by Siim Land
In fact, growth hormone increases exponentially by up to 2000-3000% at the 24-hour mark. #ARMEXPLOSION (See Figure 60)
Figure 60 Fasting increases the amount of growth hormone surges during the day
When you look at the amount of GH increase then the micrograms aren’t that large, but you wouldn’t experience anything like that in a regular metabolic state. Not eating gives you something you wouldn’t gain from regular eating. This boost is actually going to last for the upcoming several hours.
Another hormone that’s going to help you build muscle is testosterone.
Short-term fasting has been shown to increase Luteinizing Hormone (LH), which is a precursor to testosterone. In a study done on obese men, LH increased by 67% after 56 hours[394].
Another study found that obese men saw a 26% increase in GNHR (Gonadotropin-releasing hormone), which is another testosterone stimulant[395]. The same study found that men who were working out saw a 67% increase in GNHR, which led to a 180% boost in testosterone.
So, there’s plenty of hormonal benefits to fasting and I’d suggest that if you’re suffering from low testosterone or you can’t seem to build muscle, then it’s just because your endocrine system is unable to produce its own testosterone. Some careful and strategic intermittent fasting can help your body to not be so lazy so to say and jack up your muscle building pathways.
Nevertheless, there are many people saying that they’re losing muscle while fasting. Why is that?
It’s important to realize that not all weight loss equals muscle loss. Losing weight doesn’t mean you’re burning fat either. The goal is to lose weight at the expense of fat tissue and fill it up with muscle thus ending up with a positive NET gain.
With that being said, it doesn’t mean you can’t lose muscle while doing intermittent fasting. Of course, you can and you will if your body feels the need to do so. There are 2 reasons why you may begin to break down your lean tissue.
(1) Gluconeogenesis While Fasting
First is gluconeogenesis – the conversion of protein and fat into glucose.
Gluconeogenesis is driven by demand not by supply, which means that it happens when your body needs glucose for survival and the only source of glucose it can find is its own organs and muscles.
The reason you may trigger gluconeogenesis is that you don’t have access to other fuel sources, like fat. Your body isn’t keto-adapted to burning ketones yet and the next best thing it can think of is protein.
That’s why you’d want to get into ketosis as soon as possible when you’re doing fasting or even when maintaining a caloric deficit. The ketogenic diet will make you burn exclusively your own body fat while preserving muscle because ketones give more energy to the brain, which spares protein.
After you flip the metabolic switch of starting to use more ketones for fuel, you’ll increase fat burning and protect your muscles because the body has access to an abundant fuel source which is your own body fat.
(2) Autophagy and Muscle Loss
The second reason why you may lose muscle while fasting is the inhibition of autophagy.
Studies have found that autophagy is needed for maintaining muscle mass[396].
If you’re doing a caloric restriction diet but blocking the effects of autophagy, then you’re going to keep yourself in a semi-starvation state because your body will never switch into ketosis. This leads to gluconeogenesis and so on – the bad stuff.
If, however, you allow autophagy to kick in, whether that be through strict water fasting or a fasting mimicking ketogenic diet, then your also stimulating the other growth hormones we’ve been talking about so far and it’s going to preserve your muscle.
What it means is that if you want to burn fat, or if you want to prolong your lifespan, then you’re actually better off by avoiding all calories whatsoever.
Even as little as 50 calories of 2-3 grams of leucine will stop autophagy and shift you into a fed state. It’s going to be better for fat loss, for muscle sparing and for longevity, to avoid all calories during your fasting window. That goes back to the idea of timing your calorie intake more in the post-workout scenario wherein you’ve reaped the benefits of fasting ketosis and are now prone to recover.
That’s why when dieting or staying at a mild caloric deficit, it’s better to stay in ketosis for at least most of the time because it’ll maintain more lean tissue while still enabling the burning of body fat.
One study in the 70s compared 3 diets with the same amounts of 1800 calories and 115g protein but with carbohydrate ratios of 30-g, 60-g, and 104-g[397]. After 9 weeks of dieting, the 30-g group lost 16.2 kg, the 60-g group lost 12.8 kg, and the 104-g group lost 11.9 kg. What’s more, the 30-g group’s weight loss came from 95% fat loss, for 60-g it was 84%, and the 104-g 75%. These findings show that lower carb ketogenic states can promote more fat loss at the preservation of muscle mass.
There are several possible mechanisms by which a ketogenic diet preserves muscle mass and prevents protein catabolism.
Low blood glucose stimulates the secretion of adrenaline, which regulates skeletal muscle protein mass. Adrenaline’s been shown to directly inhibit protein breakdown[398].
Ketone bodies provide a plentiful source of fuel to brain and muscle tissue, which suppresses protein oxidation and gluconeogenesis of muscle. In fact, BHB has been shown to decrease leucine oxidation and actually promote protein synthesis in humans[399].
Dietary protein consumption also has a much greater muscle sparing effect than carbohydrates. Eating protein increases protein synthesis by increasing the availability of amino acids in the blood. When eating at a caloric deficit, higher protein intake has also been shown to reduce muscle loss and promote fat loss[400].
One of the branched-chain amino acids leucine has also been shown to stimulate protein synthesis via the insulin signaling pathway without actually needing carbohydrates[401]. Leucine’s metabolite HMB has also been found to have anti-catabolic effects[402]. High protein diets have been shown to increase muscle protein synthesis despite the reduced levels of insulin[403]. A ketogenic diet isn’t necessarily high in protein but it’s still can provide the individual with all the essential amino acids and complete protein sources.
Can Fasting Make You Build Muscle
But what about the opposite? Can fasting actually make you build muscle?
It depends on how hard you train and how many calories you eat during your feeding window when you’re not fasting. I’m going to leave the nutrition aspect for the coming chapters because I want to cover the hormonal side of how it’s possible.
Studies have found that fasting lowers the expression of mTOR and IGF-1, which are both needed for cellular growth by increasing one of their inhibiting proteins called IGFBP1[404]. Within 12-14 hours of fasting, SIRT1 gene regulation starts rising which will begin to suppress mTOR and AKT[405][406], thus down-regulating mTOR mediated protein synthesis.
TOR has quite a detrimental role in anabolism. Inhibiting mTOR blocks the anabolic effects of resistance training and prevents muscle growth[407]. mTOR is clearly anabolic but also anti-catabolic. It’s going to protect the body against the harmful effects of cortisol and glucocorticoids on muscle tissue[408]. Fasting is one of the most anti-TOR things there is because of upregulating AMPK and depleted amino acid availability.
Although fasting increases growth hormone exponentially, it also decreases serum IGF-1 levels, which again decrease the body’s anabolic state[409]. This may seem paradoxical at first because we know that the production of IGF-1 in the liver and muscles gets instigated by the release of growth hormone from the pituitary gland in the hypothalamus. What gives?
Truth be told, growth hormone is not as much of an anabolic hormone as it is an anti-catabolic one. GH has many fat burning properties that promote catabolism but its main role is to still preserve lean tissue not build it. The muscle building properties are triggered by IGF-1 and mTOR both of which get decreased while fasting. However, it doesn’t mea
n you can’t build muscle.
Muscle growth results from the positive balance between muscle protein breakdown (catabolism) and muscle protein synthesis (anabolism). See Figure 61. You can stay in a highly catabolic state most of the day (fasting) if you compensate for it with enough anabolic stimuli (eating). It’s possible to build muscle with a time-restricted feeding schedule, even with eating just one meal a day. Whether or not it’s the most optimal thing for muscle growth remains to up for debate.
Figure 61 Muscle Hypertrophy Results from
a Positive Gain of Muscle Protein Synthesis over Muscle Protein Breakdown
If you’re trying to maximize your genetic potential for lean muscle mass, then it’s naturally going to be easier to do so with a more frequent eating schedule. Likewise, it would be possible to go through periods of more anabolism followed by brief periods of higher catabolism that can lead to a positive muscle building condition because of practicing intermittent fasting.
The rationale of trying to build muscle and strength with intermittent fasting isn’t oriented towards maximizing muscle growth or performance. It’s about prioritizing longevity and not over-stimulating the anabolic effects of mTOR all the time.
That’s why you can’t build muscle in a fasted state directly – it’s not even supposed to happen as the goal is catabolism. However, the anabolic state comes from the feeding stage wherein you nourish the body and drive quality lean muscle gain.
It may seem like pushing a boulder up a hill as Albert Camus described in his novel The Myth of Sisyphus. In Greek Mythology, Sisyphus was the king of Corinth who was sentenced to push a boulder up a hill because of his lavish lifestyle and deceit. Every time he started to reach the end at the top, the boulder would roll down the hill again. Sisyphus was made to repeat this process for an eternity, never getting anywhere. Camus used this story to depict the notion of the absurd where men seek futile meaning and clarity in an indifferent world devoid of eternal truth.
Doing intermittent fasting for muscle growth may indeed seem like pushing a boulder up a hill because it doesn’t send an anabolic signal for building lean tissue. However, it can still facilitate a positive increase in lean mass if done right. In fact, it’s much more favorable in terms of longevity-oriented muscle growth and other health benefits. It’s not as anabolic as taking steroids or eating high carb high protein 6 times a day by any means but the gains will be quality and leaner. The process may be slower but like Camus said: “One must imagine Sisyphus happy”. Which means you should still enjoy the journey despite the struggle and adopt the right long-term mindset.
I myself have been doing intermittent fasting since high school and have gained lean muscle mass and virtually zero fat. Throughout this period, I’ve never eaten breakfast, mostly skip lunch, eat the majority of my food in a single meal, have built an impressive physique, gotten stronger, and have never lost my six-pack abs. With deep keto-adaptation and proper nutrient timing, I’m able to build muscle at linear progression. The Metabolic Autophagy Protocol will teach you the same principles.
Chapter IX
Protein Absorption and Anabolism
“Part of my daily regime is my glucosamine and,
of course, a multitude of multivitamins.
Branched-chain amino acids, glutamine, of course, protein.
I have one protein shake a day, and that is immediately after my training.”
Dwayne ‘The Rock’ Johnson
We’ve been talking about protein for quite a while now and it’s time to close the circle on this essential macronutrient. Although it might seem that fitness people and nutritionists over-emphasize the importance of protein, it really is that important. In fact, for body composition as well as longevity it’s probably quintessential. That’s why we’re getting into such detail.
To maintain a certain amount of body weight and lean tissue, you have to support that with adequate protein intake. If you were to eat less protein than your body currently needs or if you were to fast over the course of a long period of time, you’ll gradually lose some bodyweight because of the lack of amino acid building blocks and lower levels of protein synthesis.
We mentioned earlier that the process of gluconeogenesis is driven by demand not supply. In the case of not getting enough protein or glucose without being in ketosis, the demand is there and it’s quite huge.
If the brain isn’t using ketones or the liver hasn’t even produced them, then the only option for the body to maintain its energy homeostasis is to sacrifice its muscle tissue and cellular debris by converting them into glucose. The reason is that muscle is very expensive to keep around during energy crises because it requires a lot more calories to sustain. When protein requirements are met and ketones are accepted, this process is circumvented and the body will use body fat stores instead.
Protein is the only macronutrient that can’t be stored inside the body long-term.
Carbohydrates can be stored as liver and muscle glycogen (100-500 grams). Extra carbs will be burnt off as energy or converted into triglycerides and get stored as body fat.
Fat and extra carb can be stored in an infinite amount as body fat in the adipose tissue. You can gain as much adipose tissue as you can possibly consume from too many calories.
Protein intake will be used for elevating muscle protein synthesis and activating mTOR which will help to maintain your current lean muscle mass. To activate these pathways, you need only a certain amount of protein and more won’t have a dose-increasing effect.
You can't really store protein inside the body beyond a certain necessary limit. To store protein it has to be converted into glucose through gluconeogenesis first. That glucose will then either be burnt off as energy or if you’ve already met your daily caloric needs, stored as fat.
The notion that protein can be converted into glucose is a double-edged sword. At times of over-consuming protein, it’ll be simply turned into another fuel substrate that the body will then use based on its requirements. However, when you’re not getting enough protein on a consistent basis and you’re also at a caloric deficit, that same process of gluconeogenesis may turn to your lean muscle tissue and convert that into glucose.
Like I just said, gluconeogenesis is driven by demand, not supply, which is why you want to minimize the demand for glucose by becoming more keto-adapted and staying in ketosis while fasting.
In the short term, an influx of increased protein supply won’t trigger gluconeogenesis of your own muscle tissue because there is no demand there. The body will have met its need for amino acids and thus doesn’t require additional glucose. Temporary protein stores fluctuate throughout the day and they’re connected to the feeding and fasting cycles[410].
How Much Protein Does Your Body Need
The amount of protein you need per day depends on many things and people need different amounts.
The more lean muscle mass you have, the more protein you need to sustain that amount of muscle. Higher bodyweight requires more building blocks just because of having more mass. However, for optimal health and body composition, you’d want to focus on your lean muscle mass. The idea is to lose the fat and maintain the muscle not feed the fat with extra calories from unnecessary protein.
Being more active in general increases your protein demands because physical activity damages the muscle cells to a certain extent[411]. If you do resistance training, you need more protein to support that training with enough protein synthesis and mTOR activation.
If you do primarily endurance training, you need slightly less protein because endurance training doesn’t break down that much muscle tissue as resistance training does. Even if it does, the purpose of endurance training isn’t to build muscles so the desired intake of protein wouldn’t be higher either.
As you age your ability to maintain skeletal muscle decrease and thus you need more protein as well.
The recommended dietary allowance (RDA) for protein is 0.36g/lbs of bodyweight which for an average indi
vidual weighing between 150-180 pounds would be 55-70 grams of protein per day[412]. However, this is not ideal for the majority of the population and most people actually need more, especially if you’re exercising.
In general, the optimal amount of protein tends to be somewhere between 0.7-1.0 g/lbs or 1.5-2.0 g/kgs of lean body mass (LBM), which for the same average individual weighing between 150-180 pounds would be 110-160 grams of protein at a minimum. There are no seeming benefits to eating more than 0.8 g/lbs of LBM, even when trying to build muscle. You definitely don’t need to be eating above 1.0g/lbs of LBM as you’ll simply waste that protein.
How Much Protein Can Your Body Absorb in One Sitting?
One of the additional reasons why it’s thought you can’t build muscle with intermittent fasting is that you won’t absorb enough protein during the 24-hour period. To keep MPS active you have to spike it up with frequent protein ingestions because there’s only a limited amount of protein your body can absorb in one meal. Is that true?
When you digest protein, it gets broken down into amino acids that will be transported into the bloodstream to be used as building blocks. There are a limited amount of transporter cells and receptors in the small intestine which restricts how many amino acids can be moved into the blood. Hence the theory that your body can only absorb a certain amount of protein in one meal.
Certain proteins are absorbed faster than others which allows the amino acids to be used more quickly as well. However, there are many other factors that determine protein absorption such as the pH levels of the gut, the permeability of the intestinal lining, protein sensitivity, and the presence of hormones related to gastric emptying[413].