I am on a low carb diet also. I work out 5-6 days a week. I've lost 38 lbs. I have 70 to go. (10 before I joined MFP). I believe that as long as your are taking a good multivitamin. (I also take vitamin d). Know your body, visit your doctor and have blood work done regularly. I have found a low carb diet is the easiest way for me to loose. I feel like I have tried everything there is. It is the easiest for me to follow. But as far as the cons: Some things I've read that say it isn't good: Many experts believe that there is significant risk of heart attacks in individuals who are on low carb diets for a long time. Low carb dieters tend to eat a lot of saturated fat. Many theorize this is bad for the heart and due to the increased cholesterol levels, the risk of heart attacks increases. I've read that we may however experience some minor side effects such as bad breath, muscle cramps or exhaustion. There may not be any adverse effects on health unless the individual is suffering from kidney disorders.
I changed my goals to show only calories and carbs. It bothered me seeing the protein side always over. Right or wrong I made a promise to myself again, that I am going to loose this weight! Friend me if you want to! Good luck to you on this adventure!

Too much protein can convert to sugar. Best stick to .75 - 1 gram of protein per body weight. Fat, on the other hand, is your very best friend!

Edit: For the record - my goals are set to 10/30/60, but I don't get upset if I go a little over, especially on lifting days.

Careful there, DV. Rabbit or squirrel starvation is due to an ABSENCE of essential fatty acids, not an excess of protein. If excessive protein is so bad for you, explain the Inuits who lived exclusively on fish, meat, and blubber. Or the Masai, who lived exclusively on milk, beef blood, and beef. Paleo folks can point you toward a study in 1910 or 1920 where two guys were chaperoned day and night to make sure they ate nothing but meat for a year and had there health monitored. They did fine. Food for thought. Why didn't the Inuits get scurvy from lack of vitamin C, but the polars explorers did?

The RDA for just about any macro nutrient is a bunch of bull****. For most people to have side effects from taking in too much protein you'd have to eat an inhuman amount (read nearly impossible) daily for potentially years or decades to see an effect. This is of course assuming you don't have other medical conditions that are adversely affected by protein and are basically "normal".

Secondly I'd like to point out that with a low carb diet, the goal is generally to be low on carbs and high on FAT, not protein. It just so happens that to keep carbs low, we turn to animal meat, which in turn increases our protein intake, but the goal is to ensure that we are replacing carbs as a fuel with FAT. So make sure to eat that chicken skin, the beef fat, the pork fat. Cook in lard, tallow and coconut oil. Make sure to eat the egg yolks and don't shy away from bacon, pork rinds and all manner of other things you've been told forever are bad for you.

And to the OP, just eat, live and loose weight. Don't worry about the protein intake, chances are that you're well within the bounds of acceptable levels for any normal person.

Paleo folks can point you toward a study in 1910 or 1920 where two guys were chaperoned day and night to make sure they ate nothing but meat for a year and had there health monitored. They did fine. Food for thought.

They weren't chaperoned the entire study, but monitored throughout the year (the report actually states that they were of high character, etc). Also, when one of them ate mostly protein to start (the 2 guys started at different times), with little fat (at the researchers' request), he was getting sick - he had to request to be allowed to eat the liver, brain, etc for additional fat. Once he ate the additional fat, the ill effects went away. Now, whether this was from too much protein, or not enough fat, not sure. Or both?

http://www.jbc.org/content/87/3/651.full.pdf+html

Yes, there are side effects of too much protein...

Weight gain: excess protein could be stored as excess fat.
Stomach upset: most likely constipation but it could swing the other way with diarrhea or gas/bloating.
Dehydration
Seizures: there's been some linkage to seizures and high protein consumption but it's usually been only if high protein is consumed and not enough water - basically the dehydration effect of too much protein then can lead to seizures.
Increase in liver enzymes
Nutritional deficiencies: but, only if you focus solely on consuming protein and forget about carbs, fats, vitamins all together.
Risk of Heart Disease: depends on what types of protein you're consuming - if it's fatty meats all day, evey day then obviously the cardiovascular risk rises but, if you're doing other sources that are low in fats then no worries here.
Kidney problems: this hasn't been researched fully but it's suspected that high protein, over long periods of time, can eventually harm kidney function.

Please provide valid data to back this up.

1. The chances of protein being stored as EXCESS fat, unless you are also eating too many carbs seems pretty dubious to me.

2. While I can't speak for everyone, I think you'd have to be eating an ungodly amount of protein for this. I've gone as long as 2 months before taking in NOTHING but meat and was never more regular. You DO NOT need carbs or fiber to defecate normally.

3. What evidence is there? Dehydration I'm sure can cause heat related injuries and other damage to organs, but the link between protein and dehydration seems flimsy at best?

4. Increase in what liver enzymes? Is this actually even a problem? Are these enzymes detrimental to human health?

5. This I could see if you are eating absolutely nothing but processed protein with no fats or other nutrients present. Typically hard to impossible if eating from animal sources.

6. There is no increased risk of heart disease with the increase of fats! This is the boogeyman that the low fat crowd has been pushing since the Lipid Hypothesis, and it's flat out wrong. You are more likely to have heart issues and horrible lipid profiles on a low fat diet. Eat all the fatty meat you want...all day every day and you'll notice nothing more than weight loss and better cholesterol panels.

7. Here's another low carb boogeyman. Unless you have impaired kidney function or other kidney disease, increase in protein is not an issue. This is a falsehood that has been spread by the media and others to keep people on the low fat side of the fence.

You conveniently left out the rest of my post in the quote...I plainly agreed with most everything you've pointed out and said that it's likely a complete non-issue for the low carb dieter unless they're doing nothing but eating slab after slab of fatty beef and, especially if they're cutting calories too; it would be impossible to consume a high enough amount of protein to ever reach levels that would do harm....

"Now, with all that said...I seriously doubt you'd have anything to worry about. Unless you're just consuming all protein in your diet with no carbs at all, no veggies; just plate after plate of fatty meat and then have protein shakes for dessert in between, lol, then it's likely you'd never consume enough protein to ever get to the point of any of those effects; especially if you're limiting calories as well because it would be impossible to consume enough protein to do harm on a 1500 calories diet, even if you did eat it all in protein. And, a lot of those effects are really all one in the same; one thing kicks it off and the rest are caused by each other.

RDA says about .4 grams per lb per day and up to 1g per lb per day for more active people but I have always found the RDA to be full of crap. There is ZERO need for our bodies to consume 300 grams of carbs per day. That's ridiculous - but that's a whole other rant, lol....watch Fat Head if you haven't...

Anyway...I personally think it's totally safe and acceptable to even go above the RDA's limits so that leaves you with a huge amount of protein that you can consume in a day safely. Unless you're totally inactive and just sitting around eating slab after slab of fatty beef as your only protein source and consuming 600 g of it a day, you're likely not going to have to worry about any of those issues. If you're getting your protein through dairy, meats, fish, and a variety of sources, staying active, and still getting veggies too then you should have no problems, even if you do have several hundred grams a day."

But to answer your question about backing up the info; I found it on medicinenet.com, the Mayo Clinic's website, advice for health website, and then a few others like Live Strong also say the same thing.

As far as the dehydration; the theory is that low carb causes excess keytones which can lead to keytone toxicity and cause the kidneys to have to work harder to flush out the toxins. That, in turn, is supposed to lead to the potential kidney issues. And again; not my agreement - only what medical research supposedly says will happen with a high protein diet but once again - high protein is not the same for everyone - they don't classify what "high" means - 200, 400, 600 grams a day? It all goes back to it's likely impossible for the average person on a low carb diet, exercising, watching calories, etc to ever consume that much.

As far as the fats/cholesterol link - I believe I mentioned the movie Fat Head in my OP; it talks about that a lot and I recommended watching it so as I mentioned earlier - I was simply pointing out the listed effects of too much protein for the OP - not agreeing with it.

Biggest side effect of too much protein is continued weight loss.

Justin, please give us some documentation of Brock Lesnar's diverticulitis being caused by excessive protein intake. Diverticulitis is a degenerative disease of the colon. As a physician, I can't understand how that conclusion could be reached. I can understand somebody speculating about the two being linked. I can understand that being somebody's opinion. But I can't understand how there could be any meaningful proof of it. Please share your sources.

The only thing I could see this as an issue is that low carb can often times make the bowels slow digestion-wise because it's a low-fiber diet. Low fiber can mean things aren't moving in intestines and sit causing bacteria in the pockets of the intestines which can make diverticulitus. That's just my assumption though and could be solved by taking fiber every day. Or adding fiber to the diet.

Low-carb doesn't have to be low-fiber, and it doesn't necessarily cause problems with irregularity. I'm more regular now than when I ate more fiber with those nasty "whole grains". And I get just as much fiber as when I was eating SAD (standard American diet), but it's quality over quantity of the fiber.

And the intestines already contain bacteria. It (bacteria) turns the soluble fiber into short-chain fatty acids.

"Low carb dieters tend to eat a lot of saturated fat. Many theorize this is bad for the heart and due to the increased cholesterol levels, the risk of heart attacks increases."

This is what wikipedia calls "weasel words". WHO theorizes that? No one who has medical or nutritional training since 1997, I'd wager. It's been clearly shown that saturated fats are not strongly linked to either of these things.

Biggest side effect of too much protein is continued weight loss.

Justin, please give us some documentation of Brock Lesnar's diverticulitis being caused by excessive protein intake. Diverticulitis is a degenerative disease of the colon. As a physician, I can't understand how that conclusion could be reached. I can understand somebody speculating about the two being linked. I can understand that being somebody's opinion. But I can't understand how there could be any meaningful proof of it. Please share your sources.

Protein consumption replacing whole grains, fruits and vegetables in a low fiber diet may cause problems for the GI tract.. that is general knowledge I thought. Bodybuilders tend to do this exact type of diet.

I also must correct myself, Lesnar didn't have diverticulitis.. he had diverticulosis

What evidence is there that replacing foods such as whole grains with a protein rich diet causes GI issues? I would argue the exact opposite that whole grains are the leading hidden cause of GI issues and GI distress in most people. Grains and especially gluten are not tolerated well by the human body, though people may experience varying degrees of symptoms.