Bill Phillips: Let's talk about something you mentioned in our last interview—cycling protein intake. How does this work, and why would someone want to do this? I was under the impression that you had to consume a high-protein diet every day to gain muscle. It sounds like a wild theory to be honest.

Torbjorn Akerfeldt: I realize that by introducing the concept of protein cycling, I might cause some of your readers to say, "That Swedish guy with the unpronounceable name has finally gone nuts..." I say this because I've found that bodybuilders hold three things sacred: heavy squats, steroids—or creatine for drug-free bodybuilders—and a high protein intake. As long as you don't touch these dogmas, many bodybuilders will listen and be prepared to do some of the most outrageous, unscientific, and often dangerous things, in an effort to become bigger and stronger. However, I have to challenge one of these fundamentals: namely, the high protein intake. I know some of your readers, after reviewing even this much of the text, will flip to the next article. I warn them that this is a big mistake. By "hearing me out," I promise they'll learn something new about protein metabolism and muscle growth that may change the way they view protein intake forever, allowing them to reach a new standard of muscle growth and fat loss.

BP: Should we cycle protein like calories—going two weeks on a high-protein diet and two weeks on a low-protein diet?

TA: No. I need to emphasize that my theory involves reducing protein intake only for a few days at a time. In order to understand why this is important—why it could allow bodybuilders to get better results from their workouts—I need to explain some of the basics about protein and its biochemistry, so please bear with me. I believe that if more bodybuilders understood the contemporary science behind the metabolic processes of muscle growth and fat loss, they would be able to spot a flawed theory before they had put a lot of their blood, sweat, and tears—not to mention money—into it. As I've explained in my previous interviews, it is important to understand that we all react and adapt to dietary changes; our bodies are constantly trying to outsmart us, you might say. I see this not only in the gym but also when reviewing statistics from scientific studies on nutrition. The body is amazing.

BP: What is it about protein metabolism that I, and other bodybuilders, really need to know?

TA: Let me start with the basics—as you know, protein is made up of "building blocks" called amino acids, which basically consist of one, two, or three nitrogen atoms bound together with a carbon skeleton. Amino acids can be attached to each other by peptide bonds, thus forming long chains of interconnected amino acids. These chains or peptides are named after the number of amino acids they contain; hence, they are called dipeptides, tripeptides, etc. If there are more than 10 amino acids present, the term polypeptide is used, and if the number exceeds 50, they are normally referred to simply as "proteins." These proteins have different properties, depending on the sequence of the amino acids which form them. Actually, more than 100 amino acids exist in nature, but only 20 of them can be used to build proteins in the human body.
Examples of amino acids which can't be part of the protein structure include gamma-aminobutyric acid [GABA] and L-dopa, both of which are known to be used and misused by bodybuilders. The body also has the ability to change the structure of certain amino acids that have already been incorporated into proteins, thus forming new amino acids such as hydroxyproline [which exists in connective tissue] and 3-methylhistidine [which exists in muscle].
Furthermore, the body can make non-protein amino acids, such as ornithine, and the nonessential, or dispensable, amino acids, which are necessary to synthesize proteins. The reason the body has developed this dynamic ability to create new amino acids is to fulfill the precise needs of the body despite protein intakes that vary widely in quality and quantity. However, the body cannot manufacture all amino acids—certain ones just cannot be synthesized. These are called essential, or indispensable, amino acids. They must consequently be provided in the foods you eat.

BP: I follow you—we covered these things in my Sports Supplement Review^®, and I agree this basic science of protein should be understood by bodybuilders. What do you think is important to know about protein metabolism?

TA: Protein metabolism is very complex and is an area of science we're only beginning to really understand. However, there are some things which are relevant to my theory which bodybuilders should have a handle on. Basically, what you need to know is that all the amino acids we ingest in the form of proteins are broken down to free amino acids and used, for example, to build new proteins according to the metabolic state that exists at that moment in the body. What the body does with the various proteins once it disassembles them into these free amino acids depends on your previous food intake, your physical activity, your hormonal status, and a number of other things. These new proteins, depending on the type [e.g., muscle, gut, and liver proteins], have different rates of turnover. Since this area is quite complex, I have created an overview chart [below] that will hopefully offer some assistance. I think this chart includes some important information, especially for Muscle Media readers with a scientific background who are eager to learn more about protein metabolism. The numbers were chosen with a 200-lb bodybuilder in mind.

BP: I think so. What you're saying is if I consume 400 grams of protein every day, initially this might cause an anabolic effect, but eventually, if I keep doing this, I'll need 400 grams of protein a day just to maintain my current level of muscle mass. Is this what you're saying?

TA: Exactly. The body adapts by up-regulating enzymes and systems that break down amino acids.

BP: So how much protein should we consume?

TA: At first glance, a diet dominated by protein seems to be the logical choice for every bodybuilder. After all, there are reasons this macronutrient is called protein—it's Greek for "of prime importance."
In addition to carbon, hydrogen, and oxygen, protein contains nitrogen and some sulfur, which make it different from fats and carbohydrates.
Protein can be used to create carbohydrates, and with some difficulties, it can be converted to fat, but carbohydrates and fats can never be turned into proteins unless nitrogen is present, and as we've already discussed, nitrogen comes only from protein.
Strangely enough, the current United States Recommended Daily Allowance (RDA) does not include an additional amount of protein for those who regularly engage in physical exercise.¹⁵ Several recent studies, however, indicate that dietary protein intake in excess of the current RDA [.8 g/kgBW/d—that's only 72 grams a day for a 200-lb bodybuilder] is likely needed for optimal muscle growth. For example, in one study, heavy resistance-training young adult men consuming 3.3 g/kgBW/d [which is about 300 grams per day for a 200-lb guy] versus 1.3 [about 120 grams a day] gained 2.2 more pounds of bodyweight in just 14 days⁴!
Another study found protein synthesis in strength-training subjects went up when protein intake was increased from .9 to 2.4 g/kgBW/d.²¹ These studies concluded that 2.4 and 3.3 g/kgBW/d, respectively, were in excess of the amount needed for optimal muscle growth. For example, in the study using 3.3 g/kgBW/d, the "safety valve," called oxidation, increased by 159%.⁴ These and other researchers now think that the "optimal" protein intake for strength-training athletes might be 1.8 g/kgBW/d^11,21 [about 160 grams of protein for a 200-lb lifter].
I strongly disagree with this theory. I do not believe the subjects who put on an additional 2.2 lbs of mass in 14 days by increasing their protein intake to 3.3 g/kgBW/d⁴ would have been equally successful if they had increased it only to 1.8 g/kgBW/d.

BP: So why would the researchers only recommend 1.8 g/kgBW/d?

TA: I think the answer lies in how we would define the word "optimal." For bodybuilders, it means maximum muscle growth, while for scientists, it means, more or less, the level at which "safety valves" are induced disproportionately to increased protein intake.²⁵ This discrepancy can be explained within the anabolic drive theory, which was developed by a scientist named D.J. Millward, who has developed other interesting theories on muscle growth which we've discussed in earlier parts of this article series.
Dr. Millward believes dietary protein is a key active nutritional regulator. In short, his anabolic drive theory states that "excessive dietary indispensable [essential] amino acids, prior to their oxidation, exert an important transient regulatory influence on growth, development, and protein turnover, through their activation of various hormonal and metabolic responses, which collectively constitute the anabolic drive."¹²
The response he's referring to consists of an increase in anabolic hormones, including thyroid hormone [T₃] which, in small amounts, is anabolic in muscle tissue. The metabolic response is a direct effect of enzymes stimulating protein synthesis and inhibiting protein degradation.
Notice that Millward mentioned this is a transient phenomenon, giving evidence that the anabolic drive theory is very much in line with my protein cycling theory.
Basically, what it all amounts to is that there are pros and cons associated with a high protein intake—the way to get the positive without the negative is to cycle protein intake.

BP: How did you come up with your protein cycling theory?

TA: In this case, I consider a low-protein intake to be equivalent to slightly above the RDA or 1.1 g/kgBW/d [for a 200-lb bodybuilder, that's roughly 100 grams of protein per day]. There really is no true protein malnutrition, as long as you eat enough carbohydrates to keep the "safety valves" closed [carbohydrates inhibit gluconeogenesis and the urea cycle]. Still, 1.1 g/kgBW/d is a small amount compared to what most bodybuilders ingest daily. I know some bodybuilders who regularly consume upwards of 400 or 500 grams of protein a day—they are definitely "protein dependent." Nevertheless, even my low protein intake is enough to maintain muscle mass in the steroid-free bodybuilder.²²
If you take protein cycling to its extreme, you could go on an even lower protein intake—down to as low as 60 grams per day and instead consume high doses of glutamine and HMB. In this situation, as well as during overtraining, glutamine and HMB may be useful as they inhibit protein breakdown. This low intake of protein would prime the enzymes even more for the high-protein days.
I believe that, optimally, protein cycling should prime the enzymes, assuming we're talking about a 200-lb athlete with a single-digit bodyfat percentage who is fluctuating his protein intake between 100 grams on his low-protein days and around 250-300 grams on his high-protein days.

BP: What type of protein do you recommend? Should it be chicken, fish, milk protein, or whey protein?

TA: I believe during the low-protein days, the importance of protein quality is amplified. Whenever you drop protein intake, the amount of glutathione, which is the body's most important antioxidant, drops as well. This may be mitigated by supplementing the diet with ion-exchanged whey protein.¹ Whey protein may also increase the amount of IGF-1, an important anti-catabolic hormone. And, whey proteins have the best amino acid profile, so they minimize the risk of deficiency in individual amino acids. Remember, the lack of one single type of amino acid is sufficient to hamper protein synthesis.

BP: Should a bodybuilder cycle protein during the high-calorie phase?

TA: I don't believe so. My impression is we shouldn't cycle protein intake during the overfeeding phase because we are trying to evoke a burst of anabolic hormones associated with overfeeding.⁵ During the anabolic/bulking phase, there must be a steady oversupply of all macronutrients. A two-week period of medium to high protein intake [approximately 2.5 g/kgBW/d—about 225 grams a day for a 200-lb bodybuilder] will not drive amino acid catabolic enzymes wild. I do not recommend consuming huge—that is, over 300 grams a day—amounts of protein over an extended period of time.

BP: There has been some debate in the scientific community about whether high-protein diets are dangerous. What do you think?

TA: I don't recommend a very high-protein diet nor protein cycling to people with insufficient kidney function [with serum creatinine over 150 micromol/l] since the high-protein days could throw such a person into a "uremic state," which is not only muscle catabolic but also very unhealthy. For people with critical liver dysfunction, a high-protein diet could also become a problem by inducing encephalopathy [brain damage].
For healthy people, however, protein cycling is probably healthier than chronic high protein intakes. I believe some bodybuilders who are consuming these outrageously high protein intakes—over 400 grams per day—underestimate the possible long-term side effects of such nutritional practices. With these super-high-protein diets, the excess protein is partly converted to toxic metabolites, such as homocysteine and ammonia. [You know you're consuming way too much protein when your gym clothes start to stink like ammonia—even after washing them!]
Most scientists I work with believe nowadays a moderately high-protein diet, especially for people who pay close attention to their fluid balance [increased water loss almost always accompanies a high-protein diet] are not at an increased risk for kidney or liver damage. The problem with many bodybuilders is that it's hard to determine if their abnormal liver and kidney parameters are a result of present or prior use of anabolic steroids or if it's due to dietary factors.
Bodybuilders who consume a super-high-protein diet and are convinced they need this much protein probably do! By consuming so much protein day in and day out, their bodies become so efficient at breaking down amino acids that they have turned their metabolic systems into "protein monsters" that devour amino acids before they can be used to build muscle tissue.

BP: Should you cycle carbohydrates and fat, as well as protein?

TA: There is some basis for performing micro-cycles within the Anabolic Burst Cycling System with carbohydrates and fat, but they are quite different; however, there may be important "tricks" for fat loss especially. I hope to review these in a future article, but for now, if someone is following all the recommendations I made in the first three parts of this article, the next step for them—the thing they can do to get even better results, provided they're following all of my instructions with discipline, is to experiment with protein cycling.

BP:If people are on high-protein diets, how can they get their systems back into balance?

TA: I would recommend that anyone who is on a very high-protein diet start cycling protein intake and gradually lower it. Let's say a 200-lb bodybuilder is consuming 400 grams of protein a day. What I would recommend is that for 3 days, he should cut down to 200 grams of protein a day, then go up to 350 grams a day for 3 days, then come down to about 150 grams a day, up to 250 grams a day for 3 days, and so on.

BP: Who should try protein cycling, and why?

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