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562 Grams of Protein?!​

Still know someone who thinks high-protein diets are bad for their organs? Send them this. Also, check out this crazy new study.​

High-protein diets are bad for your health. Also, the Earth is flat, politicians are universally honest, and 5'7" white guys are always the best basketball players.

Those last three statements are clearly ridiculous, but aren't high-protein diets known for causing kidney and liver problems? No, they're not, but you've probably heard that all your life. Even today, when a positive protein-intake study trickles into the mainstream media, the writer predictably tosses in a cautionary paragraph about kidney or liver health, usually with an air of smugness.

Where did this fairy tale originate? And what do modern studies using extremely high protein intakes tell us?

Where Did the Protein Myth Originate?​

Your liver and kidneys play a big role in protein metabolism. The kidneys filter out waste products like urea and the liver processes amino acids. Too much protein, it was thought, would strain these organs.

However, the "strained organs" theory was based on studies of people with existing kidney disease. And it was just that – a theory. Doctors thought excess protein might exacerbate their disease by increasing kidney filtration rates. Maybe protein restriction would ease the strain, they thought.

In some cases, it seemed to. In other cases, protein restriction didn't do anything. But this idea was generalized anyway and applied universally to healthy people without kidney problems. It's like saying that since a few men with heart problems have died of heart failure during sex, the act should be avoided by all healthy men. (It's actually worse, though, because no one with kidney failure actually died from "excess" protein.)

Yes, a very high-protein diet can cause more urea production, but this doesn't overburden the kidneys. Healthy people's kidneys adapt just fine. As with weight training, the body adapts to the initial "harmful" strain.

The same is true with nitrogen balance. Early studies on athletes showed that higher protein intakes led to higher nitrogen levels in the blood. "What if it builds up and causes organ stress?" the researchers asked. Well, it doesn't seem to and, again, the body is adept at handling increased nitrogen.

There was also some initial confusion with animal studies. Some early animal studies linked high-protein diets with adverse effects, but the extrapolation to humans was often flawed due to metabolic differences.

Finally, the myth was somewhat encouraged by public health organizations. They worried that eating a lot of protein would cause people to eat fewer grains. Insert your own conspiracy theory here. Vegan groups didn't help either. To get you to eat fewer animal products, they often tout the "protein is bad for your kidneys" myth.


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New Protein Science and the Bodybuilder Study​

Dozens of recent studies show that high-protein diets are safe for your organs, benefit metabolic health, preserve muscle, and lead to fat loss due to protein's effect on satiety and thermogenesis. Even people with pre-existing kidney or liver conditions are no longer told to avoid protein, but some docs still suggest a moderate intake for those patients, just in case.

One recent study took protein intake to the extreme, just to be sure. Researchers recruited five bodybuilders who were already consuming high-protein diets. These men had been in a previous protein study and the researchers wanted to see what would happen if they continued with even more protein for another year.

The bodybuilders were provided with protein powder to ensure they met their protein minimums, and some took full advantage of the free shakes:

Subject 1: 206 Pounds

• Baseline Protein Intake: 138g
• Year One: 217g
• Year Two: 255g

Subject 2: 161 Pounds

• Baseline Protein Intake: 193g
• Year One: 278g
• Year Two: 285g

Subject 3: 218 Pounds

• Baseline Protein Intake: 395g
• Year One: 524g
• Year Two: 562g

Subject 4: 182 Pounds

• Baseline Protein Intake: 184g
• Year One: 250g
• Year Two: 222g

Subject 5: 182 Pounds

• Baseline Protein Intake: 163g
• Year One: 198g
• Year Two: 200g

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What Happened?​

Their kidneys exploded. One guy's liver shot out of his butt, flopped under the leg press machine, and was never seen again. No, I kid. The researchers concluded there were no harmful effects on kidney or liver function.

In some subjects, a few clinical values were slightly outside the normal range, but there was no consistent pattern. Most showed a fluctuation of BUN (blood urea nitrogen) and creatinine, but for some, their numbers actually improved by the end of the two-year study.

But what about subject 3? He's the guy who understood the assignment and consumed over 500 grams of protein daily. He did have high levels of BUN at years one and two, and higher levels of creatinine at year two. But, it didn't harm him. Interestingly, he also went from 18 to 13 percent body fat during the study.

Also, the researchers note that acute exercise by itself can result in an increase in BUN and creatinine. Plus, people with more muscle mass usually have higher baseline creatinine levels anyway.

How to Use This Info​

No, you don't need to consume over 500 grams of protein daily. That's nuts, but it also doesn't seem to hurt anything except the poultry population. This study merely reminds us to ignore the protein-deniers.

Here are some general protein guidelines to keep in your back pocket:

• To meet your daily protein threshold (the minimum amount of protein needed to control appetite), 15 to 25% of your diet should come from protein, or roughly 85 to 138 grams per day based on studies.
• To build and sustain muscle (fuel protein synthesis), consume about .8 to .9 grams per pound of body weight.
• For increased satiation, fat burning, and calorie offsetting, shoot for 1 gram per pound of body weight. If you're on a strict diet, go for 1.2 grams.