Intermittent Fasting – Full Guide and Advanced Concepts
Intermittent Fasting has rocked the nutrition world and provided new perspectives. In this actionable guide, you will discover how you can benefit from the latest discoveries, including but not limited to:
- System overview and background
- The benefits of doing intermittent fasting
- How does IF works with weight loss, strength and muscle gains
- The various protocols and how to start with each one
- The LION method, and how to use intermittent fasting to speed up weight loss further.
Let’s start with a bit of background.
What is Intermittent Fasting?
Intermittent Fasting (IF) is a pattern of eating that defines periods of eating and fasting. It’s not a defined diet but rather a dietary structure which can accommodate many different types of food. You can use IF to improve your health and fitness.
Intermittent fasting is demonstrated to a large degree in the animal kingdom. Unsurprisingly, it is also known that human evolution also mimics this structure closely. This stands in direct contradiction to modern culture who preaches small meals every few hours or that being a little hungry is a bad state.
Intermittent fasting is revolutionary due to the fact that it challenges modern approaches to nutrition and diet. Statements like “breakfast is the most important meal of the day” or “6 to 8 meals day to boost your metabolism” simply do not stand shoulder to shoulder with IF. Most methods involve at least a 12 hours fasting period, which also means skipping breakfast and not being able to eat 6-8 times a day. Despite of this, we see a tremendous improvement in markers of health and longevity, as well as bigger potential for weight loss and strength gains.
Sounds interesting? We hope so!
What are the benefits of intermittent fasting?
- Fat Loss that extends to stubborn areas (belly fat / love handles)
- Improved mental clarity and focus
- Lower Insulin Levels, blood sugar levels and the potential to reverse type 2 diabetes
- Increased Growth Hormone
- Increased BDNF (Brain-Derived Neurotrophic Factor) and therefore neurogenesis
- Naturally drives ketogenic states and helps fat adaptation.
- Reduced inflammation
- Gut repair
- Promotes apoptosis (natural cell destruction)
- Increased markers of longevity (live longer)
- Improved lipid profile and reduction of blood cholesterol.
- Helps prevents disorders later in life such as Alzheimer
- Helps improve blood circulation
A lot of those benefits are linked… let’s break it down.
Does intermittent fasting work for weight loss?
Intermittent fasting works for weight loss, primarily by lowering Insulin (which promoting fat storage). Intermittent fasting has been shown countless of times to help with weight loss. That includes stubborn fat, such as the one on your belly and love handles.
Interestingly, it’s less to do with a calorie reduction. In fact, many studies examined the change in calorie consumption and found out that their subject ate similar amount of calories through out the day by adding to the meals. So instead of having 3 medium size meals, they had 2 meals which were somewhat bigger.
In my opinion, this is one of the biggest faults of many modern day IF methods. They fail to acknowledge that calorie reduction is not the main driver behind intermittent fasting results. This is addressed in detail in the LION Protocol (more details down the page).
The primary way intermittent fasting helps with weight loss is by lowering blood sugar levels (as there is no food to break) and therefore reduce the levels of Insulin in the body. This sets up a chain of reactions over time:
- With low Insulin comes heightened adrenaline response (fight or flight) and better growth hormone secretion.
- With prolonged reduction of Insulin, we can see inhibition of Alpha-2 Receptors on fat cells. These alpha-2 receptors act to block lipolysis (fat-breaking) and they are most abundant in the abdominal tissue and around the obliques (read: belly fat and love handles). By inhibiting them, we can gain better access to a layer of fat which is otherwise stubborn.
IF also helps us tremendously in triggering apoptosis (elimination of small fat cells so they don’t have the chance to regrow). This is of course very important for people who lose weight and find that it comes back as you may shrink the fat cells (and lose weight) but until you eliminate them, they can grow back with ease.
IF tremendously helps your cells become adapted to fat as a source of energy. Because no sugar is available, the mitochondria has to make changes over time to be able to utilize body fat (and as a result, ketones) as a source of energy.
Lastly, marked improvements in blood circulation (especially to the abdominal tissue) and gut repair, means our entire metabolism (read: gut health) can work better, absorb food better, increase our mood, our energy and improve our sleep as well as reduced systematic water retention and inflammation. All of which are also related to weight loss.
Can you build muscle while intermittent fasting?
Building muscle while doing intermittent fasting is possible but not efficient because you will get less protein synthesis and less metabolic stimulus (via pump). You can however achieve peak strength gains and you will not likely lose any muscle during intermittent fasting.
During a fast, your senses are sharpened (like an animal in nature, getting ready to hunt) and your adrenaline goes up. That means your strength levels can peak and you can experience strength not usually available to you. This is why things like fat loss, mobility and strength training (esp… calisthenics) can go along way when fasted.
At the same time, tasks that requires repetitive nature and loading, like muscle building, will suffer.
Because your muscle glycogen levels are going to be lower, your wouldn’t be able to pull a lot of water into the muscles and won’t be able to get a good pump. A good pump is paramount to building muscle as it’s an internal signal from within the muscle cell to grow out. It also means you will have less “juice” and fatigue faster on high rep training, which is needed for bodybuilding.
Another concern is amino acids availability which is one of the primary stimulus for protein synthesis. During a fast, you won’t be able to eat protein / amino acids (if you do.. you’re losing the benefits of higher than usual peak strength), which means your blood won’t be saturated with amino acids. As amino acids are the building blocks of protein, you will need to have good levels of amino acids in your blood before, during and after training and it’s simply not possible while doing intermittent fasting.
If your main focus in on muscle building, I suggest you skip intermittent fasting and stick to a few small meals a day, high in protein and carbs. Yes, this is not the optimal strategy for weight loss or longevity but it will help you build muscle mass. Then, periodically, when you rest from your muscle building effort, you can practice intermittent fasting and enjoy some of its benefits without sacrificing your effort for little gains.
How does intermittent fasting helps with longevity?
Recent studies show that intermittent fasting can help extend your lifespan and slow down the aging process. This is because fasting can help your body regenerate and repair on at the cellular level. Fasting also increase BDNF hormone which promotes cognitive health.
Not surprisingly, if you can improve your lipid profile, gut health, cholesterol and hormonal balance, you might also experience better overall health. Another less known effect of intermittent fasting is increase in a growth hormone like equivalent for brain matter, BDNF.
BDNF (Brain-Derived Neurotrophic Factor) can help neurogenesis, or the creation of neurons in the brain. This is the same neuroprotection you get from good exercise, eating fish and creating mental stimulation. It can help protect you from degenerative diseases like Alzheimer and dementia.
This is a small part of why we get stimulated and focused (primarily via Adrenaline release) after a long fast, it sharpens your brain.
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How can you start with intermittent fasting?
There are a few popular ways you can start with IF. I’m going to details the protocols below, including my proprietary method called the LION Protocol.
- Eat-Stop-Eat – 24h Fasting
- 16/8 – Lean Gains
- 5:2 Diet
- Alternate-Day Fasting
- The Warrior Diet
- Non Structured (meal skipping)
- The LION (Low Insulin Optimized Nutrition) Protocol – our favorite method
Eat-Stop-Eat – 24h Fasting
Eat-Stop-Eat is the work of Brad Pilon. A great deal of the research into intermittent fasting was done with a similar 24h format. In a way, this method has paved the way for others with initial and promising summary of the research.
- 24h Fasting, once or twice a week. Essentially, stop eating after dinner (say 8:00pm) one day, and skip all food until the next dinner (at 8pm the following day).
- Water, Coffee, Tea and non-alcoholic drinks are allowed but no solid food. Those drinks are allowed as long as they are raw (i.e. with nothing added, no milk, no cream, not even sugar)
- The plan permits artificially sweetened drinks.
- Normal sized meals (don’t over eat to compensate)
- Exercise is encouraged (especially beyond the 18h as there are additional benefits Brad mentions)
My verdict on it is mixed:
- It’s not a bad system, it will work – but it will work differently for people (explained in a second)
- It’s hard to do. 24h fasting can mess with you.
- I think that by allowing artificially sweetened drinks, it is killing a great deal of the benefits. Yes, it might be easier for people with a sweet tooth but this system is not about easy. Artificially sweetened drinks can not only still cause insulin to spike (and a lot of the benefits associated with fasting to drop), they are also very harmful for your gut bacteria.
16/8 – LeanGains Protocol
This method (by Martin Berkhan) became popular as it is easier to do. It goes by the name of the LeanGains protocol or 16/8 Intermittent Fasting.
- Men fast for 16 hours (and eat for 8 hours), women fast for 14 hours (and eat for 10 hours).
- Easy to do on a daily basis.
- You are allowed water, coffee, tea with a splash of milk / sugar – as long as it’s under 50 calories.
- Zero calorie drinks (like diet sodas) are allowed.
- BCAAs are allowed and so is whey protein
- Training at any point during the day, a few times a week.
My verdict on it is highly mixed:
- I love that it’s accessible and anyone can do it. It’s basically a matter of skipping breakfast.
- You may be getting less benefits but you are getting them every single day.
- I don’t recommend doing it in this format at all. Not because the timing is bad, but rather because the compensations the system allows can effectively ruin a lot of the adaptions and benefits it promotes.
- Example 1: It doesn’t matter if your nutrients are from solid food or if you drink them, they are still creating the same response. In this case, they will still create an Insulin spike – even at “50 calories or less” as some sweeteners can have 0 calories and still create an Insulin spike. If your Insulin isn’t at rock bottom, you are shooting yourself in the legs in regards to the benefits associated with weight loss, including growth hormone and inhibition of alpha-2 receptors.
- Example 2: I’ve seen posts on LeanGains promoting diet sodas, you know… because it has zero calories. Well… Not only many of those “zero calories” substitute still create an Insulin response, they are also terrible for your gut health and microbiome. Overtime, this will have a very negative effect on your health.
- Example 3: if you are having milk in your coffee or protein powder.. it’s still food. That means you have now broken the fasted state. Not only that, small amount of foods during fasting can promote hunger.
- It should be said that BCAAs can be ok (they metabolize directly in muscle tissue). However, I don’t know anyone who is happy to drink raw BCAAs or take massive tablets. Most people who take BCAAs do it by buying mixed up drinks which uses sweeteners. I can’t blame them because I know how vile it tastes (it’s all due to L-Leucine, the most effective of the branch chained amino acids) but if you throw in sugar / sweeteners with something good, you just eliminated the good effects with some bad ones.
The 5:2 Diet
The 5:2 diet is a bit of an abomination 🙂 Made popular by Michael Mosley in his documentary about intermittent fasting for the BBC.
- Eat normally for 5 days a week
- For 2 days a week, restrict your calories to 500 calories for women or 600 calories for men per day.
- No actual structure, you could have 6 meals of 100 calories or 2 meals of 300 calories – this is not really fasting.
Incidentally, working within London myself, you meet people and one of my clients has been directly involved with making this documentary so I have a bit of inside knowledge.
As you can expect, the BBC isn’t always the most extensive in their research and as it turns out, they had a lot more data they didn’t explore or implement. Why you ask? Well… apparently according to mainstream media standards, promoting a structure that may be effective for weight loss may also encourage those with anorexia or bulimia to take part and promote self hatred and body image issues.
So as you can see, research into this diet is lacking, their results are lacking and it would be interesting to point out that there has been no scientific research to say the benefits of restricting calories is in anyway similar to those of fasting. With this diet, we take a step back from intermittent fasting and worry yet again about calories.
Fasting every other day, which can produce a lot of results but it’s not easy for most people and going to be hard to promote exercise on a platform like this, which will not provide the full spectrum of possibilities.
- Alternate days of eating with days of fasting
- Some versions of this diet allow you to have 500 calories equivalent meals in either 1 or 2 meals. This is not a lot of food at all.
This is a strict diet, which means you will often go to sleep hungry. I can see it affect negativity on gut health with most people diets not being prioritized for prebiotics. I don’t like that it doesn’t really promote exercise which is a big missed opportunity as fasting creates optimal conditions to improve metabolic responses in training. Instead this seems to be focused on diet only and calories approaches which I do not approve of.
The Warrior Diet – 20:4
This is a primal approach by Ori Hofmekler. Basically, it revolves around a longer fasted state of around 20 hours and smaller feeding window of around 4 hours.
- Semi-Fast all day – you can eat small amounts of dairy, vegetables and non-calorific drinks.
- ,Eat a HUGE meal at night – Paleo style preferred but nothing is restricted. You have 4 hours to eat whatever you want but you are encouraged to prioritize raw veggies and animal products.
This diet isn’t strictly intermittent fasting but it does give the body some of the benefits as if you stick to that diet, you likely won’t feel hungry and end up fasting for a few hours between bites. It’s an interesting approach but sadly, it can not produce the exact same benefits from prolonged fasting, such as increased weight loss.
Non Structured (meal skipping)
This is not a bad approach, but it lacks structure and results will vary to a large amount. Some people will use it well, others will abuse it well.
- Don’t plan anything but try to skip a meal and not fill guilty about it. For example, if you’re not hungry or don’t really want to cook.
- Say you worked late and accidentally skipped breakfast or lunch, you might as well be aware of the benefits and not ruin it with a snack or a latte from your favorite coffee shop. Instead, try and prolong the fasted state for as long as possible to rip some of the benefits.
My verdict is.. it depends.
Obviously, this is spontaneous intermittent fasting, not a structured one. It’s doing things without planning which could work – if you ended up doing them right (as if they were structured) or won’t work, if you ended up mixing things up.
If you skip a lot of meals, and use prolonged fasted states to also train the right way, this could work for you. Otherwise, you’ll probably end up worse.
The LION Protocol (Low Insulin Optimized Nutrition)
This method (proprietary to BellyProof) is all about optimizing for low insulin and high growth hormone, both of which have opposite relations. Its not dealing with calories but rather how to optimize those state for maximum fat burn and minimum fat storage.
We optimize around 12h fasting. It’s true that longer fasting up to 18h can be optimized for even better weight loss but it’s unrealistic to expect most people to fast for 18 hours a day – every day. If we had to choose 18h twice a week for a massive boost of growth hormone as oppose to 12h, every single day, we’d get more boost from the moderately high 12h fast.
Why did we need another protocol?
This is the proprietary protocol that I developed for BellyProof. I wanted to marry the effusiveness of the twice-a-week eat-stop-eat (24h fasting with insane hormonal benefits) together with the everyday ease of a protocol like LeanGains, which in my view is a good base but shoots itself in the foot on the hormonal side by allowing all those compensations.
The other thing that I found frustrating was the old mindsets, still centered around calories, metabolism and “breakfast is the most important meal of the day”. This is in complete contradiction to:
- Calories being determined not to be the driving factor (most people ended up eating the same amounts, just with different timing, and still see great benefits from the structure – despite having similar amount of calories, hence they are not the driving force).
- In most scenarios, breakfast was skipped.
- Starvation mode wasn’t documented in any of the cases, implying the old approach the fitness industry had towards metabolism, might need a good review.
If you sit and read through the 1000s of research papers, looking into how intermittent fasting affected various groups under various conditions, it usually goes like this:
- Here’s the protocol they followed, when they ate, when they didn’t eat, what they were allowed or not allowed to do during fasting and the exercise they did or didn’t do.
- Here’s a list of changes that were measured when running their blood work. Changes to hormones, enzymes, lipids, cholesterol and other biochemically relevant compounds. They also report what changes were measured as far as increased strength, lipid oxidation and factored in self reported information such as mood, hunger and energy.
If you stopped there, you’ve got everything you need to drive conclusions about what makes the protocol better or worse. Instead, most of the research papers list one more thing – calories.
They state clearly we’ve got those amazing benefits, and oh… yeah.. they also had this amount of calories or that amount of calories. The focus now became calories even though we had a ton of information pointing that calories were hardly a factor (as people often ate the same amount and still saw benefits). It’s not just a miss, it’s a mess!
I felt I needed to look at the information with a fresh set of eyes, without considering calories, but strictly considering everything else. If you think this is unreasonable, you may not be aware of the many faults the calorie theory presents and how it came about. You might want to click here to read about calories in a different light.