Stop it with the straw man arguments already!
No one has said anything about kidneys being HARMED by high protein intakes. In fact, I don't think kidneys can be harmed by protein unless you get whacked in the lower back by a 15 kilo bulk bag. We're talking about STRESS, meaning kidney function is pushed closer to (or past) its limits. Then you do have all sorts of harm happening because of too much waste product in the blood.
If you thought stressing the kidney wouldn???t cause harm, you wouldn't have raised an alarm. Thus, I raised no straw man with you, okay? So relax. I misunderstood you - I thought you meant the stress to the kidney was harm to the kidney. Am I to understand you actually mean stress to the kidney causes harm to the rest of the body, is that it? I'd just like to be clear before I continue to argue; I'm not fond of a moving target.
Fact: 16% of Americans over the age of 20 have some degree of chronic kidney disease.
What proportion of these are fit, healthy athletes? It's a valid question - healthy athletes are able to handle stresses that obese, sedentary people might not.
Fact: Blood tests of urea/nitrogen or creatinine won't show abnormal levels until you've lost about 60% of your kidney function.
Look at some of mine sometime. The day after a workout, or a dose of creatine, and I've got flags on my bloodwork for creatinine - but normal GFR. Follow-up tests show normal creatinine - and still show normal GFR.
Fact: Higher protein intake results in higher blood levels of metabolites which the kidneys must filter.
So does a heavy workout.
All I'm saying is there's got to be a better way of recommending protein intake that is sufficient but not too much overkill, because overkill is bad for the wallet, and might overload one's kidneys.
High protein intake is satiating, and tends to help in the fight against obesity. Very good for healthy bones, too.
And while it's generally not a problem, I'd rather avoid beginners rolling dice, considering it's a 1 in 6 chance that they will have less than perfect kidneys.
based on your 16% above? Doubtful. You're implying the problem is genetic, not induced. I'd argue elevated blood glucose are behind a great deal of this figure.
Not to mention that acetaminophen and ibuprofen use are associated with kidney dysfunction, and some weightlifters pop those things like candy (unless they've read up on their effects on protein synthesis, that is). Plus any other supplements they're taking may have an impact on how much 'work' is required of the kidneys.
A lot of people pop analgesics like candy. I did, when I was fat and got headaches all the time. I don???t get 'em now that I eat a high protein diet. Go figure.
Yeah, women are about 35% muscle and 25% fat on average, not to mention generally smaller, and certainly don't hypertrophy like men. Definitely a whole 'nother ball game, formula-wise.
Our appetites are also more strongly regulated by CCK, which is strongly promoted by??? wait for it??? protein!
Also, I assure you I am NEVER 25% bodyfat. The fattest I get is 19%, maybe 20% at the end of a bulk. Confirmed by DEXA, to save you from asking. I could NOT manage this on a low protein diet.
I guess my sidetrack question is: Is it worth bothering to come up with a more accurate formula (or chart) that applies to a broader range of individuals (of both sexes) for recommending protein intake? Most of the gram per pound advice I've seen seems geared towards guys packing lots of muscle that needs to be maintained plus account for growth, not weak guys just starting out (which I think is probably half the readership, and maybe more considering experienced lifters wouldn't be looking for that information). Personally, I think there's a better way, I just don't know what all would need to be taken into account.
I think a gram per pound lean mass is a pretty reasonable starting point for most folks, actually.
I mean, look consider maintenance caloric intake is likely to be about 13 - 15 times their bodyweight in pounds. I'll attach this to a 178 lb man by means of an illustration. Suppose he's carrying 10% bodyfat. His lean mass is about 150 lbs, right?
So, according to the various "rules of thumb" bandied around these parts, his baseline diet should be:
Protein: at least 1g/lb lean mass (160g, providing 640 calories)
Fat: at least 0.5g/lb lean mass (80g, providing 720 calories )
Calories: 15 x bodyweight (rounding down to be safe, about 2600 calories)
This leaves room for 1200 calories, which could come from carbohydrate, fat in excess of 80g, protein in excess of 160g or any combination of the three. If we leave it at the roughly 300g carbohydrate, buddy's diet turns into something that looks like this: (somebody, check the old woman's math, okay?)
Baseline diet for bodyweight 178 lbs, 10% bodyfat, 160 lbs lean mass
Calories: 2600
Fat: 80g; 720 calories; about 30% of caloric intake
Protein: 160g; 640 calories; about 25% of caloric intake
Carbohydrate: 310g; 1240 calories; about 45% of caloric intake
Nothing here is setting off any loud flags of concern regarding protein intake. Not to me, anyway. I'm not a fan of percentage based dietary approaches, but even looking at those, nothing here suggests this is a high protein diet - protein in this case makes up the lowest proportion of dietary intake.
Even if buddy found his recovery was better and his energy levels and appetite improved when he increased his protein to just shy of 1.5g/lb lean mass and left fats alone, he still won't be floating in a sea of kidney death:
Calories: 2600
Fat: 80g; 720 calories; about 30% of caloric intake
Protein: 235g; 940 calories; about 35% of caloric intake
Carbohydrate: 235g; 940 calories; about 35% of caloric intake
Now listen, I'm generally in agreement here that the importance of protein intake is monstrously overemphasized amongst those looking to pack on size, okay? Invariably it is too satiating; these guys leaning on extra protein find themselves "hardgainers" because they can't eat it all and they need to eat more of the foods that make getting in the extra calories easier.
I only wish to point out that for one, there are other considerations than simply promoting muscle gain, and for another, the protein intake most folks in physical culture
actually consume are likely well within a range that will do nothing but at best promote health, satiety and recovery - and at worst metabolize as somewhat expensive carbohydrate.
