting, Pelz states that “if you have an eating disorder you need to involve your doctor in the process of building a fasting lifestyle”.
Excuse me? How incredibly harmful. If you’ve ever had disordered eating at all, you shouldn’t go near any type of fasting.
Fast Like a Girl review, in short
I understand how appealing it can be for women to believe that a 30-day fasting reset followed by a lifetime of following a cycle of starving and eating with limitations will change their lives and waistlines, but I can’t stress enough how important it is to think critically whenever you come across books like this one.
This book checks all of the boxes used by every ‘functional alternative health expert’, including assigning words like clean or toxic to safe foods, mimicking eating patterns of primal ancestors (because they all lived to the ripe old age of ~30), imposing restrictions and rules to eating, encouraging women to ignore their hunger cues in the name of “starving off disease”, failing to provide high quality evidence for claims, and quite frankly, attempting to undo all the anti-diet work that so many of us are working so hard on.
It doesn’t empower women to give them more restrictive diets and unproven information about eating and their bodies. In fact, just the opposite.
I don’t ever recommend these types of self-healing diets, but if Fasting Like a Girl ever gets real clinical trial approval, and the results show that her protocol is safe and provides the results she claims it does, I will happily re-evaluate.