Estimating Protein Requirements with Bloodwork

[Kaladryn]

Blood Urea Nitrogen (BUN) is a blood test on a standard "chem panel" that is considered a marker for kidney function. Normal ranges are generally 6 - 20 ng/dL.

When your liver (and kidneys when liver is overloaded) breaks down amino acids into glucose, nitrogenous waste is produced. One of the main functions of the kidneys is to deal with these nitrogenous wastes. First they are turned into ammonia, then uric acid, finally urea (all done by the kidneys). Finally they are concentrated and excreted.

Assuming your kidneys are working well, BUN is a good estimation of how much protein is being broken down. Assuming also that you are well hydrated, a BUN level out of the normal range means you should eat less protein and more carbs. Following this method, I was surprised to find that I don't need very much protein at all: 40g/meal for a heavyweight bodybuilder and I'm STILL pushing 19-21 BUN.

Even if you follow your own guidelines, BUN should be a useful tool for figuring out how much protein to eat.

 

[anabolicscuba]

Thanks for the insightful post. My BUN is always high, ranging from 22-29 every time. My creatinine is always in range though. I guess I should be eating less protein.

 

[Jblack]

Last time I went for blood work I was dehydrated so my BUN levels were I think 24? Doctor had me come back in later the next day and my bun was 18. I used to never even care about anything except for Hematocrit and Cholesterol - now I look at the whole thing.

Thank you for this post...I go for blood work in a few weeks and interested to see how my numbers look.

I work in a hot gym all day (think metroflex) so I really have to pound some water to stay hydrated...

 

[Leggo my Ego]

Thanks for posting Kaladryn. Very informative.

May I ask what your background is? I have read alot of our posts and you seem to be very well read/informed (intelligent with a touch of humor). Anyway, I enjoy and appreciate your posts.

 

[Kaladryn]

Thanks for posting Kaladryn. Very informative.

May I ask what your background is? I have read alot of our posts and you seem to be very well read/informed (intelligent with a touch of humor). Anyway, I enjoy and appreciate your posts.

Thank you, I'm just a trainer/bodybuilder with a background in biochem, never finished. Some of the info above I'm pulling from a class that went very in depth on the kidneys and sodium potassium pumps. Also, for the last 20+ years I have been seeing a really good forward thinking semi holistic MD who has taught me an immense amount.

 

[Leggo my Ego]

Thank you, I'm just a trainer/bodybuilder with a background in biochem, never finished. Some of the info above I'm pulling from a class that went very in depth on the kidneys and sodium potassium pumps. Also, for the last 20+ years I have been seeing a really good forward thinking semi holistic MD who has taught me an immense amount.

Cool, man. thank you for sharing

 

[tornquad]

based on Bun levels if I was 14 would you suggest less protein and more carbs also does eating more potassium base foods greens and starches pump out excess sodium .

 

[KillerStack]

Did you guys see Farah's frankly ridiculous
IG video where he said one can only utilize 30grams per
meal? He didn't even qualify it by saying it's individual
depending on one's size etc, which he later backtracked on and said, sure, Kai may eat 60-70-80-90g per meal.

Milos did some rebuttal video about his 400-450g a day for 30 years and how every time he tried lowering it he always lost size. Then he referenced Nasser who suddenly increased to 600g after talking to Milos and promptly put on 25lbs of stage weight. He didn't credit the insulin this time Lol. Nasser used to BS about only eating 100grams in the off-seasons as I recall.

Patrick Tuor has some post contest cleanse type phase for his athletes which is 1g per kilo, or 100 grams for a 220lbs guy. Lots of carbs instead.

 

[KillerStack]

Lyle McDonald wrote a good article about the problems with relying on MPS rates following feedings to arrive at optimal daily requirements.

**broken link removed**

 

[Kaladryn]

based on Bun levels if I was 14 would you suggest less protein and more carbs also does eating more potassium base foods greens and starches pump out excess sodium .

Wow this is an old thread, I forgot I wrote this. I think a 14 is pretty low I would increase protein intake but it largely depends on your goals.

Did you guys see Farah's frankly ridiculous
IG video where he said one can only utilize 30grams per
meal? He didn't even qualify it by saying it's individual
depending on one's size etc, which he later backtracked on and said, sure, Kai may eat 60-70-80-90g per meal.

Milos did some rebuttal video about his 400-450g a day for 30 years and how every time he tried lowering it he always lost size. Then he referenced Nasser who suddenly increased to 600g after talking to Milos and promptly put on 25lbs of stage weight. He didn't credit the insulin this time Lol. Nasser used to BS about only eating 100grams in the off-seasons as I recall.

Patrick Tuor has some post contest cleanse type phase for his athletes which is 1g per kilo, or 100 grams for a 220lbs guy. Lots of carbs instead.

The 30g/meal thing is one of the most classic pieces of broscience of all time. There have been so many investigations into the origins of it, none of which are legit in any way obviously. I think theories like this come from "studies" where they fed people absurd amounts of protein who had otherwise been on low protein diets and ended up not digesting some of it. All the good studies on food absorption involve collecting poop and testing it also btw...

Protein intake is really a matter of preference, how much protein do you want to burn as energy, the body seems to be happy doing it. If you are carb sensitive and don't want to eat more calories from fat, you might want to burn more calories from protein.

BTW, protein not burned as energy is calorie free, any energy it has becomes potential energy as part of the repaired tissue. It also takes additional energy to create this tissue.

Lyle McDonald wrote a good article about the problems with relying on MPS rates following feedings to arrive at optimal daily requirements.

**broken link removed**

MPS rates aren't related in a calorie surplus, we are just talking about dietary protein being burned as energy, not muscle protein breakdown.

Good book

(edit): BTW I like a higher percentage of total calories from protein when dieting and my BUN goes up into the mid to high 20s when dieting hard.

 

[IronLion2]

I use things like this for myself and some of my "clients." My only rebuttal is if were seeing an in range BUN:Cr ratio than anything below 40 is likely fine, in my unprofessional opinion . Context is always king.

 

[buck]

Wow this is an old thread, I forgot I wrote this. I think a 14 is pretty low I would increase protein intake but it largely depends on your goals.



The 30g/meal thing is one of the most classic pieces of broscience of all time. There have been so many investigations into the origins of it, none of which are legit in any way obviously. I think theories like this come from "studies" where they fed people absurd amounts of protein who had otherwise been on low protein diets and ended up not digesting some of it. All the good studies on food absorption involve collecting poop and testing it also btw...

Protein intake is really a matter of preference, how much protein do you want to burn as energy, the body seems to be happy doing it. If you are carb sensitive and don't want to eat more calories from fat, you might want to burn more calories from protein.

BTW, protein not burned as energy is calorie free, any energy it has becomes potential energy as part of the repaired tissue. It also takes additional energy to create this tissue.



MPS rates aren't related in a calorie surplus, we are just talking about dietary protein being burned as energy, not muscle protein breakdown.

Good book

(edit): BTW I like a higher percentage of total calories from protein when dieting and my BUN goes up into the mid to high 20s when dieting hard.

I saw Lou Ferrigno claim 30gr/meal in an article back in the early 70's and I always figured that is where it started.

 

[Kaladryn]

I use things like this for myself and some of my "clients." My only rebuttal is if were seeing an in range BUN:Cr ratio than anything below 40 is likely fine, in my unprofessional opinion . Context is always king.

I agree I don't really think higher levels are bad but I do think too much excess protein means you can't eat as many calories from carbs and/or fats, both of which I consider anabolic to a certain degree (to quote Chris Aceto).