Intermittent fasting

Intermittent fasting is a fast growing way of eating…or more like, of not eating :D…

There are really tons of benefits to fasting. This study shows that the body can completely regenerate the immune system in only 3 days of fasting.
Some athletes tend to be scared of fasting because of the myth of metabolic slow down, or because of the fear that they can’t build muscle or that they’ll go catabolic or crazy stuff like that.
The truth is, your metabolism actually speeds up when fasting. 48 hours of fasting increases your metabolic rate by 3.6%.
So let me explain why…


Increases Fat Loss

When you’re in a fasted state, insulin is very low. The body then releases catecholamines (adrenaline & noradrenaline). These two hormones increase mental focus, blood flow to the muscles and induce fat loss (stubborn body fat).
Fat cells are controlled by two receptors – Alpha 2 receptors and beta 2 receptors.
Alpha 2 receptors inhibit fat to leave the adipose tissue, and beta 2 receptors allow fat to leave the adipose tissue. Being in a low insulin state inhibits the alpha 2 receptors and activates beta 2 receptors.
Now that the cell is ‘open’ to fat loss, catecholamines activate hormone sensitive lipase (HSL), which then shuttles the fat out of the adipose tissue.
Second advantage of being in a fasted state is that it increases abdominal subcutaneous blood flow. Which happens to be the area where all that stubborn fat lies.
Third advantage is that fasting increases adiponectin. The more fat you have, the less adiponectin you have and vice versa. Adiponectin improves insulin sensitivity and as well as fat oxidation. More fat oxidation = greater fat loss.
Fasting enhances fat loss in three incredible ways.
Not only does intermittent fasting speed up fat loss, but it also aids in recovery, helps to build muscle and to retain lean mass. How? By increasing HGH.


Increases HGH

Fasting is well known for its ability to boost HGH.
This study was done on a guy who fasted for 40 days, for religious reasons. After 26 days his HGH had increased by 1250% and he had a 300% increase after the first 5 days.
Here it is shown that HGH increases by 500% after just 2 days of fasting.
This study even claims a 2,000% increase in HGH after 24 hours.
So what does HGH (human growth hormone) do?…


  • induces fat burning
  • spares lean mass when your body is in a caloric deficit
  • helps build / regenerate bones, joints and muscles
  • speeds up recovery after a workout and much more.
The elevated levels of catecholamines from fasting will also allow you to perform more intense in your workouts and will aid in recovering faster.
Fasting doesn’t only increase the levels of HGH, but also its secretion frequency.
However, HGH isn’t the only anabolic hormone that is elevated during fasting. Another one is testosterone.



Intermittent fasting impacts your testosterone. You can look at it in a positive or a negative way.
Reason 1:
When you eat, leptin rises, making your stomach feel full. Leptin stimulates testosterone production by stimulating LH secretion, and during a fast, leptin is low.
Reason 2:
In this study it shows that an overnight fast (approx 12 hours or so) increased luteinizing hormone (LH) by 67% and testosterone response thereof by 180% in non-obese men.
Testosterone increases when you sleep, it’s highest in the morning and lowest in the evening, so during night hours, or more like sleeping hours, testosterone elevates again to peak in the morning.

Reason 3:

Overall, fasting decreases testosterone (1, 2).
But, all is not lost. Testosterone production is more sensitive to stimulating hormones such as LH and insulin (fasting increase increase insulin sensitivity).
Also when you eat after a fast, LH overshoots above baseline. So a greater increase in LH, plus a 180% greater testosterone sensitivity to it will lead to a greater increase in testosterone production.
So combine that awesome testosterone surge with a fasted weight training session to boost testosterone even higher.


Induces Autophagy

Fasting helps to detox the body. And with less toxins in the body, the body’s organs can now function normally.
And a few benefits of a detoxed body are:
  • Better IFG-1 conversion by the liver
  • Healthy control of inflammation
  • Better production of testosterone
  • Increase sensitivity to receptors, such as androgen and dopamine receptors
  • Cleaner cells, leading to longevity
  • Better concentration
  • More effective flushing of estrogen out of the body
Short term fasting leads to a dramatic upregulation in neuronal autophagy which has a neuroprotective effect. Your neurons are very important for signalling, including protein sythesis, testosterone production and everything important in your brain.
Plus, muscle autophagy is extremely important. Autophagy is the process of the body getting rid of dead/destroyed cells. Inhibiting autophagy will worsen muscle loss during fasting. Thus, autophagy flux is important to preserve muscle mass and to maintain myofiber integrity (3).


Lowers Cortisol

As seen in this study, eating only once a day lowers cortisol quite significantly. This could be because the fasting group’s cortisol was tested in the afternoon (when cortisol is lowest) and the non fasting group’s cortisol was tested in the morning (when cortisol is highest).
Adapting to intermittent fasting will blunt cortisol response as your body will ‘know’ that it’s not in starvation, but it will ‘expect’ food later the day.
As we know, cortisol directly lowers testosterone. So low cortisol will only help your testosterone to stay elevated throughout the fast. (4)
Cortisol not only lowers your testosterone, but also causes muscle breakdown and visceral fat gain, and it also slows down the immune system. (5, 6)
Shorter fasting times (14-16 hours) also have the ability to make the body more resilient to stress. Hence, by constantly putting it under stress with fasting, the body becomes resilient, by lowering oxidative stress. (7)
Related: If you are afraid of muscle catabolism, read this article about whether fasting will make you catabolic or not…


Improves Insulin Sensitivity

Fasting improves insulin sensitivity. (8) Being insulin resistant inhibits the body to utilize glucose and other nutrients, and therefore increases blood sugar. It makes a person constantly feel tired, having little concentration and difficulty doing everyday activities.
Being insulin sensitive helps the body to recover faster, provides the body with lots of energy, helps to stabilize your blood sugar, helps to transport nutrients and amino acids into the muscles etc.
Fasting releases adiponectin, which is one of the big factors that improves insulin sensitivity. (9)
One thing to keep in mind, is that the longer the fast continues, the more free fatty acids are released from adipose tissue and the more insulin resistant you can become. A longer than 24 hour fast could lead to an increases in intramyocellular and hepatic triglycerides. Meaning, fat will start to store in your muscles and liver and this will increase insulin resistance and could effect glycogen storage capacity, by lowering it, and disrupt normal cellular function. (10) So, try to keep your fasts below 24 hours.



Reduces Inflammation & improving brain function

Intermittent fasting reduces inflammation markers (10, 11).
The ramadan fasting (only about 12 hours of fasting) shows to significantly lower pro-inflammatory cytokines IL-1β, IL-6, and tumor necrosis factor α, and longer fasts (16+) also have the same effect (12). The reduction in inflammation will directly have a beneficial effect on cognitive function during times of stress. (13)
One possible factor is the increase in adiponectin. Adiponectin is also anti-inflammatory.

A few other benefits:

  • Lowers blood sugar
  • Lowers cholesterol pressure
  • Lower cholesterol
  • Reduces oxidative stress



Doing heavy lifting while being in a fasted state increases the release of HGH even more and also skyrockets the release of catecholamines. (13, 14)
However make sure to take some BCAAs before fasting as this will help to prevent muscle catabolism.
Related: Read here about fasted weight training and hypertrophy



There are many other health benefits to fasting other than just these mentioned above. There are many other varieties of ways to do intermittent fasting, so you can experiment to see which one works best for you. Experiment with some and see which fits you best. Remember, hunger will not disappear suddenly, your body first needs to adapt to your new eating regiment.

15 thoughts on “Intermittent fasting

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