In my recent post, “Meat Is Not The Devil“, I talked about all of the reasons this country is terrified of eating meat. I’m surprised the American Heart Association doesn’t have a warning system in grocery stores about red meat like airports have alerts about terrorism. “According to our doctored, biased research today, there is an amber alert on beef. Fill your grocery carts with anything but red meat... Anything.”
It’s ironic to me that while we are made to feel guilty and almost sinful for eating a steak, not many Americans are afraid of Big Gulps (I witnessed one guy carrying one up a 15 minute hike in Kentucky. I mean I guess he needed something to keep him hydrated for that long, arduous trek…).
Whenever people find out I’m a nutritionist, their most pressing, food-related questions inevitably emerge. Among those questions, there has never been one about how many gluten-filled crackers are too many. Or if having brown rice every day is too much. Or if the sugar-laced, fat-free yogurt they eat every day is actually bad for them.
No, I don’t ever get those questions – the ones people should be asking. What I get is this: “You don’t eat grains and dairy? So you eat a lot of meat? Isn’t that much protein bad for your kidneys???” Seriously guys, come ON. My MEAT, that most basic, prehistoric food, is bad for my kidneys, but your daily 64 oz Gatorade is good for yours? And your pastry for breakfast and your Snickers for lunch? And the nutrient-less bun that you add to your meat?
What exactly is a high protein diet? A lot of studies out there define high protein as around 30% of the diet. Cordain, in his protein debate with T. Colin Campbell (pdf) (which I HIGHLY suggest you read) states that “high protein” is 20-29% of the daily calories and “very high protein” is 30-39% of daily calories. What does that mean?
Alright, most Americans are eating around 15% of their daily calories as protein. That means if you’re an average American eating 2,000 calories per day (yeah, right – the average is more like 3-4,000), you’re getting around 75 grams of protein per day (or 300 calories’ worth). On a high protein diet, that same person would be getting anywhere from 100-145 grams per day. On a very high protein diet (30-39%), that person would be eating from 150-195 grams. See the chart at the bottom to see what that really means in terms of food consumption.
Here’s why a “high protein diet” isn’t bad for you.
As a disclaimer, let me say that yes, if you have already been diagnosed with kidney disease (likely from eating a high-glycemic, meat-deficient diet all your life), then you don’t want to eat a high protein diet (20+% of calories). Everyone else is in the clear, though. As they have been for 2.5 million years.
Minimum Protein Requirement
Now that we have that squared away, let’s talk about what our minimum requirements and maximum tolerances are for protein. Our trusty government has decided that a 19-70 year old man can get away with eating 56 g of protein per day. For an active, average man on a 2500 calorie diet, that’s about 9% of the diet. They actually think men might even thrive on that amount, never mind the fact that a 19 year old has incredibly different needs than a 70 year old… That’s about the same percentage that T. Colin Campbell advocates, along with many vegan-types: 10%. Sounds terrible.
Maximum Protein Intake
On the other hand, there’s this syndrome called rabbit starvation. It’s something that might happen to you if you were stranded in the woods for a week, living off of only very lean animals like rabbits and squirrels. That is, if you didn’t die first because you couldn’t figure out how to kill them (I’d surely die). If you did somehow overcome that little hurdle and manage to massacre a whole lot of the scrawny morsels, after a week or so you’d have an intense hunger for fat, and then diarrhea, nausea, cramping and eventually death. When your diet is so full of protein and so devoid of carbs and fat, that’s what happens.
When your liver is overloaded with protein, it can no longer make urea (a waste product from protein that’s excreted in the urine), and ammonia leaks into your bloodstream – not good. While this actually happened quite a bit during meager winters even a hundred years ago, it doesn’t happen too often these days. Not in America, at least.
Our liver’s upper limit of protein intake is about 200-300 grams per day, or about 35-40% of caloric intake (1,4). Rabbits are about 85% protein and 15% fat. The Paleo diet, however, should be roughly 30% protein, 40% carbs, and 30% fat (with some give and take with the carbs and fat). That keeps you safe from developing the rabbit syndrome because you have ample fat and carbs in your diet to balance things out, and it keeps you below the upper limits of protein intake. So yes, the Paleo diet has a higher protein percentage than the 15% in the American diet, but we see where that gets people.
So00, it turns out that it’s not your kidneys you need to worry about with eating too much protein, but your liver! What about your kidneys, though? Are those terrifying news stories about too much protein causing kidney damage all wrong? Yes, mostly.
Your Kidneys Can Handle It
The studies that have been done on the kidneys to scare you away from eating “too much” protein have been done on people who already have kidney disease. Look it up. Go to www.pubmed.com and try to find a study that provides evidence that eating a high protein diet will adversely affect a person with normally functioning kidneys. What they’re finding (and admitting now) is that people with normal kidney function do just fine on a high protein diet (5,6).
As the National Kidney Foundation states themselves, (not a high protein diet, but) “diabetes is the leading cause of kidney disease.” Let’s just let that sink in for a second. Once again, we’re seeing the irony in my cookie and cracker-fiending, Big Gulp-slurping friends’ questions about my meat. As it turns out, they should be WAY more worried about their own diet harming their kidneys, since we all know that diabetes is caused by a high-glycemic, sugar-filled diet. Which the Paleo diet is NOT.
So the next time someone asks me if I’m going to die of protein overload due to my outlandish consumption of meat, I will assure them that I’m not eating too many rabbits, so my liver is fine, thank you. And I’m not eating any refined grains or sugar, ahem, so my kidneys will be alright, too…
Protein Content in Common Foods
To put things in perspective, here’s a list of common foods complete with their protein content. You can find this and more at the USDA Food Database.
Meat and Eggs
Beef (6 oz.) – 54 grams
Turkey, breast (6 oz.)– 51.4 grams
Pork Chop (6 oz.)-49 grams
Hamburger (6 oz.) – 48.6 grams
Tuna (6 oz.) – 40.1 grams
Chicken, breast (6 oz.) – 37.8 grams
Salmon (6 oz.) – 33.6 grams
Egg (1 large) – 6.3 grams
Cottage cheese (1 cup) – 28.1 grams
Yogurt, low fat (1 cup) – 10.7 grams
Skim milk (1 cup) – 8.3 grams
Whole milk (1 cup) – 8 grams
Nuts, Seeds and Legumes
Soymilk (6 oz.) – 6.7 grams
Tofu (6 oz.) – 13.8 grams
Peanut Butter (2 Tbsp.) – 8.1 grams
Almond Butter (2 Tbsp.) – 7 grams
Lentils (1/2 cup) – 9 grams
Sesame Seeds (1 oz.) – 7.5 grams
Black Beans (1/2 cup) – 7.5 grams
Banana (medium)-1.2 grams
1. Protein Debate – Cordain Vs. Campbell – pdf
2. kidney disease and high protein – no correlation study – http://www.nutritionandmetabolism.com/content/2/1/25/abstract
4. The Paleo Diet, by Loren Cordain PhD