I used the 1.5 g per pound of BW approximation for my contest prep and had great results and retained almost all my strength in a caloric deficit over several months. This old argument about 1.5g of protein kg vs lbs, and any excess being a waste, has been addressed and argued many times. In short, I don't listen to what my fat health nutrition teacher regurgitated (taught) but rather what I have seen in conjunction with articles I have read and the experiences of others that I respect such as these pasted below.
c/p by Martin Berkhan:
Whenever you hear something really crazy you need to ask yourself if it makes sense from an evolutionary perspective. It's a great way to quickly determine if something may be valid or if it's more likely a steaming pile of horse****. This myth is a great example of the latter. Do you think we would be here today if our bodies could only make use of 30 grams of protein per meal?
The simple truth is that more protein just takes a longer time to digest and be utilized. For some concrete numbers, digestion of a standard meal is still incomplete after five hours. Amino acids are still being released into your bloodstream and absorbed into muscles. You are still "anabolic." This is a fairly standard "Average Joe"-meal: 600 kcal, 75 g carbs, 37 g protein and 17 g fat. Best of all? This was after eating pizza, a refined food that should be quickly absorbed relatively speaking.
Think about this for a second. How long do you think a big steak, with double the protein intake of the above example, and a big pile of veggies would last you? More than 10 hours, that's for sure. Meal composition plays an important role in absorption speed, especially when it comes to amino acids. Type of protein, fiber, carbohydrates and prior meals eaten all affect how long you'll have amino acids released and being taken up by tissues after meals.
Origin of the myth:
I think this "30 grams of protein"-nonsense started to circulate after a classic study from 1997 by Boirie and colleagues. "Slow and fast dietary proteins differently modulate postprandial protein accretion" was the first study to quantify the absorption rate of whey and casein protein and gave birth to the concept of fast and slow protein. After that, whey protein came to be known for it's ability to rapidly elevate amino acids in the blood stream and casein for it's ability to create a sustained release of amino acids. Whey was anabolic and casein anti-catabolic.
Given that 30 grams of whey protein was absorbed within 3-4 hours, I guess some people believed that meant 30 grams of protein can only be used in one sitting. Or that you had to eat every 3-4 hours to stay "anabolic." Unfortunately, people missed a few facts that made these findings irrelevant to real-world scenarios. First of all, this study looked at the absorption rate of whey protein in the fasted state. On it's own, and with no meals eaten beforehand, 30 grams of whey protein is absorbed within a mere 3-4 hours. With meals eaten earlier in the day, or if you'd consume a whey shake after a meal, absorption would be much slower.
Second of all, whey protein is the fastest protein of all and digests at 10 g/hour. Casein is much slower; in Boirie's study, the casein protein was still being absorbed when they stopped the experiment 7 hours later. Most whole food proteins are absorbed at a rate of 3-6 grams an hour. Add other macronutrients to that and they'll take longer.
Here's another article that addresses this subject head on by well-renowned Alan Aragon. Invalid Link Removed
References:
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-Bilsborough S, Mann N. A review of issues of dietary protein intake in humans. Int J Sport Nutr Exerc Metab. 2006 Apr;16(2):129-52.
-Stote KS, et al. A controlled trial of reduced meal frequency without caloric restriction in healthy, normal-weight, middle-aged adults. Am J Clin Nutr. 2007 Apr;85(4):981-8.
another c/p:
consider all of this "The body can only use X grams per Y" as a lot of nonsense. First and foremost, it makes no evolutionary sense (how I've been looking at a lot of physiological processes lately). That is, our ancestors did not eat protein in small amounts throughout the day. Yet, anthropological studies show that they had more muscle and bone mass than most of us. Rather, they were more likely to eat a ton of protein after a kill, and whatever amount they got from vegetables and such the rest of the time. Massive protein intakes at once were more likely the norm during 99% of our evolution than not. This means that our guts evolved to handle it. In addition, when you start looking at digestion and such, you see exactly that: even with massive protein loads (I vaguely recall they've looked at like 1.5 g/kg of beef all at once), digestion still stays very high (on average 90-95% for animal proteins meaning you're losing at most 10 grams of protein/100 grams ingested). The body can digest/absorb pretty much anything you throw at it. You won’t be pooping protein if you eat 35 grams at a sitting, is what I'm saying.
Now, a slightly separate issue might be one of how much protein (amino acids really) the liver can handle at once. If the recent studies on whey vs. casein have pointed anything out, it's that flooding the liver with amino acids at a high rate leads to increased amino acid oxidation (burning) in the liver. I suppose it's conceivable that high protein intakes at any given meal could be having this effect. I suspect it depends on the source of the protein (whole food which digests slowly vs. protein powders which digest faster). That is, consuming, say, 50 grams of whey protein at once might lead to more waste (mainly as amino acids oxidized and then converted to urea) than 50 grams of casein or beef. But that's more an issue of speed of digestion than amount per se.
In terms of supporting optimal growth, an interesting discrepancy actually occurs here between the studies on our ancestral diet and the protein needs of athletes, but nobody has an explanation yet. Good studies by Peter Lemon, Mark Tarnopolsky, etc. support a maximum protein requirement for natural lifters of about 1.8 g/kg (a little less than the 1 g/lb that bodybuilders have used for years). But studies of our ancestral diet suggest protein intakes as high as 2.5-3 g/kg. Nobody is quite sure if this protein intake was simply a side effect of the diet our ancestors followed, or if it had some actual benefit.
Finally, I think the whole 30 g/meal (or whatever) thing can't possibly apply to everyone. I mean, at the low end, figure a 210 lb lifter is eating 210 grams of protein per day. If he's limited to 30 grams/meal, that means seven meals minimum per day. Obviously, if there is some limit to protein absorption/assimilation/digestion/utilization (and I don't honestly think that there is) it's going to be related to body mass: a larger individual needs more protein and would be able to utilize protein in larger amounts than a smaller person. Ultimately, my hunch is that the whole '30 grams per meal' (or whatever) thing came from one of two places:
i)Early supplement companies trying to convince lifters why their protein product (containing 30 grams) was better than others. I remember one company pulling a scheme like this, when their product contained like 37 grams of protein, they wrote that 37 grams was the maximum that could be absorbed. When they bumped it to 42 grams of protein per serving, 42 became the magic number. Ah, advertising.
ii)Bodybuilders rationalizing what they had already decided to do. That is, you frequently see bodybuilders and other athletes finding a strategy that works (i.e. eat protein at intervals throughout the day) and then making up physiological rationalizations afterwards. It wouldn't really surprise me if that weren't the case here. Of course, if anybody has a single piece of peer-reviewed research supporting this 30 grams myth (everybody seems to claim to have seen it but nobody seems to ever have it; it's like those friend of a friend stories)