In this series I will explain how intermittent fasting works.
Intermittent fasting is popularly known by most people to be when you refrain from eating for at least 15 hours per day, this leaves you with a feeding gap of at most 9 hours.
There are different informational sources (books, websites etc.) and “experts” on IF who recommend different approaches. I intend to summarize what a few of them say, and add in some commentary of my own as well.
I will briefly list the implications of intermittent fasting here in part 1 to save time for those of you who just want the takeaways without deeply immersing yourself into the subject. For those of you who do want to learn more – read on, I’ll go more into depth and show you sources of where you can read more on IF.
The Implications of Intermittent Fasting
Most of the conventional wisdom about fasting is wrong.
Do yourself a huge favor and forget everything you heard. Most of this false information has been planted through brilliant advertising made by the food and supplement industries and propagated by ignorant people just spouting off information they know nothing or very little of.
Don’t forget that there are major incentives for these industries to get you to eat more unhealthy crap or push products on you that have no proof of producing any positive effects for your health. Most supplementation recommendations are inaccurate and spur you to use the product more than you need to so as to make you run out of stock quicker and purchase more of it.
It’s no coincidence that most meal replacement/protein supplements explicitly state that you should take them every few hours to “make sure your body doesn’t go into a catabolic state”, that’s actually the most common marketing pitch for those sorts of products.
- You can eat 1-2 bigger meals per day instead of 6+ small meals per day and get even better effects. Eating more small meals does NOT increase your metabolism due to TEF – the thermic effect of food.
- Breakfast is NOT the most important meal of the day. It’s actually the most harmful to the majority of people.
- By eating fewer times and therefore increasing the amount of time you spend in a fasted state, you lower your insulin levels which in turn increases the amount of fat you burn – which of course leads to lower body fat.
- Fasting leads to an increase in growth hormone. Growth hormone is a big deal and sort of like the magic pill of being healthy.
- Your body is NOT limited to consuming 30-40 grams of protein per meal. Don’t be overwhelmed by “broscience” of consuming 3+ protein shakes per day. Your body digests protein at a rate of about 3-10 grams/hour depending on what sort of sources the protein comes from and what your meal is composed of. E.G Whey protein is absorbed quickly at a rate of 8-10g/h while egg protein is absorbed slowly, at about 3g/hour.
(I used to drink 2-3+ protein shakes per day and it led to me putting on body fat and having stomach problems that I am now in the process of correcting. The stomach problems manifested itself in me being bloated, gassy and occasionally having stomach aches. Don’t drink poor quality whey protein too much.)
- You become more clearheaded and productive as an immediate effect of not constantly digesting food from eating every 3 hours or so.
Most people have no idea what it feels like to starve. You can go over 72 hours without food without it being particularly unhealthy, though I wouldn’t recommend it. What most people refer to as “hunger” is just a hormonal habit that they have enforced over the years.
- By snacking (especially sugary foods and most carbs in general) your insulin levels are raised and it makes you hungry even though your body doesn’t need to eat.
High insulin levels make your body store fat. Sugars make you fat, not saturated fats.
- You may feel hungry or weak in the first week or two from making the adjustment, but it will quickly pass, at least it has for me the times I have shifted to IF.
Now let’s review my notes from the most famous book on IF, Eat Stop Eat – which promotes fasting 24h one day per week.
Eat Stop Eat by Brad Pilon – Key Points:
- There are only two absolute truths related to nutrition & weight loss:
- Consuming fewer calories than what you need for maintenance lead to a decrease in weight.
- You are either in a fed or fasted state. You are either in the process of eating and digesting the food you have eaten – or you are burning stored body fat.
Everything else is up for debate.
Your basal metabolic rate is mostly determined by how much muscle mass you have, therefore strive to increase muscle mass even if your ultimate goal is to lose weight.
(This is why I say that cardio sucks as a vehicle for weight loss.)
You most definitely do not need to eat every three hours for fear of losing muscle or slowing down your metabolism – there was actually a supervised experiment in which the test subject fasted for 72 hours without decreasing his resting metabolic rate.
Metabolism is linked to your bodyweight, not so much with what you eat.
(Stop concerning yourself with silly diets that are supposed to increase your metabolism and make you lose weight, it’s an utter waste of time compared to gaining muscle and increasing your basal metabolism. Always apply the 80/20-principle and use time efficiently.)
Fasting does not negatively affect anaerobic exercise like weight-lifting in the gym. However it is less efficient when it comes to prolonged aerobic exercise like marathons because your body’s storage of glycogen depletes after around one hour.
Point being – you do not have to eat before a workout, it is actually only more likely to slow you down once you are used to IF. However you may need to consume some protein.
(A lot of people recommend consuming BCAA (branched-chain amino acids) as it shouldn’t start your digestion system prior to the workout or during. I don’t do that anymore though, and I have noticed no difference.)
A study of men and women who consumed 800 calories/day and 80 grams of protein/day for 12 weeks showed that there was no loss in muscle mass for as long as they exercised with weights 3 times/week. If you are fasting or under severe caloric restriction for a prolonged period of time (over 3 days) you are likely to start losing muscle mass if you don’t do intense anaerobic exercise.
The hunger most people experience is mostly a hormonal response.
Starvation on the other hand is something very few people in modern day society have EVER experienced.
I’ve fasted over 72 hours and I got nowhere close to starving!
This “hormonal hunger” is usually the result of high insulin levels and habitually programmed patterns of hormones due to eating certain amounts of food at specific times – this can easily be changed in a matter of weeks.
Health benefits associated with short-term fasting according to scientific studies:
- Increased lipolysis & fat oxidation
- Increased Uncoupling Protein 3 mRNA
- Increased norepinephrine & epinephrine levels
- Increased Glucagon levels
- Increased growth hormone levels.
- Maintenance of skeletal muscle mass
- Decreased blood glucose levels
- Decreased body fat & body weight
- Decreased insulin levels & increased insulin sensitivity
Insulin’s main role in the body is to store nutrients – including fat!
- Whenever your insulin levels are high, your body can’t release fat from its fat stores.
- Eating food (especially starchy and sugary food – carbs) raises your insulin levels.
Research of people who fasted for 72 hours showed that plasma insulin fell to a level lower than half of the starting levels. 70% of this drop in plasma insulin levels happened within the first 24 hours.
Lipolysis is the process of how fat is released from its fat stores and into the bloodstream. Fatty acids then go to the mitochondria in your cells and go through oxidation and are ultimately converted to energy.
- Lipolysis and oxidation increases by 50% after 24 hours of fasting.
Insulin is the dominant hormone in causing you to store calories, while glucagon is the dominant hormone in burning fat. They are sort of like opposites.
Glucagon does other good stuff as well except for burning fat – such as lowering production of LDL (“bad cholesterol”), maintaining blood sugar levels by burning fat, and lowering the amount of fluids your body is storing.
Most people are always running on glucose due to having high insulin levels, this means they are constantly in a “fat storing mode”. If you regularly fast you will shift toward a metabolism dominated by glucagon and burn fat instead.
Fasting leads to increased levels of epinephrine and norepinephrine. (AKA adrenalin & noradrenalin). This makes you feel more awake.
This effect is usually palpable for me, it’s awesome when you want to get intense and really immerse yourself into work or a task for a couple of hours
According to Martin Berkhan of Leangains, IF does not increase cortisol. (nr 8)
Intermittent fasting increases growth hormone levels by close to 600%.
There are other studies where the levels have gone much higher than 600% during a 24 hour fast.
By fasting 24 hours at least one or two times a week, you are able to lower you intake of calories by 20-30% without regard to what you are eating.
- Example: If you eat 3000 calories every day while doing intermittent fasting, this leads to a reduction of 750 calories per day, effectively decreasing your net calorie consumption to 2250 calories/day! 750 calories is what 2.5 cheeseburgers from Mcdonalds equate to.
Now you know why eating sugar and eating many small meals every day absolutely SUCKS.
Here’s part 2 where I summarize the information from the book Fast 5.