10 Evidence-Based Health Benefits of Intermittent Fasting

10 Evidence-Based Health Benefits of Intermittent Fasting

At some point you've probably seen the words "Intermittent Fasting", heard one of your friends talk about it, but for most of us, we've never really been told what it ACTUALLY is or WHY you should potentially give it a go. Below are reasons/benefits that may sway you to do so.

Written by Kris Gunnars, BScon August 16, 2016

Intermittent fasting is an eating pattern where you cycle between periods of eating and fasting.

Numerous studies show that it can have powerful benefits for your body and brain.

Here are 10 evidence-based health benefits of intermittent fasting.

1. Intermittent Fasting Changes The Function of Cells, Genes and Hormones

When you don't eat for a while, several things happen in your body.

For example, your body initiates important cellular repair processes and changes hormone levels to make stored body fat more accessible.

Here are some of the changes that occur in your body during fasting:

  • Insulin levels: Blood levels of insulin drop significantly, which facilitates fat burning (1).
  • Human growth hormone: The blood levels of growth hormone may increase as much as 5-fold (23). Higher levels of this hormone facilitate fat burning and muscle gain, and have numerous other benefits (45).
  • Cellular repair: The body induces important cellular repair processes, such as removing waste material from cells (6).
  • Gene expression: There are beneficial changes in several genes and molecules related to longevity and protection against disease (78).

Many of the benefits of intermittent fasting are related to these changes in hormones, gene expression and function of cells.

BOTTOM LINE:When you fast, insulin levels drop and human growth hormone increases. Your cells also initiate important cellular repair processes and change which genes they express.

2. Intermittent Fasting Can Help You Lose Weight and Belly Fat

Many of those who try intermittent fasting are doing it in order to lose weight (9).

Generally speaking, intermittent fasting will make you eat fewer meals.

Unless if you compensate by eating much more during the other meals, you will end up taking in fewer calories.

Additionally, intermittent fasting enhances hormone function to facilitate weight loss.

Lower insulin levels, higher growth hormone levels and increased amounts of norepinephrine (noradrenaline) all increase the breakdown of body fat and facilitate its use for energy.

For this reason, short-term fasting actually increases your metabolic rate by 3.6-14%, helping you burn even more calories (1011).

In other words, intermittent fasting works on both sides of the calorie equation. It boosts your metabolic rate (increases calories out) and reduces the amount of food you eat (reduces calories in).

According to a 2014 review of the scientific literature, intermittent fasting can cause weight loss of 3-8% over 3-24 weeks (12). This is a huge amount.

The people also lost 4-7% of their waist circumference, which indicates that they lost lots of belly fat, the harmful fat in the abdominal cavity that causes disease.

One review study also showed that intermittent fasting caused less muscle loss than continuous calorie restriction (13).

All things considered, intermittent fasting can be an incredibly powerful weight loss tool. More details here: How Intermittent Fasting Can Help You Lose Weight.

BOTTOM LINE:Intermittent fasting helps you eat fewer calories, while boosting metabolism slightly. It is a very effective tool to lose weight and belly fat.

3. Intermittent Fasting Can Reduce Insulin Resistance, Lowering Your Risk of Type 2 Diabetes

Type 2 diabetes has become incredibly common in recent decades.

Its main feature is high blood sugar levels in the context of insulin resistance.

Anything that reduces insulin resistance should help lower blood sugar levels and protect against type 2 diabetes.

Interestingly, intermittent fasting has been shown to have major benefits for insulin resistance and lead to an impressive reduction in blood sugar levels (12).

In human studies on intermittent fasting, fasting blood sugar has been reduced by 3-6%, while fasting insulin has been reduced by 20-31% (12).

One study in diabetic rats also showed that intermittent fasting protected against kidney damage, one of the most severe complications of diabetes (13).

What this implies, is that intermittent fasting may be highly protective for people who are at risk of developing type 2 diabetes.

However, there may be some differences between genders. One study in womenshowed that blood sugar control actually worsened after a 22-day long intermittent fasting protocol (14).

BOTTOM LINE:Intermittent fasting can reduce insulin resistance and lower blood sugar levels, at least in men.

4. Intermittent Fasting Can Reduce Oxidative Stress and Inflammation in The Body

Oxidative stress is one of the steps towards aging and many chronic diseases (14).

It involves unstable molecules called free radicals, which react with other important molecules (like protein and DNA) and damage them (15).

Several studies show that intermittent fasting may enhance the body's resistance to oxidative stress (1617).

Additionally, studies show that intermittent fasting can help fight inflammation, another key driver of all sorts of common diseases (171819).

BOTTOM LINE:Studies show that intermittent fasting can reduce oxidative damage and inflammation in the body. This should have benefits against aging and development of numerous diseases.

5. Intermittent Fasting May be Beneficial For Heart Health

Heart disease is currently the world's biggest killer (20).

It is known that various health markers (so-called "risk factors") are associated with either an increased or decreased risk of heart disease.

Intermittent fasting has been shown to improve numerous different risk factors, including blood pressure, total and LDL cholesterol, blood triglycerides, inflammatory markers and blood sugar levels (12212223).

However, a lot of this is based on animal studies. The effects on heart health need to be studied a lot further in humans before recommendations can be made.

BOTTOM LINE:Studies show that intermittent fasting can improve numerous risk factors for heart disease such as blood pressure, cholesterol levels, triglycerides and inflammatory markers.

6. Intermittent Fasting Induces Various Cellular Repair Processes

When we fast, the cells in the body initiate a cellular "waste removal" process called autophagy (724).

This involves the cells breaking down and metabolizing broken and dysfunctional proteins that build up inside cells over time.

Increased autophagy may provide protection against several diseases, including cancer and Alzheimer's disease (2526).

BOTTOM LINE:Fasting triggers a metabolic pathway called autophagy, which removes waste material from cells.

7. Intermittent Fasting May Help Prevent Cancer

Cancer is a terrible disease, characterized by uncontrolled growth of cells.

Fasting has been shown to have several beneficial effects on metabolism that may lead to reduced risk of cancer.

Although human studies are needed, promising evidence from animal studies indicates that intermittent fasting may help prevent cancer (27282930).

There is also some evidence on human cancer patients, showing that fasting reduced various side effects of chemotherapy (31).

BOTTOM LINE:Intermittent fasting has been shown to help prevent cancer in animal studies. One paper in humans showed that it can reduce side effects caused by chemotherapy.

8. Intermittent Fasting is Good For Your Brain

What is good for the body is often good for the brain as well.

Intermittent fasting improves various metabolic features known to be important forbrain health.

This includes reduced oxidative stress, reduced inflammation and a reduction in blood sugar levels and insulin resistance.

Several studies in rats have shown that intermittent fasting may increase the growth of new nerve cells, which should have benefits for brain function (3233).

It also increases levels of a brain hormone called brain-derived neurotrophic factor (BDNF) (323435), a deficiency of which has been implicated in depression and various other brain problems (36).

Animal studies have also shown that intermittent fasting protects against brain damage due to strokes (37).

BOTTOM LINE:Intermittent fasting may have important benefits for brain health. It may increase growth of new neurons and protect the brain from damage.

9. Intermittent Fasting May Help Prevent Alzheimer's Disease

Alzheimer's disease is the world's most common neurodegenerative disease.

There is no cure available for Alzheimer's, so preventing it from showing up in the first place is critical.

A study in rats shows that intermittent fasting may delay the onset of Alzheimer's disease or reduce its severity (38).

In a series of case reports, a lifestyle intervention that included daily short-term fasts was able to significantly improve Alzheimer's symptoms in 9 out of 10 patients (39).

Animal studies also suggest that fasting may protect against other neurodegenerative diseases, including Parkinson's and Huntington's disease (4041).

However, more research in humans is needed.

BOTTOM LINE:Studies in animals suggest that intermittent fasting may be protective against neurodegenerative diseases like Alzheimer's disease.

10. Intermittent Fasting May Extend Your Lifespan, Helping You Live Longer

One of the most exciting applications of intermittent fasting may be its ability to extend lifespan.

Studies in rats have shown that intermittent fasting extends lifespan in a similar way as continuous calorie restriction (4243).

In some of these studies, the effects were quite dramatic. In one of them, rats that fasted every other day lived 83% longer than rats who weren't fasted (44).

Although this is far from being proven in humans, intermittent fasting has become very popular among the anti-aging crowd.

Given the known benefits for metabolism and all sorts of health markers, it makes sense that intermittent fasting could help you live a longer and healthier life.

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Are you simply "going through the motions" or are you helping your brain actually connect with the muscle and the movement pattern you are trying to complete. Take a read through this StrongFirst article for an understanding of how low intensity lifts/movements can greatly improve your workout returns

By Craig Marker
Ph.D., Team Leader

The term “grease the groove” (or GTG) is used frequently at StrongFirst. The basic premise in greasing the groove is to repeat the same exercise frequently without going to muscular fatigue. In this article, we are going to take a deeper dive into the origins of the term, what happens in the brain and at the neuromuscular junction, and principles of this type of programming.

Specificity + frequent practice = success. It is so obvious, most people don’t get it. Once I came across a question posted on a popular powerlifting website by a young Marine: how should he train to be able to do more chin-ups? I was amused when I read the arcane and non-specific advice the trooper had received: straight-arm pull-downs, reverse curls, avoiding the negative part of the chin-up every third workout… I had a radical thought: if you want to get good at chin-ups, why not try to do… a lot of chin-ups? —Pavel Tsatsouline, 1999

Greasing the groove (GTG) is a type of programming that builds the neurological pathway of lifting heavy weight. It does not rely on breaking down down muscle tissue for more growth, rather it uses your existing muscle structure by building new neural pathways. That is, it builds better wiring. Pavel, in his book Power to the People, described GTG with the following:

Muscle failure is more than unnecessary—it is counterproductive! Neuroscientists have known for half a century that if you stimulate a neural pathway, say the bench press groove, and the outcome is positive, future benching will be easier, thanks to the so-called Hebbian rule. The groove has been ‘greased’. Next time the same amount of mental effort will result in a heavier bench. This is training to success! The opposite is also true. If your body fails to perform your brain’s command, the groove will get ‘rusty’. You are pushing as hard as usual, but the muscles contract weaker than before! To paraphrase powerlifting champ Dr. Terry Todd, if you are training to failure, you are training to fail.

The Mechanism Behind GTG

There are a few different mechanisms behind GTG. The first happens at the muscle and the second is neurological. At the neuromuscular junction, our neurons signal the muscle fibers to fire. Not all muscle fibers are used and we can squeeze out more strength if we learn how to recruit more fibers. To do this, we need more frequent firing from the neurons. We can train our neurons to fire more frequently by doing the movement more frequently.

The other component of this idea is that we use different muscles in our movements. In a press, our lat, tricep, stabilizers, and shoulder muscles all have to fire in a choreographed pattern to press the weight overhead. We need to coordinate these muscles to fire in a perfect symphony. Donald Hebb theorized that neurons wire together if they fire together. Thus, the more we do the movement the more we build the pattern of firing between muscles. If you perform the same movement perfectly and frequently, we build better wiring.

The other mechanism for greasing the groove is what happens in our brain. We have a primary motor cortex that initiates the signal down the spinal cord for the muscle to trigger. Other areas of our brain coordinate the movement before the signal is even sent down the spinal cord. If we can ‘practice’ the movement with our brain, we will get better at it. If we put people in an fMRI scanner and ask them to imagine doing an exercise, we see activation in the premotor cortex. The premotor cortex is where we visualize the movement before actually performing it. Years ago, Dr. Judd Biasiotto showed this relationship with basketball players. He had basketball players visualize a free throw multiple times before shooting. The mental practice improved their free throw shooting by 24 percent.

Dr. Biasiotto talks in the below excerpt about how he completed thousands of mental repetitions squats. Without lifting a single weight, he choreographed how each muscle moved prior to the squat.

Every one of the lifts I made during those initial training sessions was videotaped from three different angles. After each lift, the tapes were played back so Dr. Spieth and I could analyze my mistakes. Then, I would “mentally correct” each mistake. …Once he filmed me making the lifts with perfect form, we got Faye Reid, a Disney cartoonist, to replicate each frame of the film. … After they were completed, they were made into a loop so I could view them continuously with a loop-film projector. By viewing the film, I became aware of the muscles I was using during each segment of my lifts…I knew exactly which muscles to recruit and concentrate on to make the lift. The films also helped me to perfect my form. For example, it taught me the exact moment during my squat when I should kick my hips in and throw my shoulders back. In short, by using the films as a training aid, I learned to synchronize my mind with my body. … During the next two years of training, I must have reviewed those films at least 10,000 times.


The Principles of GTG

  1. Train frequently
  2. Train with moderate to light weights
  3. Train with medium to high volume


Greasing the groove has been used by many at StrongFirst. It fits with our principles of never going to failure and practicing in a perfect manner. By doing the movements once in a while in small bursts, we can devote the mental energy it takes to building perfect practice. It also teaches how tension builds strength. It is not the size of the muscle that matters as much as how well we utilize it. Greasing the groove develops the neural patterns needed for maximum strength.


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If you ever wonder why we are constantly saying "tighten up" or "squeeze your glutes" or "get organized". This article will do a good job of explaining how paramount the concept of tension is when it comes to safely performing human movement and developing strength.

By Craig Marker
Ph.D., Team Leader

“Your muscles are already capable of lifting a car, they just don’t know it yet.”—Pavel Tsatsouline

Your muscular system is a lot stronger than you might realize. You are already capable of lifting incredibly heavy objects. However, your body has limiting factors built in, so you don’t accidentally do things like tear your tendons from your bones.

These limitations are good, but also tend to be overprotective.There are a few skills of strength we can use that help us (safely) reduce these limitations—and therefore increase our performance.

Get Tight

If you pay attention to StrongFirst content or attend an event, you might notice a consistent message of “get tight.” Why is that referenced so often? Why is tightness important to pushing a heavy kettlebell overhead, pulling a heavy object off the ground, or doing a one-handed push-up?

The first reason might seem obvious. When we press or pull an object from the ground, the force of the press needs to get transferred into the ground. If we are loose like a noodle, our press must overcome the wobble. If we are tight, the force gets directly transferred into the ground. If we were building a multi-story building, we would not start the first floor with thin wood as it would have too much flexion. Rather, we start it with concrete or steel beams.

The second purpose of tension is to inhibit safety signals that protect our muscle and tendons from hurting themselves. These safety mechanisms protect us from danger (seehere and here for great videos that illustrate these mechanisms), and these systems respond quickly and automatically. One example is when you go to the doctor and he or she taps your knee. When a medical professional taps on a ligament in your knee, your knee quickly responds with a kick (called the stretch reflex). The signal does not go to your brain and then you consciously decide to kick. Rather, a signal from the tendon stretching went into your spinal cord and the muscle contracted.


Another safety mechanism, the inverse stretch reflex, leads our muscles to relax when the tendon is pulled too much. If we were able to inhibit this safety signal, we could create a stronger muscular contraction. Tension inhibits the circuitry that tells the muscle to relax.

Charles Sherrington, a famous physiologist, created a model for neuromuscular facilitation and inhibition. Sherrington’s Law of Irradiation describes when muscles recruit nearby muscles.1 Pavel called this law “muscle cheering,” as nearby tight muscles cheer the working muscles to work harder.2

Here is how Pavel described it:

“Make a tight fist. Where do you feel the tension? Your forearm and biceps, right? Even tighter! White knuckles! Do you feel your shoulder and even chest flexing too? In reality, when the demand for force increases, other muscles jump in on the action. Like a stone dropped in the water sends ripples across the surface, tension spreads—irradiates—from the muscle directly responsible for the job at hand towards others. The bigger the stone, the taller are the waves and the further they spread! … It states that a muscle working hard recruits the neighborhood muscles, and if they are already a part of the action, it amplifies their strength! Not by cheating, as some complement their barbell curls with a back swing, but by ‘cheering’. The neural impulses emitted by the contracting muscle reach other muscles and ‘turn them on’ as electric current starts a motor.”

For the full article...click on the Title above.


Sometimes Less is More.....


Sometimes Less is More.....

This is a great article brought to us by StrongFirst. It's great because it speaks to an issue or an ideal that is ever present in today's fitness industry. That the most important thing is GOING HARD, INTENSE, CRAZY EVERY SINGLE WORKOUT! The problem with this statement is that although high intensity training certainly has its place in our training program as well as many others, it can't be all the time, every time. For a better understanding of WHY, take a read below.



By Matt Kingstone


In the current culture of the fitness world, it seems that taking extended rest periods or working at an intensity level that is less than maximum is considered a waste of time. However, there are many in the fitness industry who are making a case for a more measured approach to strength and conditioning training. None more so than Pavel Tsatsouline.

Pavel’s latest set of principle based training protocols, called Strong Endurance™, paints a picture of a world in which we can train at a level that may seem blasphemous to some and too good to be true to others. But, by following the principles laid out by Strong Endurance™, improvements in endurance or conditioning can be seen more quickly and much more safely than with many of today’s popular methods. Let’s explore why.

The Problems with Glycolytic Training

Many of today’s popular training approaches use metabolic conditioning (metcons), the most well known example being high intensity interval training (HIIT), which uses primarily the glycolytic energy system (more on this system below). These are intervals that have a high energy output for short to medium work sets followed by a short rest before repeating the set. These are the sessions that make you want to throw up, make your muscles feel like they are going to burst into flames, and make it difficult to climb the stairs to change out of your training clothes.

The issue with primarily using the glycolytic system for extended periods of time—both over the duration of a training session, and especially day in and day out—is all the metabolic waste this system produces. This waste can present itself as that burning in the muscles that has become so coveted, but in fact can be quite detrimental to our progress and health, as we will see in a minute.

That isn’t to say that this style of training doesn’t have its place, but it lies mostly in the realm of your peaking cycle. The take-home message here is that physical training that exploits this high waste energy system doesn’t create a favorable internal environment to see the best results.

So, what is the alternative? Enter “anti-glycolytic training.”

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