Too much protein? Is that a thing?

This article is dedicated to all the bro science enthusiasts out there who are promoting a culture of protein shakes, protein bars and protein all day every day simply based on hearsay and under the influence of false advertising from the meat and dairy industry. I bet that most of these guys counting there protein intake are deficient in nutrients like fibre and Vitamin D. Why are these guys so stuck on counting their daily intake of just this one macro nutrient, protein? Why not also count the other macro, micro, and phyto nutrients? If you have heard of people suffering from protein deficiency in the developed world then you can stop reading this article since you’re not going to find anything useful here. But if you have heard of chronic diseases such as heart disease, cancer, diabetes, and many others that plague our modern society, then please keep reading.

Before we dig in I would like to share my personal story and the reason why I am interested in finding the ‘correct’ answer to this question. I was born and raised in India on a mostly plant based diet comprising of fruits, vegetables, grains, nuts and legumes with the occasional meat, maybe a few times a year. Meat was expensive and considered a delicacy. In India, nobody counts calories or measures the intake of macro nutrients in their diet. We ate when we were hungry and stopped eating when we were full, simple as that. And fortunately through out my time in India I was healthy as a horse. But when I moved to Canada at the age of 19, I was introduced to a new food culture and I am talking in particular about Protein. In Canada, I see Protein products being advertised for weight gain and weight loss simultaneously. Seems weird, doesn’t it?

My first meal in Canada was a chicken pita wrap with fries from Opa. I struggled to finish the chicken wrap and I had not even touched the fries yet. I was full and thought to myself, how do Canadians eat so much chicken and food in one meal? But gradually I got used to the big meals and a meat heavy diet. I did gain weight, a lot of weight, about 40 lbs but since I had also started strength and weight training, I would assume half of it was muscle mass. I am 27 years old now and my health has been deteriorating over the years in Canada and I have always blamed aging, and the high stress, struggling life of a newcomer in Canada. But I am starting to wonder now that maybe the reason for my sub optimal health is my new found diet, the ‘High Protein’ diet.

I recently came across a fascinating book called Proteinaholic: How Our Obsession with Meat Is Killing Us and What We Can Do About It by Dr. Garth Davis. The author is a bariatric surgeon and has done extensive research on animal protein and its impacts on human health. Everything mentioned below is based on this book and the author’s research.

The bottom line of the book is that the inhabitants of the western world consume more protein than is required and focus too much on calorie counting. There are three beliefs that most people hold very dearly:

Belief 1: Protein is the most important nutrient.
Belief 2: The only place to get protein is from animals.
Belief 3: Our health problems largely result from not adhering to Belief 1.

I wasn’t aware of these three beliefs before I came to Canada but over time these beliefs were involuntarily ingrained in my psyche. I can’t tell if it was the successful advertising strategies of the meat industry, well meaning advice from friends and acquaintances or the body builders I met at the gym that unknowingly helped solidify these beliefs for me. I always worshipped protein as the sacred ingredient in my diet, especially animal protein. But this belief was crushed after I finished reading The China Study by Dr. T. Colin Campbell. The scientific research and epidemiological studies demonstrating negative impacts of animal protein on human health were just too convincing and impossible to ignore.

But I still had doubts. How can something like animal protein be bad for human health? Didn’t our hunter gatherer ancestors live on wild game? Aren’t we biologically omnivores? So I kept researching and found books such as How not to Die by Dr. Michael Greger which touched on this subject and eventually came across the book Proteinaholic, the holy grail of research on animal protein. The author, Dr. Garth Davis has done extensive research and his efforts are praise worthy regardless if animal protein is good or bad for human health. I don’t know if it was coincidence or destiny but Dr. Davis’ book has eradicated any doubts that were lingering in my mind on this subject. I have completely changed my diet as a result and have been a vegan for sometime. My health has never been this great before and I have so much more energy now that I don’t know what to do with it.

What does Science say?

So let us get to the bottom line. How much protein is actually required in our diet? Personally, I wouldn’t focus so much on this one macro nutrient. If one is eating a healthy diet rich in fruits, vegetables, nuts, seeds, legumes and whole grains, I don’t believe in counting calories or keeping track of the ratio of macronutrient intake. And yes, it still doesn’t matter if you’re an athlete or a couch potato. But who cares what I think, I am not a scientist or a role model of health. So let us look at what the experts, Dr. Garth Davis, Dr. T. Colin Campbell and the latest research has to say.

While I was reading The China Study, the one experiment that really caught my attention was a lab study conducted on rats by Dr. Campbell and his grad students. They fed rats aflatoxin, a carcinogen that mutates normal cells into cancer cells in the liver. What they found in these rats was truly remarkable, the development of tumor cell precursors in the liver of these rats were almost entirely dependent on the amount of protein consumed, regardless of the amount of aflatoxin consumed. Protein used for these experiments was casein, found in cow’s milk. Dr. Campbell and his team further discovered that tumor cell precursors grew far more in the rats fed a 20% protein diet than in rats fed a 5% protein diet. They also discovered that they could turn tumor cell growth on or off by varying the amount of protein in the diet demonstrating that cancer growth can be promoted or reversed by increasing or decreasing the amount of protein in the diet. Dr. Campbell’s study concluded that tumor cell precursors didn’t develop with up to 10% dietary protein. Beyond 10%, tumor cell growth increased dramatically with increase in dietary protein[1,2,3,4,5,6]. Another fascinating discovery from this study was the fact that not all proteins are alike. Gluten, the protein of wheat, did not produce the same result as casein, even when fed at the same 20% level[7]. Is there such a thing as too much protein? Based on these studies, the answer would have be a firm, YES.

One might argue how these studies on rats relate to humans? To answer this question one needs to understand why Dr. Campbell decided to conduct these studies in the first place. Dr. Campbell, as part of a research team, was assigned to solve the problem of a growing number of children, under the age of 10, dying from liver cancer in the Philippines. Dr. Campbell and his team identified alflatoxin, a carcinogen present in moldy peanuts and corn, as the cause of liver cancer in these children[8,9]. Dr. Campbell states “All twenty-nine jars of peanut butter we had purchased in the local groceries, for example, were contaminated, with levels of aflatoxin as much as 300 times the amount judged to be acceptable in U.S. food”. They further investigated to find out who was most susceptible to this aflatoxin contamination and its cancer-producing effects. In order to do this, Dr. Campbell’s team collected epidemiology data on liver cancer in children in the cities of Manila and Cebu. With this data in their hands, Dr. Campbell states his surprise at it “Namely, the children who got liver cancer were from the best-fed families. The families with the most money ate what we thought were the healthiest diets, the diets most like our own meaty American diets. They consumed more protein than anyone else in the country (high quality animal protein, at that), and yet they were the ones getting liver cancer!” These findings fueled Dr. Campbell’s curiosity and lead to the animal studies conducted in rats confirming what Dr. Campbell was witnessing in the Philippines.

In order to build muscle we don’t need protein specifically. We need the building blocks of protein i.e. amino acids. Our bodies can synthesize every protein required, if our diet includes all the essential amino acids. Our bodies also have the ability to recycle amino acids, they are not excreted in case of muscle breakdown. So moral of the story is that our bodies don’t have a shortage of amino acids, on a healthy diet. What the body needs to build muscle is calories i.e. energy from carbs and fats and not amino acids. Another factor that determines how efficiently we recycle urea and nitrogen into absorbable amino acids in the colon is our gut flora[10]. And who tends to have a healthier gut microbiome – vegans, vegetarians, or the proteinaholic non-vegetarians? Apparently, studies suggest that vegans have a healthier gut flora which further suggests that it’s possible for vegans and vegetarians, to synthesize all the protein they need in spite of their low protein intake due to their more efficient colonic reabsorption of amino acids[11]. Studies have also shown that some of the so called essential amino acids that we supposedly only get from our diet can be synthesized by the bacteria in our gut[12,13]. So if you’re a proteinaholic, I would suggest you start with improving your gut flora, not a protein bar. Studies have also shown that there is an upper limit to how much protein our bodies can use for building muscle. Once this upper limit is reached, more protein doesn’t equate to more muscle[14].

In the 1940’s, William Rose identified the eight essential amino acids that humans cannot metabolize themselves and must be obtained from diet. Dr. Garth Davis, in his book Proteinaholic, clearly states that “Each of these amino acids is well represented in just about all vegetable foods, including white potatoes, wheat flour, and corn. There’s absolutely no way you could eat sufficient calories of a varied plant-based diet and become protein deficient”.

The current U.S. government Recommended Daily Allowances (RDA) for protein is 0.8 g/kg of lean body mass, which aligns with the latest research[15]. So for example, if you weigh 72 kilos, and have a BMI of 20, your lean body mass is 72-0.2×72=57.6 kilos. Hence your require 0.8 x 57.6=46.08 grams of protein a day. Studies have concluded that there are no differences in protein requirement between the younger and older adults and the current RDA of 0.8 g/kg of lean body mass is adequate[16]. So if this person weighing 72 kilos is eating two slices of whole wheat bread with a cup of oatmeal for breakfast, a cup of boiled lentils for lunch, a cup of boiled beans for dinner, along with a cup of brown rice, this person has already exceeded his/her RDA requirement for protein. Not to mention the protein you get from your veggies such as broccoli, kale, asparagus, or zucchini and fruits such as avocados or bananas. Most people would generally need to eat more food in a day to meet their daily caloric requirements, so you can imagine how there is no way to be protein deficient as long as you’re not on a starvation diet.

The most common question is, what if I am an athlete? Do I need more protein than the RDA recommendation? A very large scale 2005 study produced by a joint US/Canadian Dietary Reference Intake Committee stated on page 150 of the report that “Since compelling evidence of additional need is lacking, no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise.” The study also reported that there is no evidence to recommend a different protein requirement for vegetarians. You can read the report here. To get the most out of your workouts, athletes must consume 20 grams of protein right after working out[17]. Anything in excess of 20 grams is going to waste and causing harm to your body as shown in studies[18]. Your body struggles to get rid of the excess protein taxing your kidneys[19], leading to oxidation and excess ammonia in the body. That being said, if you’re still concerned that a protein intake of 0.8 g/kg of lean body mass is not enough for you, there is some older research suggesting that endurance athletes and body builders may need more protein, 0.94 g/kg of lean body mass[20].

Dr. Davis sums it up perfectly, “In general, for the average person, the RDA is more than sufficient protein for an active lifestyle. For the very active weekend warrior, trying to get big or fast, 1.0 g/kg with 20 grams after workout may be ideal. For bodybuilders, I am not sure it is all that different but some do suggest 1.8 g/kg. Probably for the Olympic endurance athletes 1.8 may possibly be the right amount. I am being vague because the data is vague.”

In the end, I just want to mention athletes that seem to defy this protein myth of “more protein equals better performance”. How do you explain Michael Arnstein, the ultrarunner who lives just on fruit? Or how do you explain the growing community of vegan bodybuilders and endurance athletes on Or Dr. Garth Davis himself, who is a vegan marathon runner and doesn’t count his protein intake? Beats me!


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