Intermittent fasting

Intermittent Fasting – Too Fast or Not Fast Enough… Is That Your Question?

To Fast or Not to Fast… Is That Your Question?

When it comes to some of the more popular health trends that have gone mainstream today, fasting is high on the list. Not only has it been shown to offer significant health benefits when 1studied, there is also an evolutionary predisposition to it.

For tens of thousands of years, we humans went long stretches of time without food – until the opportunity came to catch enough meat to feed the tribe or gather enough roots and berries to have a feast. Either way, the eating-every-few-hours equation our society employs today is a luxury we, at one point, did not possess. 

In today’s definition, the term ‘fasting’ really refers to two options: 

  • Intermittent fasting (IF) is the more user-friendly fasting option with a fasting period of approximately 16 hours, followed by an eight-hour period of feasting. Now, this is not to be employed literally – dining glutinously for eight hours straight on turkey legs, pastries and inordinate amounts of bread and other indulgent carbs. This simply means fasting for a period of 16 hours (including sleep) and perhaps having your meals spread throughout the hours of 12-8pm.  
  • Standard fasting refers to a period of 24 hours with no caloric intake.

Now, let’s talk about some of the physical benefits!

Intermittent fasting has been associated with several different health benefits. This includes everything from fat burning and weight loss to stabilizing blood pressure and glucose. Another selling point? When done properly, the side-effects tend to be very minimal.

From a scientific perspective, several studies have revealed that fasting can have a positive impact on blood sugar by reducing insulin resistance. And this has the potential to be especially significant for those as risk of, or currently attempting to manage, diabetes.

Why? Simply put, decreasing insulin resistance can actually increase your body’s sensitivity to insulin and this can assist in making the transport of glucose from your bloodstream into your cells much more effective and efficient. 

And for individuals struggling with hypoglycemia (those that tend towards blood sugar crashes without an actual diabetes diagnosis), this ability to increase your bodies sensitivity to insulin, combined with the potential blood-sugar regulation effects that often accompany fasting, can help minimize or even significantly reduce spikes and crashes in your daily blood sugar levels. 

Ok – let’s briefly touch on the differences between men and women. And for purposes of keeping this at a user-friendly word count, we’re keeping this to fasting only.

A glucose tolerance 3study by PubMed assessed the impact of a 3-week alternate-day fasting schedule on glucose tolerance and skeletal muscle expression of genes involved in fatty acid transportation/oxidation, mitochondrial biogenesis and stress response – meaning a female physiology versus a male physiology.

The results? Alternate-day fasting impaired blood sugar control in women but had no effect in men. The moral of the story here is always work with your healthcare provider to successfully monitor the results of any new diet-based health regiments.

Now, how about what fasting does to your metabolism and how it promotes weight loss? 

Another 4study by PubMed sought to test the impact “short-term starvation” had on “resting energy expenditure.” In other words, what impact does intermittent fasting have on your resting metabolism? And this is a topic that has been met with conflicting research for decades, according to the same study.

In this particular instance, an increase in resting energy expenditure was noticed, in addition to an increase plasma norepinephrine (a neurotransmitter known to potentially enhance weight loss). 

Additional 5studies by the same entity revealed that whole-day fasting over a 12-24-week period was effective in reducing body weight by up to 9% in test subjects, with a combined decrease in body fat as well. And finally, fasting was also found to be more effective that caloric restriction at increasing fat loss while simultaneously preserving muscle tissue. 

How about heart health? Can fasting do anything for your heart health?

Did you know that heart disease accounts for an 6estimated 31.5% of annual deaths globally – making it the leading cause of death around the world?

And while there are several contributing factors to heart disease, one of the top offenders is poor diet and the high cholesterol. 

Cholesterol is a waxy, fat-like substance that inhibits the cells all over your body. And this is a good thing. Your body actually requires a certain amount of cholesterol to make vitamin D, hormones and the digestive substances that helps you assimilate your food

But when cholesterol gets out of hand, this is when problems arise. Your body instinctually makes all the cholesterol it needs to maintain optimum functioning. This means the additional cholesterol we get from fatty foods is surplus and when consumed in mass quantities, this can be harmful to the system. 

Too much cholesterol can often result in an increased risk of heart disease, stroke, peripheral artery disease and overall poor health. We’ll call this bad cholesterol.

So what impact can fasting have on cholesterol and heart health? 

Quite a positive one, it would seem. A 7study assessed on alternate-day fasting revealed that it reduced levels of bad cholesterol by 25% and blood triglycerides (types of fat found in your blood) by 32%. Not to mention, 8another revealed an association between fasting and a lower risk of coronary artery disease, as well as a significantly lower risk of developing diabetes (also a precursor for heart disease). 

And for Inflammation???

Yes! Intermittent fasting can also target and reduce inflammation due to the positive impact it has on our digestive tract, immune system and reducing typical inflammatory markers.

  • It makes sense if you think about it: We need a recommended 8 hours of rest nightly to effectively reset and rebalance. Why should our digestive system be any different? Intermittent periods of fasting can have a positive impact on the overall composition of gut microbiota.
  • It also increases the production of a hydroxybutrate compound known to suppress part of the immune response involved in inflammatory disorders like rheumatoid arthritis, diabetes and even Alzheimer’s disease.
  • It also promotes a significant reduction in the usual suspects when it comes to inflammatory markers: cytokines and c-reactive protein (a protein produced by the liver in response to bacterial infection and inflammation).
  • A reduction in insulin resistance (as discussed above) is also a positive result of fasting and key to managing inflammation.
  • And finally, an increased efficiency in immune response throughout your cells is also an added benefit of fasting that’s extremely helpful in reducing and preventing inflammation.

Now…let’s get into a big one here. What about the brain? Can fasting have a positive impact on overall brain function?

Survey says… of course! 

There are many in the medical field that attest to the benefits of intermittent fasting on brain function. Why? One theory is that metabolic transfer between glucose and ketones keeps cognition primed and degenerative diseases at bay. It goes something like this:

9“Metabolic switching impacts multiple signaling pathways that promote neuroplasticity and resistance of the brain to injury and disease.”

Ketones are the acid that that remains when the body burns its own fat. The liver holds the responsibility of converting fatty acids into ketones, which are then released into the bloodstream for use as energy. And unlike fatty acids, ketones can cross the blood-brain barrier and provide energy for the bran in the absence of glucose (the body’s main energy source resulting from the breakdown of dietary carbohydrates).

Therefore, ketosis (another rising health trend) is a metabolic state that occurs as a result of withholding food for an extended period of time and utilizes ketones as the main source of energy for the body and the brain. And some studies assert that BHB (a major ketone) may be an even more efficient fuel for the brain and the body than glucose.

Not to mention, several animal-based studies suggest a correlation between fasting and the prevention and management of both 10Alzheimer’s and 11Parkinson’s – two of the most common neurodegenerative disorders. 

Now, while we’re on the subject of disease maintenance and prevention here, what about cancer?  Is it true that fasting has a positive impact on cancer prevention and chemotherapy.

Yes. A test-tube 12study revealed positive ramifications from exposing cancer cells to several fasting cycles. In fact, the results proved to be as effective as chemotherapy in delaying tumor growth and enhanced the effectiveness of chemo on the formation of new cancer cells.

And finally, as a result of all these previously discusses benefits, fasting can have a consequential positive effect on extending longevity.

In fact, one 13study assessing the impact of every-other-day fasting in rats found a delayed onset in aging and an 83% increase in overall longevity as compared to those rats that didn’t fast. 

Alright, let’s briefly recap…

Autophagy: Both IF and standard fasting prompt a natural systemic response called autophagy. This refers to the body’s innate ability to feed itself on stored waste products and old, damaged cells, consequently replacing them with new ones. It’s like cleaning house on a cellular level.

Heart health: Alternate-day fasting reduced levels of bad cholesterol and blood triglycerides, in addition to potentially lowering the risk of coronary artery disease and diabetes.

Inflammation: Intermittent fasting can also target and reduce inflammation due to the positive impact it has on our digestive tract, the increase in hydroxybutrate production, a decrease in CRP and an overall increase in immune efficiency at the cellular level.

Blood sugar: Decreasing insulin resistance can actually increase your body’s sensitivity to insulin and this can assist in making the transport of glucose from your bloodstream into your cells much more effective and efficient.

Brain function: Metabolic transfer between glucose and ketones keeps cognition primed and degenerative diseases at bay.

Fat loss: In a fasting state, your body will start burning through your fat stores for energy. It also makes you more sensitive to the experience of feeling full after meals, making you less likely to overeat.

Immunity: Fasting for up to 72 hours can regenerate your entire immune system by kickstarting your production of infection-fighting white blood cells.

Mental clarity: When your body depletes its glycogen stores, it switches to burning fat (ketones), which are known to be neuroprotective.

Muscle building: Fasting can also increase human growth hormone (HGH) production – one of your bodies most important hormones related to building and sustaining muscle tissue.

Longevity: And all of the above-mentioned benefits can have a significant impact on the aging process, enabling a better quality of health for a longer period of time.

So, that’s the skinny on the bennies. But what about the side effects? All things considered, what is the safest methodology to employ when it comes to fasting?

With all the benefits we’ve gone over here, is it possible that something so potentially beneficial for you could even have negative side effects?

While it’s true that anything is possible, side effects of fasting are minimal and reduced mainly to being hungry and the impact that can have on you overall mood, energy and stress response. When practiced safely, however, these effects can be significantly minimized.

Below are some useful tips to employ to help ensure a safe and successful fast:

    1. Keep your fasting periods and your expectations manageable. Your health is not something you play with or ‘power through’ so your fasting periods should be short and realistic to your daily demands and obligations. Here are some options to choose from:
      1. Caloric restriction to 500 calories per day for women, 600 for men, two days a week.
  • Same as listed above but only one day per week.
  • Fasting for a period of 16 hours (including sleep) and perhaps having your meals spread throughout the hours of 12-8pm
  • A 24-hr complete fast 1-2 times per week
  • Practice minimal consumption on fast days. Consuming a small amount of food on fast days (~25% of your caloric requirements), as opposed to cutting out food completely, can often reduce unwanted side effects and help keep hunger more manageable.
  • Stay hydrated. The potential for dehydration increases during fasting as you naturally meet some of your daily fluid requirements through food. A common practice is 8.5-13 cups of water during fast periods.
  • Stay mildly active. Going for low-impact walks or meditating on fast days can help make the time go by a bit faster and take your mind off the fast.
  • Ease back slowly. Concluding fasting with feasting is not recommended as doing so can make you feel tired and bloated. Ease back in to your daily food intake slowly and moderately.
  • Stop if your body demands it. Feeling a little tired or irritable during a fast is normal but if your body starts feeling unwell, it’s time to stop fasting. Do not power through it.
  • Protein is essential. When doing intermittent fasting, be sure and eat enough protein during your “feasting” period. 
  • Whole foods are essential. Eating plenty of whole foods during your non-fasting days can help sustain you during your fast.
  • Keep it calm. High-intensity activity is not recommended during fasting periods. Favor low-impact activity like walking or restorative yoga.
  • Do your homework first. There are certain individuals who simply should not fast. If you fall into one of the following categories, this means you:


    1. Adolescents
    2. Those taking prescription medication
    3. Older adults
    4. Women with history of amenorrhea
    5. Those with low blood pressure
    6. Individuals with history of eating disorders
    7. Those with blood sugar issues
    8. Women who are pregnant, breast feeding or trying to conceive
    9. Underweight individuals
    10. Those challenged with heart disease or type 2 diabetes


Ultimately, your approach to fasting depends on your goals and physical state. Those simply looking to shed a few pounds and balance blood sugar are good candidates for the IF option, while those looking for a complete immune system overhaul are more likely to lean towards the standard fasting protocol.

And as is the case with most everything, your primary physician should always be in the loop when attempting new health regiments because, as you now well know, there are certain individuals that simply should not fast.

1many of the testing being done related to fasting was performed on laboratory specimens and not as many on human cells. 


2PubMed: Intermittent Fasting vs. Daily Calorie Restriction for Type 2 Diabetes: A Review of Human Findings

3PubMed: Glucose Tolerance and Skeletal Muscle Gene Expression in Response to Alternate Day Fasting

4PubMed: Resting Energy Expenditure in Short-Term Starvation is Increased as a Result of an Increase in Serum Norepinephrine

5 PubMed: Effects of Intermittent Fasting on Body Composition and Clinical Health Markers in Humans

6NCBI: Heart Disease and Stroke Statistics 

7PubMed: Improvements in Coronary Heart Disease Risk Indicators by Alternate-Day Fasting Involve Adipose Tissue Modulations

8NCBI: Usefulness of Routine Periodic Fasting to Lower Risk of Coronary Artery Disease Among Patients Undergoing Coronary Angiography 

9Neurofitness: A Brain Surgeon’s Secrets to Boost Performance and Unleash Creativity

10PubMed: Intermittent Fasting and Caloric Restriction Ameliorate Age-Related Behavioral Deficits in the Triple-Transgenic Mouse Model of Alzheimer’s Disease

11Neuroprotective Role of Intermittent Fasting in Senescence-Accelerated Mice P8

12Fasting Cycles Retard Growth of Tumors and Sensitize Range of Cancer Cell Types to Chemotherapy

13PubMed: Effects of Intermittent Feeding Upon Growth and Lifespan in Rats

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