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Intermittent Fasting - The Basics

Updated: May 4

I was first introduced to intermittent fasting unknowingly. It was through Ramadan, a holy month in the Islamic calendar, in which Muslims fast from sunrise to sunset, and in doing so refrain from all worldly pleasures including but not limited to eating and drinking, intimate relations, enacting the cardinal sins, etc. Essentially a will testing and gratitude building month in which we opt for conscious betterment of our lives.


I remember the judgment I used to get from kids when I was young over the "starvation" factor. Calling Islam all synonyms of torturous and I honestly questioned if it was even though I knew the underlying reasons for this one short month of diligence. Talk and chatter from the outside will do that to you - But now?! Intermittent fasting is all the rage and is so far from the fad diets that come and go because it has been thoroughly scientifically proven and more importantly experience has proven it to be massively beneficial to our health in countless ways.


In the modern-day IF became popularized by

  1. Dr. Michael Mosley’s TV documentary - Eat, Fast, Live Longer,

  2. Kate Harrisons - the 5:2 Diet, and

  3. Dr. Jason Fung’s - The Obesity Code.

And the underlying conclusion amongst all sources is that IF results in better fat loss, less muscle loss, improved cardiovascular health, better glucose control, more autophagy and restoration of stem cell function.


There's so much to say about IF but in this post, I want us to do a quick overview of the pure basics of its benefits and easy changes to the typical Ramadan based fasting scheme that could completely transform the experience into one even greater for our bodies.


Let's start by breaking down the basics and benefits of fasting purely in terms of weight and body composition.


IF can be broken down into these major categories:

  1. Alternate day fasting - where you fast one day, eat the next, or

  2. Time-restricted feeding - where you fast for 16-20 hours, eat in the remaining 4-8 hour window.


Besides religion and things like practicing better food control, or choosing to free up the day for full focused work instead of the distractions and energy requirements of eating and digesting food, people intermittent fast for the proven health benefits.


Studies on the topic in rats have shown better weight loss, improved CV health, neuroprotective effects, decreased cancer risk, and increased lifespan when compared to a normal diet or feeding schedule. But studies in humans, on the other hand, showed weight loss, lowered blood pressure and lowered cholesterol in obese patients specifically, following alternate day fasting, while those who were lean in weight, in fact, didn’t see so much of a benefit, and just maintained their stats.

The studies went on to find that IF wasn’t a markedly superior option to continuous energy restriction when it came down to weight loss In particular, but was in terms of every other category. The periods of deprivation act like preconditioning stress to warm you up for larger stresses down the line, should they occur. Kind of like vaccines or exposure to germs.


A big concern people have is how this form of eating could keep muscle anabolic - in other words - how to not lose muscle when eating in this seemingly restricted way. This concern comes from the understanding that if your body is deprived of nourishment for long enough, it has to turn to its stores for energy. Let's break down these forms of stored energy:

  • Carbohydrates get stored in liver and muscle cells in the form of glycogen. When this energy is needed, glycogen gets converted to glucose for use.

  • Fats are stored in the body as cells called adipocytes. The number of adipocytes in the body is set and determined in late adolescence and rarely changes into adulthood - just the size of these cells changes according to how much fat is being stored. When metabolized for use - the fat cells are broken down into glycerol and fatty acids, and then absorbed in the liver, kidneys, and muscle.

  • Proteins don’t actually get stored in the body, and so get broken down into amino acids, which then get converted into glucose or ketones for use. Only in periods of starvation would these amino acids be used as an energy source though.


So bringing it back to how not to lose muscle mass - It's a common misconception that you have to eat every few hours to keep your muscle anabolic, aka built and strong, when in fact a 2006 paper found that even 40 hours of fasting had no significant effect on the negative regulators of muscle mass and didn’t cause significant atrophy. Meaning - fasting for almost 2 days straight without any muscle fuel had next to no effect on your existing muscle. This is because a fasted state will deplete liver glycogen, or stored energy from the sources we just mentioned first - in 24 hours only working through half of that store too, meaning muscle stores haven’t even been accessed yet!


A similar concern is that you must eat every few hours to not gain weight. This concern doesn’t have scientific backing but the thought process is more likely that if you wait too long between meals you’ll end up opting for the biggest baddest most calorie-dense comfort food possible when you do eventually eat. Ideally, however, anyone on a health journey would be more carefully choosing their food at any given time.


Another issue that comes up is the potential slowing of your metabolism if feeding is infrequent. The science behind this worry is the understanding that thermic activity in the body speeds up after a meal - this activity being the driving force powering your metabolism. But, the rise in thermic energy is proportional to the caloric content of a meal, not the meal frequency - so technically, eating a single larger meal would result in just as much thermic burn as multiple smaller meals, meaning your metabolism changes according to caloric intake, not meal timing.


And of course we can’t miss the biggest misconception by far - that breakfast is the most important meal of the day. Looking at commonly cited studies making this claim you’ll see that a lot of the studies looked at children and adolescents, which is a very broad category, to begin with, and only made the conclusion that the kids who skipped breakfast were generally overweight, and the kids who didn’t had better overall habits, also generally. This is so misleading because this single observation of skipping breakfast is being made causation of obesity which is a grand assumption. This study had no restrictions in terms of calorie intake or the quality of food being eaten at breakfast, nor for the rest of the day. It simply said - eat or don’t eat breakfast and record your food intake for the day no matter what it is. More likely - the healthy habits in the kids eating a morning meal is what is keeping them at a healthy weight, and the kids who skip breakfast probably have naturally disordered eating habits and make choices later on in the day fueled by convenience, or are not as active or have irregular sleep cycles leading to decreased energy expenditure.


In my opinion, a better study looked at the effects of 8 weeks of IF on the metabolism, strength, body composition, inflammation and CV risk factors in males doing resistance training. So this looked at one specific category (resistance training males) and controlled for macronutrient and caloric intake. It found that after the 8 weeks the subjects doing IF showed decreased fat mass, improved healthy biomarkers, and maintained lean muscle mass. The study didn't stratify along with the original weight of the participants, so it is unclear how this result of lowered fat mass/maintained muscle mass compares to the earlier mentioned study which resulted in maintained weight among lean individuals, and significant improvements only in obese participants.


As you can see, no matter what the concern surrounding this grueling, focus-testing practice, it is greatly outweighed by multiple potential benefits. And if science doesn't convince you - try it out for yourself! If you want to follow the 16:8 fast for example, stop eating 4 hours prior to bedtime, sleep for 8 hours, and eat 4 hours later! It's as simple as having an early dinner, getting good sleep, and skipping breakfast or having a late one! And the best part is that while you should obviously eat a balanced, nutritious diet, you technically could eat as you already are as long as it fit into your 8 hour window! Celebrities like Beyonce, Terry Crews, J Lo and Hugh Jackman all swear by IF to get into shape fast and honestly, if it's good enough for Wolverine, it's good enough for me.



Disclaimer: This content is strictly the opinion of Dr. Mashal Khan and is for informational and educational purposes only.The information discussed is not intended to diagnose, treat, cure or prevent any specific disease or medical condition. It should not be used for or in the place of medical advice or treatment from a personal physician. All viewers of this content, especially those taking prescription or over-the-counter medications, are advised to consult their physicians before beginning any nutrition, supplement or lifestyle program and with specific health questions. Neither Dr. Khan nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content.

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