Intermittent fasting has been around for several years, but like all diets, they tend to recycle themselves. Now it appears IF is all the rage again! It’s popular for those who want to lose weight and “feel better/ healthier.” Some even claim that fasting will prevent diabetes, cancer, Alzheimer’s and heart disease. Fans of IF declare it to slow the aging process and decrease inflammation.

When researching for this article, I met some folks that seem to be doing IF for legit medical reasons: they have Lyme disease and are helping to heal a “leaky” gut or other GI conditions. These folks are not interested in weight loss per se, but in actually improving specific health indicators as well as more immediate relief from various symptoms. The majority of folks doing IF however are likely doing it for superficial reasons such as weight loss, and or more ambiguous reasons such as to “feel better,” or “be more productive.”  

What is Intermittent Fasting (IF)?

There are a variety of different types of fasts to choose from, which is somewhat confusing. Generally, fasting dictates that you to eat within a “window,” typically 8 hours and then fast for the other 16 hours. Another type of fast is the 5:2, which means you eat “normally” five days per week, and then fast for two days where you eat only 500-600 calories per day. Others fast for 24 hours once or twice a week. It’s not rocket science to understand that fasting forces calorie restriction by self imposing time limits on when you can eat as well as forces you to skip entire meals, thereby reducing total calorie intake.

What does the research say about IF?

Most of the research on intermittent fasting (IF) has only been studied on animals- RATS (we are not rats). And, this will come as no surprise, that the majority of studies on IF include calorie restriction, which most always produces short-term weight loss (shocker!)

There are a few studies done on men with type 2 diabetes. These studies looked primarily at indicators of health, such as glucose levels, rather than actual health outcomes, like diabetes. Many of these studies only lasted a few months. According to Howard Steiger, a professor of psychiatry at McGill University: “There hasn’t been a long-term study establishing that intermittent fasting has good outcomes.” There are only short-term improvements in markers of inflammation, reduced glucose levels and fatty liver improvements.”

There have been some studies in women and the focus is always on weight loss without reporting any detrimental changes in hormones or mental health. Theses studies are small sample sizes as well as short-term studies, making it impossible to predict positive long-term health outcomes.

Most of what you hear in mainstream media, will only report the positive benefits of IF. And in our health obsessed diet culture, it’s no wonder we only hear the inflated benefits. The reason for this is that journalists and media folks are generally not trained nor is it their job to critically examine research studies. They have deadlines to meet and magazines to sell. They often cherry pick positive results out of context and spin it around to grab your attention. Their job in our capitalistic money driven system is to sell their stories. Roger that.

“Want to turn back the clock on aging…? Avoid all future health problems AND lose weight fast?”

Headlines like these grab your attention and prey on our collective anxieties and vulnerabilities. Let’s face it: no one really wants to talk about aging or what they think they might die of? Alzheimer’s? Inflammation? Cancer? No thanks; let’s distract ourselves from feeling any kind of discomfort about death, wrinkles or grey hair. Let’s shift the focus towards how we can CONTROL our lives instead! That sounds like way more fun to me!

The good news is that you are already fasting!  

Our bodies already naturally fast when we go to sleep at night. Fasting gives our digestion a break and resets our gut and hormones involved in appetite regulation. Say for example you eat dinner at 7pm, go to bed and then sleep a solid 8 hours (ideally!), you wake up and will likely have breakfast between 7-9am. This is a 12 hour fast. When we eat breakfast in the morning, we are indeed breaking the fast.

The great news is that we still reap the metabolic benefits from fasting in twelve hours. In my opinion, it’s just not necessary nor worth it to go to the extremes that IF requires.

The problem with Intermittent Fasting.

Intermittent fasting is just not sustainable long term for the majority of people. Sorry to burst our longevity bubble. As promising as some of these new studies on humans are, unfortunately, we just do not have evidence that IF will prevent the outcomes of all of the major diseases that we will all eventually die from.  

The main problem with fasting is that it’s hard for most people to stick with over long periods of time. Fasting for up to 16 hours per day requires that one disconnect from their body. They must suppress, ignore and fight off their physical hungers. This is not natural and it is certainly not intuitive eating. Ignoring your physical hungers is as natural as suppressing your urge to go to the bathroom. Furthermore, when we suppress and ignore our physical hungers for longer periods of time, this causes our stress response to kick in. This causes an increase in cortisol, a major stress hormone that increases food cravings as well as inflammation. Isn’t your body smart? It’s doing this on purpose to get you to eat something so that you aren’t so stressed out, irritable and grumpy. Your body’s only job is to keep you alive; it doesn’t care if you want smaller thighs, a six-pack (not beer!) or whatever.

IF is a set up for over-eating and binge eating. Not good!

It’s not uncommon for dieters to adopt all-or-nothing thinking patterns. The common trap for dieters is called the diet-binge cycle; whereby dieters are good (fasting), and then they are bad (eating like crazy). Fasting causes low blood sugars that result in extreme hunger and subsequent food cravings. Add some stress and tension from deprivation/restriction into the mix, and you’ve got a recipe for the perfect binge! (Which can be it’s own ‘high’ for some!)

We have lots of research to support that energy/calorie restriction for most people results in: increased fatigued and feelings of hunger, worsens moods, heightens irritability, impairs concentration, and leads to increased fears of losing control around food. All of these symptoms are common among those that suffer with eating disorders. IF is indeed then a gateway drug to developing more serious disordered eating behaviors.

Extreme hunger always drives over eating, because you can’t trick the body for too long. The body’s natural response to starvation and extreme restriction will inevitably cause rebound overeating. Most folks will re-gain any weight they lost and an additional 10 % more from when they first started. So, unfortunately, IF is not sustainable for most dieters, and can increase the likelihood of weight gain over the long term. Even fasting for ‘medical or health’ reasons is contraindicated for those with a history of eating disorders and disordered eating as it will activate those same centers in the brain, likely causing relapse.

Dieting is the #1 risk factor in the development of any eating disorder. 

The majority of people I interviewed for this article told me that IF made them feel ‘awful.’ That fasting for long periods of time caused such a drop in blood sugar resulting in serious: “grogginess, dizziness, headaches, irritability, fatigue, and dehydration.” One woman said it made her adrenal fatigue worse and that her health still suffers from the effects of her IF experience.

To be fair, there were a handful of folks that reported they ‘loved the feeling of fasting,’ and that it made them have more energy and feel more ‘productive.’ With all the variations in the different types of fasts, it’s impossible to know exactly what and how much each person is doing to achieve these results. This is why human nutrition is so hard to study. People generally have a hard time recording their foods accurately, and or and are unreliable as far as self-reporting is concerned.

Some folks that love IF, report a “high” or euphoric feeling. From an evolutionary perspective, this “high” is likely an adaptive response from starvation to ensure survival of our species as we become more “high” and motivated to seek out food. It also relates to ketosis, which happens when one severely restricts carbohydrates causing suppression of appetite. In case you were wondering, these very low carb diets are also not healthy or sustainable long term. And, for those of you thinking, “So and so does fasting and it seems to be working for them long-term.’ My unpopular opinion here is that they likely have a chronic type of ‘disordered eating’ and that their IF ‘lifestyle’ dominates most everything they do in life and consequently limits their freedom and joy in life as well.

Productivity, Bio hacking, and Control………………………….. Let’s please not forget: We live in Diet culture!

Proponents of IF can be very convincing. But really, it’s just another trendy diet promoting disordered eating under the guise of ‘wellness.’Productivity, bio hacking, and control are buzzwords in various online communities that glorify intermittent fasting. According to Dr. Cynthia Bulik, the director of the Center for Excellence for Eating Disorders at the University of North Carolina,“People who have extreme eating behaviors (intermittent fasting, bio hacking, extreme pickiness) can have variants of anorexia nervosa or avoidant restrictive food intake disorder (ARFID) and go undetected because they are packaged as healthy or productivity-promoting.”

Intermittent fasting is a glorified trendy form of disordered eating.

IF is a diet in disguise!

If it walks like a duck and quacks like a duck, then it is a diet. Intermittent fasting is just another culturally normative diet cloaked in buzzwords such as “wellness” and “productivity.” Like all diets, there are rules of when you can and can’t eat, and we know from overwhelming research that diets are NOT sustainable long term and will eventually be abandoned. Bummer!

Why is our culture so OBSESSED with being “healthy?”

Dieting for the majority of folks is a great way to distract and cope with and from existential anxiety, anti-aging anxieties and other areas in our lives where we have no sense of control.

“Never underestimate the inclination to bolt.” – Pema Chodron

What Buddhist teacher Pema Chodron means by, ‘never underestimate the inclination to bolt,’ is that humans are really bad at sitting with discomfort (in general). We just aren’t good at identifying and sitting with our emotions- especially that more ambiguous ones such as fear, anxiety and grief. Dieting serves as an immediate and effective bypass to these difficult emotions so that we don’t have feel our existential pain. If we focus on pounds lost or miles logged in the fit bit, we gain an immediate sense of control and mastery over of life. We have tangible ‘results’ that ‘it’s’ working and that ‘everything will be okay once we hit x on the scale or x on the tracker…

Everyone on the planet is suffering to one degree or another with something. The things that matter most to us are matters of our hearts. It can be scary or difficult to express these heart matters as they are often out of our direct awareness. We might not be able to articulate what it is we are really hungry for, but we know something below the surface is creating tension and longing. This ambiguous territory might feel scary or even threatening. It is only natural that we seek to find a sense of ground, a sense of knowing and sense of certainty. So, we turn to more tangible and measurable domains so we can track and control our lives. This is how we find certainty in an otherwise uncertain world. It makes total sense that we turn to “bio hacking” + “dieting/IF” to feel more ‘productive’ and more in ‘control’ as we chase the elusive yet -oh – so- tantalizing promises of the fountain of youth!

But I want to be healthy!

I appreciate wanting to make changes that could improve one’s health, I get it! After all, I am a dietitian/nutritionist; I care deeply and value my health too! The issue is that our culture is too obsessed with achieving health at any and all costs. We have an unhealthy obsession with health. It’s no accident that the prevalence of eating disorders continues to rise in parallel with the increase in dieting/IF, bio hacking and wellness/food obsessions! Is it really all that healthy to ignore our hungers in hopes of increasing ‘health’ and if so, at what cost? All too often we ignore mental health in the name of weight loss/changing our bodies in hopes of living a better life. How much are our lives really enhanced? And, is it really worth it? Personally, I’d rather enjoy the pleasures of eating than the elusive hope of maybe prolonging my life a few extra years.

Is our obsession with health actually making us healthier?

If you find yourself flirting with the idea of trying IF or some other trendy diet, I would invite you instead to look inward before trying to solve the problem with an outside solution. Take inventory of your life.

  • Is something in your life stressing you out or upsetting you? What keeps you up at night?
  • Are you going through a change or transition? New job, new lover?
  • Did you recently suffer a loss in your life: a partner, a pet etc.?

There is usually something else happening in our lives that is the driving force behind wanting to control food and our bodies. Get curious about your life in a deeper and more profound way. And if you want to be “healthier,” and “feel better,” then shift the focus onto behaviors instead of trying to shrink the size of your body. Health behaviors such as increasing your physical activity, getting more and better sleep, eating more vegetables, starting a meditation practice and so on.  

Intuitive Eating isn’t as sexy or glamorous as Intermittent Fasting.

If you want to honor the rhythms and wisdom of your unique body, then intuitive eating is a great place to start AND end. Intuitive eating involves listening to your hunger cues/fullness cues, and tuning into your body’s needs. You become the expert on your own body and your own health by virtue of learning the skill of interoceptive awareness. Interoceptive awareness is the ability to perceive physical as well as emotional sensations from within the body.

I’ll admit my major bias in writing this article as a practicing anti-diet dietitian, I do have an agenda to promote intuitive eating. But here’s the deal, we just don’t have enough evidence to recommend IF for long-term health, weight loss, and longevity. And, the negative effects are far more harmful than any short-term health gain. We do however have research that supports numerous positive long-term health outcomes of intuitive eating!

Feel free to contact me for any and all research articles; I will happily provide.

In good health and happiness,