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Protein Intake
Casey Butt: Most credible scientific research that's been done has concluded that hard training bodybuilders and strength athletes need up to 1.76 to 1.8 grams per kilogram of bodyweight per day (g/kg-bw/day) as an optimal protein intake, on a long-term basis. At the same time, it's been found that 1.41 g/kg-bw/day is required to achieve neutral nitrogen balance in strength training individuals. So the research-supported optimal amount of protein comes out somewhere between 0.64 to 0.82 grams per pound of bodyweight per day (g/lb-bw/day). Considering that the average person is about 15% body fat, it's roughly between 0.75 to 0.96 grams per pound of lean body mass (g/lb-lbm/day). To cover the bases, I'd tend to err on the high side of that and aim for 0.96 g/lb-lbm/day - so 1 gram per pound of lean body mass per day is a nice round number to work with.
When protein intake goes above that, the body will increase it's protein oxidation rate and will convert the additional protein into glucose and possibly then body fat (if calories are above maintenance). So if a bodybuilder habitually consumes too much protein it won't be forced into the muscles causing "extra" growth, it will simply be converted and eliminated by the liver and kidneys. In the end, the muscles won't see any more amino acids if a person eats 10 g/lb-lbm/day than if he eats 1 g/lb-lbm/day because the body will simply "deal" with the extra amount. In fact, it appears that under such high protein intakes a person is actually more likely to have a negative nitrogen balance than if he just ate less protein.
However, there are a few other downsides to such a high protein intake. For one, if the body up regulates enzymes that are responsible for protein oxidation, then you will always need that high protein intake to break even. In a sense, your body has become a protein burner, and if you don't take in a huge amount of protein day-in-day-out, then you'll slip into a negative nitrogen balance every time you let your protein intake drop for a few hours. You're not getting anything out of it, but you're now forcing yourself to habitually need a high protein intake or you'll go catabolic. Another significant downside is that high protein intakes have been shown to lower testosterone levels - obviously something of critical importance to avoid for a natural bodybuilder.
But just as the body needs time to adapt to a sudden dramatic increase in calories, protein intake is the same. Your body won't become a raging protein-burning furnace just because you had a high protein meal. If so, a steak would set you off. Similarly, if you go a day or so with low protein intake, your body won't lose all its muscle - luckily the liver acts as a buffer, has a higher protein turnover rate, and absorbs a portion of daily protein intake fluctuations.
At the same time, studies into the phenomenon of "catch-up growth" in underfed animals suggest that the enzymes responsible for increased protein oxidation seem to take two-to-three days of high protein intake in order to be up regulated to the point where they catch up with the increased protein. Until that time the increased amino acid levels in the blood will promote muscle protein anabolism. During such periods it has been shown that protein intakes as high as 3.3 g/kg-bw/day (also stated as 1.5 g/lb-bw/day or 1.76 g/lb-lbm/day) can promote maximum growth. This has been suggested as one of the factors responsible for the rapid increase of lean body mass in the early stages of protein and calorie over-feeding during "catch-up growth". After three days, however, the body simply gets better at eliminating the extra protein to the point where you're no farther ahead.
Similarly, if you suddenly start consuming less protein, it will take several days for the urea-cycle enzymes to be down-regulated and the body to lower its rate of protein degradation. The body will also get more efficient at "recycling" amino acids by salvaging them from the urea cycle. Before that happens, protein synthesis will be lowered in the muscle, while degradation continues at its normal pace - you'll won't grow and you'll probably atrophy somewhat. When the urea-cycle and urea-salvage pathways get up to speed, however, the situation will normalize as the body becomes more efficient at how it handles its amino acid reserves.
As was discussed earlier, the muscles are only in an anabolic state for 36-48 hours following training (incidentally, muscle protein synthesis appears to peak at about 24 hours after the training session). So, accounting for digestion transit times, I recommend that bodybuilders consume most of their dietary protein in the several hours before training to roughly 22 hours afterwards. Between 36-48 hours after training a trainee doesn't need any higher protein intake than a sedentary individual - which is about 0.80 g/kg-bw/day or roughly 0.43 g/lb-lbm/day.
My advice for natural bodybuilders is to either keep protein intake fixed at roughly 1 g/lb-lbm/day or, if they wish to take advantage of any potential growth benefits of short-term protein over-feeding, take in up to 1.76 g/lb-lbm/day in the 2 hours before and 22 hours after heavy training sessions. The day after that, protein intake should be lowered back down to 1 g/lb-lbm/day. To avoid adaptation to habitually high protein intakes, I then recommend at least one day of lowered protein intake of roughly 0.43 g/lb-lbm/day at least 48 hours after a heavy training session.
This type of protein cycling is most practical on full body routines. For instance, if you train Monday/Wednesday/Friday, with Monday heavy, Wednesday light and Friday medium you could eat high protein on Monday (1.76 g/lb-lbm/day starting about 2 hours before the heavy workout and continuing for the next 24 hours), then on Tuesday, Wednesday and Thursday you'd go back to taking in 0.96~1.0 g/lb-lbm/day. On Friday (medium day) you'd up it to 1.76 g/lb-lbm/day again (similar to Monday). On Saturday and Sunday, in order to stave off adaptation to high protein intakes during the week, you'd lower protein intake to 0.43 g/lb-lbm/day - this could also serve as carb-up days for Monday's heavy workout and the rest of the week.
At the more advanced stages, when training is arranged as several heavy days in a row, followed by several lighter days to allow for nervous system recuperation, then protein cycles could become deeper, with up to three days of high protein intake followed by three days of lowered intake.
This is all assuming that calorie intake is sufficient. When calories go down, protein requirements go up. But there is very little scientific research available concerning protein requirements of bodybuilders in calorie deficits. In any case, experience and common sense would have to be the discriminating factor - as it should be in all training and nutrition related considerations.
I've probably made it sound overly complicated above, but it really doesn't have to be - the simplified version is that your body isn't stupid, it likes to preserve homeostasis, and it needs more protein in the day or so following heavy training. Eat more protein after you train hard and then eat less around the days that you're not training heavy so your body doesn't adapt to constantly excessively high protein levels.
bron: An Interview with Casey Butt, Part 2 | Muscle & Strength
Casey Butt: Most credible scientific research that's been done has concluded that hard training bodybuilders and strength athletes need up to 1.76 to 1.8 grams per kilogram of bodyweight per day (g/kg-bw/day) as an optimal protein intake, on a long-term basis. At the same time, it's been found that 1.41 g/kg-bw/day is required to achieve neutral nitrogen balance in strength training individuals. So the research-supported optimal amount of protein comes out somewhere between 0.64 to 0.82 grams per pound of bodyweight per day (g/lb-bw/day). Considering that the average person is about 15% body fat, it's roughly between 0.75 to 0.96 grams per pound of lean body mass (g/lb-lbm/day). To cover the bases, I'd tend to err on the high side of that and aim for 0.96 g/lb-lbm/day - so 1 gram per pound of lean body mass per day is a nice round number to work with.
When protein intake goes above that, the body will increase it's protein oxidation rate and will convert the additional protein into glucose and possibly then body fat (if calories are above maintenance). So if a bodybuilder habitually consumes too much protein it won't be forced into the muscles causing "extra" growth, it will simply be converted and eliminated by the liver and kidneys. In the end, the muscles won't see any more amino acids if a person eats 10 g/lb-lbm/day than if he eats 1 g/lb-lbm/day because the body will simply "deal" with the extra amount. In fact, it appears that under such high protein intakes a person is actually more likely to have a negative nitrogen balance than if he just ate less protein.
However, there are a few other downsides to such a high protein intake. For one, if the body up regulates enzymes that are responsible for protein oxidation, then you will always need that high protein intake to break even. In a sense, your body has become a protein burner, and if you don't take in a huge amount of protein day-in-day-out, then you'll slip into a negative nitrogen balance every time you let your protein intake drop for a few hours. You're not getting anything out of it, but you're now forcing yourself to habitually need a high protein intake or you'll go catabolic. Another significant downside is that high protein intakes have been shown to lower testosterone levels - obviously something of critical importance to avoid for a natural bodybuilder.
But just as the body needs time to adapt to a sudden dramatic increase in calories, protein intake is the same. Your body won't become a raging protein-burning furnace just because you had a high protein meal. If so, a steak would set you off. Similarly, if you go a day or so with low protein intake, your body won't lose all its muscle - luckily the liver acts as a buffer, has a higher protein turnover rate, and absorbs a portion of daily protein intake fluctuations.
At the same time, studies into the phenomenon of "catch-up growth" in underfed animals suggest that the enzymes responsible for increased protein oxidation seem to take two-to-three days of high protein intake in order to be up regulated to the point where they catch up with the increased protein. Until that time the increased amino acid levels in the blood will promote muscle protein anabolism. During such periods it has been shown that protein intakes as high as 3.3 g/kg-bw/day (also stated as 1.5 g/lb-bw/day or 1.76 g/lb-lbm/day) can promote maximum growth. This has been suggested as one of the factors responsible for the rapid increase of lean body mass in the early stages of protein and calorie over-feeding during "catch-up growth". After three days, however, the body simply gets better at eliminating the extra protein to the point where you're no farther ahead.
Similarly, if you suddenly start consuming less protein, it will take several days for the urea-cycle enzymes to be down-regulated and the body to lower its rate of protein degradation. The body will also get more efficient at "recycling" amino acids by salvaging them from the urea cycle. Before that happens, protein synthesis will be lowered in the muscle, while degradation continues at its normal pace - you'll won't grow and you'll probably atrophy somewhat. When the urea-cycle and urea-salvage pathways get up to speed, however, the situation will normalize as the body becomes more efficient at how it handles its amino acid reserves.
As was discussed earlier, the muscles are only in an anabolic state for 36-48 hours following training (incidentally, muscle protein synthesis appears to peak at about 24 hours after the training session). So, accounting for digestion transit times, I recommend that bodybuilders consume most of their dietary protein in the several hours before training to roughly 22 hours afterwards. Between 36-48 hours after training a trainee doesn't need any higher protein intake than a sedentary individual - which is about 0.80 g/kg-bw/day or roughly 0.43 g/lb-lbm/day.
My advice for natural bodybuilders is to either keep protein intake fixed at roughly 1 g/lb-lbm/day or, if they wish to take advantage of any potential growth benefits of short-term protein over-feeding, take in up to 1.76 g/lb-lbm/day in the 2 hours before and 22 hours after heavy training sessions. The day after that, protein intake should be lowered back down to 1 g/lb-lbm/day. To avoid adaptation to habitually high protein intakes, I then recommend at least one day of lowered protein intake of roughly 0.43 g/lb-lbm/day at least 48 hours after a heavy training session.
This type of protein cycling is most practical on full body routines. For instance, if you train Monday/Wednesday/Friday, with Monday heavy, Wednesday light and Friday medium you could eat high protein on Monday (1.76 g/lb-lbm/day starting about 2 hours before the heavy workout and continuing for the next 24 hours), then on Tuesday, Wednesday and Thursday you'd go back to taking in 0.96~1.0 g/lb-lbm/day. On Friday (medium day) you'd up it to 1.76 g/lb-lbm/day again (similar to Monday). On Saturday and Sunday, in order to stave off adaptation to high protein intakes during the week, you'd lower protein intake to 0.43 g/lb-lbm/day - this could also serve as carb-up days for Monday's heavy workout and the rest of the week.
At the more advanced stages, when training is arranged as several heavy days in a row, followed by several lighter days to allow for nervous system recuperation, then protein cycles could become deeper, with up to three days of high protein intake followed by three days of lowered intake.
This is all assuming that calorie intake is sufficient. When calories go down, protein requirements go up. But there is very little scientific research available concerning protein requirements of bodybuilders in calorie deficits. In any case, experience and common sense would have to be the discriminating factor - as it should be in all training and nutrition related considerations.
I've probably made it sound overly complicated above, but it really doesn't have to be - the simplified version is that your body isn't stupid, it likes to preserve homeostasis, and it needs more protein in the day or so following heavy training. Eat more protein after you train hard and then eat less around the days that you're not training heavy so your body doesn't adapt to constantly excessively high protein levels.
bron: An Interview with Casey Butt, Part 2 | Muscle & Strength
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