What is Intermittent Fasting? … and Why It Works!


Obesity is on the rise, and marketing is always on its heels with the next fad that can be sold to desperate consumers. A new way to lose weight and look great will be marketable and profitable as long as we are looking for a quick fix.

For those of us in pursuit of long-term changes and whole-body health, however, we know that there is more to a healthy eating plan than a fad diet, more to health than the scale, and more to food than calories.

More and more, researchers are finding that when we eat may be just as important as what we eat. We unpacked this a bit when discussing what to eat when training, but the benefits of intermittent fasting extend beyond body building and athletic goals.

Intermittent Fasting on the Health Radar

Breakfast has long been touted as the most important meal of the day, which is still quite true. The meal that breaks the fast after sleeping replenishes nutrient stores, starts your digestive system up for the rest of the meals, and generally refuels your body.

We don’t often consider overnight to be a fast, though. For the skeptics reading – rest assured that you already fast every day, in a manner of speaking. Fasting isn’t always forty days and forty nights or a grand spiritual encounter – though our biggest associations and inspirations related to fasting are.

Those who observe Ramadan fasting, an annual religious festival where daily fasts are observed over the course of a month, have been the subjects of much research. In 2007, for example, a group of volunteers who were fasting during Ramadan were matched with non-fasting individuals based on similar body structure and health. At the end of the month, the Ramadan participants had significantly lower inflammation markers. (1)

With inflammation playing such a key role in many of our chronic illnesses, fasting of this sort has gained attention in the Western world, with more implications and recommendations surfacing as researchers learn more.

How Intermittent Fasting Affects the Body

The saying eat to live, don’t live to eat may help us to understand the concept of intermittent fasting a bit more. We certainly do need to eat – the body can’t go on long without nutrients to fuel its many intricate processes. But perhaps we don’t need to be so consumed with what we consume every waking moment.

The concept explored with intermittent fasting is similar to that of Paleolithic, or low/selective carbohydrate diets. Just as our ancestors had very different carbohydrates in their diets, there were also periods of time with very little caloric intake. Our bodies have obviously changed over the millennia, but perhaps the need for a resting period still exists and can be met with shorter, more controlled times of fasting.

As scientists explore this possibility, they have continuously uncovered more information about the potential benefits of intermittent fasting for the whole body, including:

  • The immune system
  • Neurological responses
  • Muscular development and metabolism

At the very least, we have an understanding of what the evening fast accomplishes. Some people even like to test their urine for ketosis – the state when your body has an exceptionally high fat-burning rate – to see the body’s release of fats in action. This is huge when it comes to metabolism and disease prevention — but there may be much more to intermittent fasting than we first realized.

Improved immune and inflammatory responses

The immune system is a complicated one, always walking the line between incredible benefits to the body and incredible damage. It is what keeps us from succumbing to the onslaught of pathogens around and on us daily, but it can also turn on us at any moment and attack itself or harmless substances.

Inflammation, in theory, is a gathering of white blood cells and other immune responses to attack and eliminate threats to the body. In practice, however, inflammation often accumulates in excess or in unnecessary places, all too often elevating to the status of inflammatory disease.

Building on growing observations of lessened inflammation during Ramadan, in 2012, a group of researchers from Saudi Arabia studied fifty people who observe Ramadan to analyze the way their bodies responded to the prolonged fast. Much like the 2007 study and others, the results indicated less inflammation during the fasting month. (2)

This particular study also noted that “systolic and diastolic blood pressures; body weight; and body fat percentage were significantly lower,” and that the decreases were only present while the participants were fasting intermittently. Once it ceased, the markers were higher again.

In laboratory studies, we also have indications that the slowed immune system extends to the allergic response. Mouse models indicate that fasting is associated with less hypersensitivity and allergic over-reactions of the immune system. (3)

Mitigated chronic illnesses

As mentioned above, inflammation is a key player in inflammatory disease, one of the most common and deadly categories of illness today. Heart disease, the top killer for men and women, and obesity are inflammatory diseases, and painful arthritic conditions are also connected to inflammation.

If intermittent fasting decreases unnecessary inflammation, it follows that disease risks decrease, as well. This theory has played out well in research, with good indications that intermittent fasting can improve long term health. Multiple fasting models have been tested for their effects on disease, with unifying results.

A German review in 2013 analyzed studies and instances where individuals followed a guided fasting regimen that restricted the amounts and times for eating – much like Ramadan – over periods of 7-21 days.  The researchers concluded that fasting is associated with deceleration or prevention of most chronic degenerative and chronic inflammatory diseases” and that we have great cause for further, more detailed studies. (4)

Another review more specifically looked at alternate-day-fasting, where certain days follow a fasting pattern while others maintain normal eating patterns. Extended to both human and animal trials to gather the most information available, they found the evidence to indicate this type of fasting ”may effectively modulate several risk factors, thereby preventing chronic diseaseand, again, warrants further research. (5)

Better brain function

We’ve heard of a good breakfast as “brain food,” but it’s possible that the brain needs a bit longer before the fast is broken. Two studies of note, both recent and both on animal models, give us indication that brain health can be improved with intermittent fasting.

One of the studies was published in 2013 and analyzed the way that both obese mice and mice with intermittent-fasting diets responded to both exercise and cognitive tests. The obese mice performed reasonably in terms of cognitive and learning ability, but they were sluggish and struggled with exercise compared with the control group. The mice fed diets with intermittent fasting were both more active and had better learning and memory capabilities than the control group. (6)

The other came a year later and honed in on memory function, in particular. After testing and observing rats for changes made from intermittent fasting, intermittent fasting was found to induce adaptive responses in the brain and periphery that can suppress inflammation and preserve cognitive function,” once again circling back to the far-reaching impact that inflammation can have on the body. (7)

When human trials are not yet available, these kinds of observations give us a good look at the potential that exists so that information can be gleaned and future studies can be developed. With inflammation as a focal point, intermittent fasting seems to be quite promising as a plan of attack for many conditions of the body and mind.

Maximized fitness training

There are various ways intermittent fasting can benefit someone who is training, but that is and was another article in itself. Today, we’re going to look at the implications of muscle development, hormone production, and how fasting is connected underneath it all.

While neurotransmitters connect our senses, brain, and body together for immediate responses, hormones connect messages gathered throughout the body with sustained, long-term directives. Once those directives have been completed, production of that hormone slows.

Growth Hormone levels tend to slow when we are no longer growing as adolescents, which is a problem for middle-aged adults who are rediscovering healthy lifestyles and working to train, bulk, or simply tone here and there.

Recalling the primal theory behind intermittent fasting, if you were running out of food and nearing hunting season once more, you would need strong muscles and a lean body to achieve your goal. Perhaps this is why growth hormone increases in times of intermittent fasting, as evidenced in early studies on the subject. (8)

The improved growth response was also noted in a 2011 study, when hormones and inflammatory responses came together to improve wound healing in mice fed with intermittent fasting diet patterns. (9)

Facilitated weight loss

With reduced inflammation markers – a prominent risk factor for obesity – and improved growth hormone for muscle development, weight loss is next in the logical progression of benefits of intermittent fasting.

Over the course of ten weeks, University of Illinois researchers monitored adults following a control diet, then alternate-day intermittent fasting patterns. Not only was weight loss significant, but cholesterol, triglycerides, and blood pressure decreased, as well. (10)

Enough studies on intermittent fasting and weight loss have been executed that a 2015 review analyzed whether this was simply another fad diet or if it carries any validity. They acknowledged – as we all should – that there is no magic bullet or one-size solution for obesity and weight loss. However, given the documented effects and results of intermittent fasting, it should be considered a viable option for individuals and care providers to consider. (11)

As with any adjustment to diet or exercise, care should be taken to ensure it’s right for the individual. Women in child bearing years, especially, must exercise caution.

While intermittent fasting hasn’t necessarily shown problems for unborn babies or the maternal phase of life, increased cortisol levels have been noted, which can cause problems all their own. (12) If any diet plan is causing you stress, anxiety, or mental difficulty, it is likely doing more harm than good and an alternative should be sought.

Types of Intermittent Fasting

There are many ways an intermittent fasting plan can play out. The most extreme versions include full days without eating anything at all, usually once every week or less. While some people like to work up to 24-hour fasts, it is not likely the path to take when you are just setting out. Jumping into a full day’s fast without preparation can leave you feeling weak and hungry rather than rested and rejuvenated.

Consider first building on your natural fast – night times without eating – slowly and deliberately, to reinforce its function as an extended rest period.

Nutrients are important, but remember that the entire body works to process every bite, all the way through to the liver sorting toxins and the blood circulating nutrients that have been gleaned. You can use a break!

Ensuring a full 12 hours between dinner and breakfast, with no snacking after or early eating after a short night’s sleep, gives your body half the day to recharge before being confronted with food again.

To extend the resting period, consider delaying or “skipping” breakfast, pushing the first meal of the day out a few hours, making the time between breakfast and dinner closer to 2/3rds of the day instead of only half. This can be executed daily or only a few times each week, depending on what your body needs and the way it responds.

Feelings of hunger may come in habitual waves. It’s important to respond to these properly. They shouldn’t be ignored, but neither do you need to jump to a full meal and break the fast immediately. Smoothies are often used as a semi “digested” food to ease the pangs and still be easy on the body. (Do note that the consumption of smoothies, if containing protein or even low glycemic carbohydrates, will interrupt the body’s state of ketosis by converting to sugar, but may have less of an impact on digestion, inflammation, and brain function.) Other coping mechanisms that are thought to have less of an effect on ketosis are black or bulletproof coffee, extremely low-glycemic greens, or coconut oil and other fats without sugar.

In any case, I do believe in listening to the body, but remember that food entering the body is still food that must be attended to by the body’s systems. Drinking the water you normally would – to total at least half of your body weight in ounces for the day – or herbal tea provides hydration and a sense of fullness without much to process or digest.

Do avoid sugar – particularly in the form of the ever-popular juice fast (if focussing on fruits), as this actually amounts to little other than sugar. Remember that ketosis is the breaking down of fat instead of carbohydrates for energy, so supplying it with sugar interrupts this process. Any kind of food ends the break that the fast intends to provide to the body.

As you adapt to these intermittent fasting patterns, more stringent plans can be considered. Taking cues from nomads and warriors who would travel on foot during the day and rest at night, or the full-day fasts in many religions, meals may be consumed within windows of as much as 6 hours of the day to as little as 3 hours of the day.

It’s important to note that most of the studies on intermittent fasting did not include caloric restriction. In other words, your body still needs plenty of varied, nutrient dense foods, even if you are eating them during a shorter period of the day. If you’re eating one or two meals in your fasting window, make sure to get the full day’s calories and nutrients packed in!

Have you tried intermittent fasting? I would love to know your experience in the comments below!

UPDATE: My newest article An Intermittent Fasting Guide for Men & Women addresses the difference in risk of intermittent fasting for women and men.


Dr. B.J. Hardick

About Dr. B.J. Hardick

Dr. B.J. Hardick is a Doctor of Chiropractic and internationally-recognized natural health author and speaker. His health journey began as a child — alternative medicine is the only medicine he has ever known. In 2009, he authored his first book, Maximized Living Nutrition Plans. In 2018, he authored his second book, Align Your Health. An energizing and passionate speaker, Dr. Hardick shares his lifestyle methods to numerous professional and public audiences every year in the United States and Canada. His teachings encompass the principles of ancestral nutrition, detoxification, functional fitness, mindfulness, and green living. Learn More