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the downside of protein?

I’m in this nutrition class at school. So far I haven’t learned much of anything. However, today our prof started talking about protein and how large amounts are not necessary for muscle growth and developement. Being an overweight 50 year old woman that comment didn’t suprise me. What did intrest me was she pointed out a number of negative side effects of a high protein diet some of these being:

  • Calcium excretion leading to weaker bones. (I know weight training promotes stronger bones but she said this still occurs.)

  • Throwing off your bodies acid/base balance leading to the kidneys and liver working overtime and causing damage.

  • Increasing your need for vitamin B6.

I’d love to hear some feedback on these. Do a hyper-caloric and high protein diet cause problems in the long run?

Well, your prof was telling you these things from nutritionist point of view. A high protein diet is not necessarily healthy in that, yes, it is a bit taxing on your kidneys due to the increase in GFR caused by a lot of amino acids vasodilatory effects. Also, high protein intake means high nitrogen excretion so the urea cycle (liver)is going to be in overdrive. But in all of my studies, and from hearing many seminars, most truthfully I think that a high protein diet is unnecessary for an elite athlete. Key words here being “elite athlete.” For many people here, recreational bodybuilders I assume, however, we must intake higher calories to maintain weight without putting on fat. This is where protein comes in. It is the last macronutrient that will be converted to fat in a hypercaloric diet. So if your concern is bodybuilding, a high protein diet is the way to go. There are also many other benefits ot high protein, just read one of Berardi’s essays on protein turnover. But your teacher is by no way incorrect.

This is a case where theory just doesn’t meet up with actual results. It’s also a case, where the potential negative effects are usually countered by other factors that accompany a higher protein intake.

Regarding the calcium excretion, well a lot of people get their protein from dairy sources, thus bumping up their calcium. Also, most of these people eat more calories and thus are more likely to get enough calcium. Not to mention that heavy resistance training increase bone density.

As for the kidney and liver damage, it just doesn't show up in normal, healthy peopl in the short or long run.

A lot of things sound good and make sense scientifically (at least of the surface), but there is always many other factors to consider.

search this forum archives as well as t-mag’s. Ask your “enlightened” teacher is she knows of formers football players, strength athletes, farmers and so forth if they have a higher incidence of kidney, liver damage as well as weaker bones compared to the general population…

Weaker bones LOL, studies in OLifters found they have a way higher bone density than “normal” people, yet they typically ingest 2,0-3,0+ grams of protein/kg.

Your teacher is probably another mainstream(so bad)product. Ask her those simple questions but don’t wait for a bright answer. Such is the way of mainstream education.


This one gets covered every month or two on the forum. I’ll respond over a few posts.

First, the idea of the kidneys and liver failing due to working overtime is crap. Let me ask you this: exercise causes the heart to pump more blood (increase cardiac output), essentially doing “overtime,” so why isn’t exercise bad for us?

Here’s an excerpt from Cy Wilson’s “Smart Answers to Tired Old Arguments” here at T-Mag. I should mention that his statement on the replenishment of calcium “leaching” being rather easy was supported by a well structured study at the 2002 Experimental Biology Conference in New Orleans; I don’t suppose your professor was in attendance. If she was, though, she must have been at local IHOP during that presentation:

Tired old argument #3 : Too much protein is dangerous!

This is bullshit and you should challenge them to find any evidence that demonstrates a high protein intake having any deleterious effects in normal humans who aren't suffering from renal failure.

Since they’re basing that statement on info derived from studies done with patients who had renal failure, they won’t be able to produce any evidence. Oh, and if they want some “real world” or anecdotal evidence, you can point out that all of those weightlifters and athletes who consumed high amounts of protein since the 1950’s and still continue to do so today have no problems with renal function. If it were true that a high protein intake caused kidney damage, then you’d expect the very opposite ? a virtual epidemic of kidney disease among lifters.

Likewise, the tired old chestnut about high protein diets leading to calcium deficiencies and eventually, brittle old bones is also bullshit. True, high protein diets can cause some calcium to leech out of bones, but the amount lost in a single day can usually be replaced by the amount of calcium contained in single tablespoon of milk.

Ef, you would do better to dump your nutrition class and just spend your time reading back issues here. Cheaper and better.

But just for kicks, I would really enjoy it if you asked your prof to give your a study that demonstrates increased protein consumption leading to kidney problems in healthy people. Ask and let us know what she says.

I need in the Dawg Pound…

yeah. I just took the class because I needed something else to put on my schedule, it really hasn’t given me any good information. I’ll ask my prof about what you guys have said and see what she has to say.

look, you’re being naive. every diet has its downsides, you can find similiar evidence for eating a FDA pyramid balanced diet, a high carbohydrate diet, a high fat diet, etc. if you’ve identified the specific weakness of your diet, you can fix them through supplementation, lifestyle changes, or slight modification of your eating habits. the body is also an adaptive organism, while initially a high protein diet may be stressful on the kidneys, they will adapt to it. calcium excretion won’t lead to weaker bones, the major cause of weak bones is inadaquate lifestyle stress to promote bone density, no calcium deficiency like some major supplement/pharmaceutical groups would like you to beleive.

increasing food consumption also leads to more vitamin and mineral intake so the effects of eating a high protein diet are neutralized. Also we should be drinking enough water and their are supplemental vitamins and minerals. laters pk

Ef, have your prof. show you the studies which prove the kidney theory. Laymen claim this but no one has proof one that it’s true. Too much theorizing not enough facts. Croooz

ef, you might find the following link helpful;
www.totalfitness.com.au/ mythsaboutlowcarbdiets.htm
Search out and read reference 51, the review by Massey. High protein diets have been shown to increase calcium excretion, but whether or not this leads to bone loss is highly debatable; a number of studies show high protein eaters to have stronger bones - and at any rate, eating alkaline ash foods like veges and fruit, which is common sense, largely negates the rise in calcium excretion. There are also refs in the article for a couple of studies on protein and kidney function. In short, your professor needs to pull her head out of her ass and supply some solid evidence for her assertions - don’t hold your breath waiting for that to happen though.
Best of luck.

The amount of calcium leeched out can be replaced by a teaspoon of milk. No big deal. T-mag covered this a while back. Nothing to worry about.

I’ve often noticed that those that worry about little, insignificant crap like this tend to screw up on the stuff that really matters. Like the other day a smoker told me how protein was “hard on the kidneys”. A friggin smoker! Usually I just tell them that the advantages greatly outweigh the disadvantages.

Awhile back, I took a nutrition course in college. The professor was, of course, a “pro-Food Guide Pyramid where most of your foods should come from grains and starches and very little protein blah, blah, blah, blah, etc.” During one lecture, her blood sugar dropped (gee, I wonder why) and she had to sit down because she couldn’t stand very well. She had a student go get her a Coke to get her blood sugar up again. Everybody in the class is sitting there stirred and bewildered about what all is going on. I, on the other hand, had my face in my hands doing my best to keep myself from laughing. If I wasn’t wanting to laugh so bad, I would have gotten up and walked out. As I sit here now, I should’ve walked to the front of the class and told her not to worry, that I’ll take it over from here and teach them why this had just occurred.

There is a bit of a culture here at T-Mag. "We know more than those idiot professors who have a better education than us, who base their knowlege on the scientific method, and finally and most importantly give us most of the in depth research and knowlege we pride ourselves on. You can come here and ask and get one answer only to have it refuted by the professor. What to do?? Choose hte path of ignorance and blindly join one or the other schools of thought or take some of it in and research in order to have a true understanding. Higher learning isn’t all bad. Consider that most well informed people have better things to do than sit on forums all day. In many cases they have their good name spoiled by 18 year old first year students and personal trainers. I dont think they care.

You people seem to forget that following any research these days is a Herculean task. There is a mass of published papers appearing every month. Researcher (or a professor) has a lot of things to do besides read them all, even if keeping up-to-date is very important for a scientist. Research on body-building has also a burden of frequently being sponsored by supplement companies, which automatically makes results have less impact factor. Furthermore, many professors have their own speciality field which is often very narrow. In other topics, they rely on info they have heard and learnt from others, and that info might be a bit outdated. Of course, being that this woman actually teaches nutrition, she should at least be aware that there are other approaches besides hi-carb nutrition. But professors are not omnisentient creatures. It’s just that she probably remembers research from several years ago when Atkins was on the firing line, and dangers of hi-protein were overemphasised. And you cannot actually say that wrong kind of hi-protein diet is not dangerous for couch potatoes (red meat, animal fats, cholesterol etc.)

Well, I can only speak for myself and the few others I know on this forum, but to say that we here at t-mag are not educated is, to say the least, an incredibly dumb thing to say. I myself have a MS in Nutrition science from the University of Tennessee, and will be graduating with my Doctorate of Pharmacy degree this May from Mercer University in Atlanta. Many others on this forum hold post-graduate degrees as well. The information we give is not a mantra, but rather insightful information garnered from both our substantial academic careers and our many years of real world training, trial and error, and reading on the subjects of bodybuilding OUTSIDE of our academic career. The burden of proof for protein being injurious to the body should be on those making the accusation. Show me one, jut one published journal article which shows protein causes negative renal effects. There aren’t any, I have looked and looked. Show me one attibuting osteoporosis to excessive protein intake. You won’t find them. By the way, the myth of excess protein leading to nephron damage comes from a faulty assumption, being elevated albumin, BUN, and SCr are markers for disease states in normal individuals. Not BECAUSE of the protein ingested, but because something is wrong WITH the kidney do these levels go up in normal people eating standard diets. When a bodybuilder comes in and has high levels of these markers, it is ASSUMED his kidneys are unhealthy, when in fact his body produces more of these things in greater QUANTITY, thus the greater excretion and higher levels. So its a bit of reverse, faulty logic. As a clinician, you should assess the patient’s lean body mass, as well as ask him/her their nutritional status before jumping to conclusions.

In regards to spouting “mantras”, it does seem like, due to a lack of proof, the mantra is being chanted from the other side.

Along the lines of this, i heard that the body can only absorb about 40 grams of protein every 3-4 hours, anything over this then essentially leads to fat development, is this true?


You ask the question to the right people. But here's my little advice. Although it'd be very satisfying to challenge your professor and show the class that she's a stupid fat moron, if your grades are very important to you, just suck it up, memorize her garbage, spit it out on the test so you can ace it, and then promptly forget all the garbage you memorized in her class as soon as the final's over. That way, you'll get a good grade. Pissing off a professor can have a very negative consequence on your course grade. And from what I observed, most professors are not open to new ideas, esp. the ones as brain-washed as yours. JMHO.