I’ve been a vegetarian since I was 12 years old, and I’ve been asked this question since I was 12 years old. Where do I get my protein? There is more to this question than meets the eye. Why did no one ask me where I get my beta-carotene? Where do I get my fiber? Why is protein the nutrient that even strangers seem to have a deep concern for in regards to my diet and health? It was this protein question, or perhaps more my own question of why I was being asked this question in the first place, that piqued my interest in nutrition and eventually led me to Bastyr University. Fifteen years after my decision to stop eating animals, with a graduate degree in nutrition, I feel that I can finally provide a satisfactory answer.
The question is taken to a whole new level when put in the context of hiking the Pacific Crest Trail. Walking 20-30 miles per day, the general consensus among thru-hikers is that high protein foods are essential for muscle recovery. In addition, our food options are limited to what we will carry on our backs. No marinated tofu steaks or soy burgers with cashew cheese.
After reading The China Study, I finally understand why there is so much concern with protein in our culture. Ever since its discovery in 1839, protein has taken center stage as one of the most sacred of nutrients (1). The word has its roots in the Greek word "proteos", meaning "of most importance" (1). It is a vital component of our bodies and functions in a multitude of roles to keep us alive. In the 19th century, protein was synonymous with meat, a cultural association that has stayed with us over the years. Having meat on the table is traditionally a sign of wealth and good health. Upon its discovery, the recommendation for protein was set at twice that needed to sustain the human body due to the cultural bias towards meat and protein and the idea that more must always be better (1).
That is the historical ground on which many people and health professionals still stand in their perspectives on nutrition. But if we take a step back, we start to see that there may be a different story. Healthy populations in Asia, South America and Africa, for example, consume a diet very low in animal protein and have disease rates a fraction of that in the Western World (2). Elephants, Giraffes and Hippopotamuses grow to be hundreds of pounds simply by eating leaves and grass. The full spectrum of amino acids can be found in every plant food (3). Even human babies thrive and grow on a diet of breast milk that is only 5% protein, the same amount of protein that is recommended by the World Health Organization for an adult (3). To put that into perspective, a diet made completely of fruits and vegetables that meets calorie needs is about 10% protein (3).
In the United States, the Recommended Daily Allowance of protein for a healthy adult is 0.8 grams per kilogram of bodyweight (4). For a 60 kilo (132 pounds) person, this comes out to be 48 grams of protein. Assuming a 2000 calorie diet and 4 calories per gram of protein, this corresponds to about 11% of calories from protein (9% for a 2500 calorie diet). The recommended 10% of calories (0.8 g/kg) from protein has been reviewed 14 times by a panel of expert scientists (4). Given that a potato is 8% protein, throw in a half cup of beans at 27% protein and we can easily meet or exceed our recommended protein needs on plant foods. By including animal protein and increasing intake to the 17% of calories found in the Standard American Diet, we put ourselves at risk of first, the adverse effects of animal protein itself, and second, displacing the health benefits of nutrient-rich plant foods (4).
So what does this mean to a thru-hiker? With such high calorie needs, we tend to eat more food in general, meaning we will naturally be getting more grams of carbohydrate, fat AND protein no matter what. We are not any more likely to become protein deficient on the trail than off. In fact, breaking down protein is hard work for a body that is already hiking 25 miles everyday. As excess protein cannot be efficiently used as fuel or stored like fat or carbohydrates, the liver and kidneys must breakdown, neutralize and filter all the extra amino acids (3,5). In addition, you actually lose a little bit of water through protein metabolism (5). The whole process puts extra strain on your body when the first priority should really be to feed your working muscles.
I heard a metaphor recently that put things into perspective. It’s like maintaining a house after it’s been built – you can’t do it by constantly providing more walls, floors and ceilings, you need to pay the utilities, keep the lights on, and keep it clean. Proteins are the walls. Carbohydrates keep the lights on.
I remember once, hiking through the North Cascades, I had a protein shake for lunch. My body was so busy putting energy into breaking down that protein that I had nothing left to hike. More blood was going to my digestive tract than my muscles and brain. I felt drowsy. I’ve learned a lot since then. I won’t be carrying protein powder with me on this thru-hike. I will be eating things like dehydrated hummus, refried beans, cliff bars, Probars, walnuts and chia seeds, spread throughout the day. A big meal at night will help with general recovery while I rest – but it’s not just the protein that does that. It’s the combination of macronutrients, micronutrients, antioxidants and bioactive compounds. It’s the whole meal, the whole food. The whole picture.
While it is true that protein plays an important role in maintaining vital body functions and initiating muscle recovery, it’s not the only factor. When we eat more food, we get more protein. Protein is everywhere.
1. Campbell, TC., Campbell, TM. The China Study: The Most Comprehensive Study of Nutrition Ever Conducted and the Startling Implications for Diet, Weight Loss and Long-term Health. Dallas, TX: BenBella, 2005. Print.
2. Gregger, M. Dr. Burkitt's F-Word Diet. http://nutritionfacts.org/video/dr-burkitts-f-word-diet/. Accessed April 17, 2014.
3. McDougall, J. "When Friends Ask: Where Do You Get Your Protein?". April 2007 Newsletter. http://www.drmcdougall.com/misc/2007nl/apr/protein.htm.
4. Campbell, TC. The Mystique of Protein and Its Implications. http://nutritionstudies.org/mystique-of-protein-implications/. Accessed April 22, 2014.
5. Wood EJ. Marks' basic medical biochemistry: A clinical approach (third edition). Biochem Mol Biol Educ. 2009; 38(7):722.
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