Protein myth or reality?

Ok, I'm on a mission now. There are many places which state that we [humans] cannot absorb more than 30g of protein in a single serving. I can't seem to find a source for it though.

Does anyone know where this comes from, or anything else about it? I asked my nutritionist and she had heard it, but never seen citations about it either.

Being science-minded, I really want to find the backing of this statement.

WHERE'S DX WHEN I NEED HIM!!!!!

Speaking of which...where is DX? Spring musical in the works, or so?

This is a popular topic...I've not seen a single piece of scientific proof that this is actually the case.   If someone has actual scientific evidence that this is fact, I want to see it!   Until then I don't subscribe to this...and I typically take in 40-50 grams at a time....especially with the malabsorbtion as a factor - I don't take the chance. Cards Fan

I take 40-50 myself, because of malabsorption. As for a total I've heard nutritionists say about 1 gram per kg. of bodyweight per day and others 2 grams/kg and then bodybuilders recommending around 4 grams. I usually shoot for 150-200 grams a day.

I can imagine there being a limit to how fast our bodies can absorb protein.  Could I chug 300g and absorb it all (assuming my body needed it for some reason)?  I doubt that.  But this statement has always looked like a myth to me.  What is "at one time"?  When is the next time?  Can I drink a shake every hour, but not a double every two hours?  If I sip 60g over 45 minutes, is that OK?  My 4'9" ex-girlfriend has the same 30 grams limitation as 6'0" me?  Please.  Maybe this is like the 60g of protein/day trope (wrong for many people, but based on scientific data about average people with average needs).  Or maybe it's just a nice "rule of thumb" based on someone's best guess that got converted into fact. A person with possible kidney problems would be well advised to spread his protein out, and I do my best to spread my liquid protein in an abundance of caution (don't want to waste my money, spread evenly has to be better than all at once to some degree, otherwise I could take 700g and be done for the week).  Ii sometimes double-up (50 grams or so), I would never triple up.  But I'm just pulling these rules out of my arse.

here we go:

Right now, the U.S. Food and Drug Administration recommends that protein make up 10 percent of the total calories you consume every day. Since protein has 4 calories per gram, in a 2,000-calorie diet, that would allow for 50 grams of protein. Meanwhile, the national average consumption of protein is about 90 grams daily. The only people who might have trouble getting enough protein in their diets are some vegetarians who do not eat any animal products, including eggs and milk. However, even they can get enough protein by consuming foods like lentils, tofu, nuts and peas, all of which are high in protein.  Because the body is unable to store it, excess protein is broken down and converted into sugars or fat Because the body is unable to store it, excess protein is broken down and converted into sugars or fatty acids Because the body is unable to store it, excess protein is broken down and converted into sugars or fatty acids Bottom line, of what I have found out, is that excessive Protein convert to sugar then converts to fat.

Good information, but the question of how much protein can one typically absorb per serving, or how many  grams of protein/hour still eludes us.  Plus, if there is actual medical/scientific data to back up the ~30gm/hour absorbtion rate, I would have to assume that this is based off of an individual with normal plumbing...those of us for example with DS or RNY have varying lengths of bypass which most certainly affects the absorbtion rate. One thing I thought about regarding absorbtion...I'm not much of a drinker at all, but on the rare occasion I do have an alcoholic beverage I get the "buzz" very quickly, but the effect is also short-lived.  So equate that to absorbtion of protein and other nutrients.  So we quite possibly could absorb it quickly, but it moves through so rapidly that we don't have the opportunity to get full benefit (malabsorbtion).  This is why I typically double-up on my servings to get as much benefit as possible while it's in my system.  So there could be validity in the notion that we're limited on what we can absorb, it's the amount that I question most.  Is this warped thinking?????      This is the extent of my analytical thinking...precisely why I was not a math or science major.  Regardless, I found a formula that worked for me in spite of it.  I do know - the more protein I took in during my weight loss phases - the more I lost, and the more consistent my loss was. Where the heck is Dx - I want him to weigh-in on this topic!!!  Cards Fan "STEP OFF THE SIDELINES AND GET IN THE GAME!"

DX! We need you!

I’m just back!!! Opened my show in Atlanta and I’m playing ‘Catch-up’ with the rest of my life this weekend! As for ‘studies’ about absorption, Dr. Douglas Hess (of Duodenal Switch fame) published a 10 year study that measured the content of fecal output against dietary intake in order to accurately calculate mal-absorption rates. Here’s a Crunch down of some of the numbers- for RNYers: Fat Amount malabsorbed: 38% Protein malabsorbed: 18% Carbohydrates malabsorbed: 3% for DSers: Fat Amount malabsorbed: 81% Protein malabsorbed: 19% Carbohydrates malabsorbed: 1% For Non/Pre-Ops: Fat Amount malabsorbed: 8.2% Protein malabsorbed: 2% Carbohydrates malabsorbed: 1% It was in the non-absorption of proteins in the Non-Ops that Hess reported variances depending on amounts eaten in a single meal. Due to the speed that food passes through the intestines, anywhere from 25gms to 40gms could be absorbed as the food passed through. So, depending on how quickly the food passed through, it was true that a range of 25 to 40gms of protein was the maximum that could be processed and absorbed by the digestive tract "at one time." The arbitrary "maximum 30gms of protein at once" is some ones distillation of the study. The speed that food / protein passes through the digestive tract would be influenced by- Hydration, fat content, roughage/fiber content, consistency and degree to which the food had been chewed, etc…. So, "30gms max?" Med-Urban Legend. But one based on some information. I think it would be safe to say, if you chomp down 60gms of steak with a salad, some of it is going in the toilet un-used. Best Wishes- Dx

Hi Dx,

I'm a little curious about the carb figure, since I seem to be able to eat just about any amount of carbs I want and not gain weight. Even with the amount of exercise I'm doing, pre-op this would not have kept the weight off. I'm sure some days, with the quart of skim milk and quart of apple juice I'm drinking that I'm at 4000 calories, yet I don't gain weight.

Is there anything that could be off about the study? Are the carbs maybe only refined sugar carbs? Or is it just a matter of a few people being way off of the averages? Or, is it just that I've barely broken the one year mark?

Thanks,

Dave

Hey Dave, I don’t know… The figures were taken from a 10 year study. It focused only on stable weight Post-Ops 5+ years out. The crux of the study was looking into re-growth of intestinal villi over time as the body compensates for restricted caloric intake. It found only marginal/insignificant increases in absorption. I copy/pasted it into a word-doc in my hard-drive some years back. I got it from Diane Cox (goes by HamletCox on that ‘other site.’) She was the Queen Mother of DS here for years. Dr. Cox has "the goods" when it comes to Absorption and Complication rates. (a particular interest of mine for reasons…) She had/has membership to all of those studies sites where you have to buy the membership to read more than an abstract. Quite the scholar. Perhaps drop her a line ‘over there’ or ask if someone has the complete study over at- http://www.duodenalswitch.com/forum/ That place is teaming with research fiends. Best Wishes- Dx