How Much Protein Do We Need? RDA vs. Dietary Guidelines


How Much Protein Do We Need? RDA vs. Dietary Guidelines

Imagine running into a friend at the gym who was just finishing their aerobic workout. Sweaty and flushed, the person remarks as they down a bottle of water “Got to get my hydrogen!” While we may instinctively sense that there is something odd about that statement, in Western countries, and particularly the US, people make very similar comments on a regular basis. “Just getting my protein in!” someone will cheerfully report as they dig into General Tso’s chicken or crack open a hard-boiled egg. “I just make sure to eat lots of legumes” a vegan will say in response to the question of how they get enough protein without eating animal products.

This misguided preoccupation with one individual macronutrient has a long history in our culture, as Dr. T. Colin Campbell has documented in his own writing, in The China Study, in his book Whole, and in the online courses offered by the T. Colin Campbell Center for Nutrition Studies. Protein is vital for human consumption, but in no way can its importance be separated from the context of the whole food it came from. What we need to be consuming is food – whole, plant-based food–because it is whole, plant-based foods that provide the range of nutrients (protein included) that humans need to function in health.

That being said, we know you’re asking anyway: “How much protein do I really need?” There is an average minimum protein requirement for humans, and in the US it is called the Estimated Average Requirement – EAR. This number represents the average amount of protein an individual needs in a day, but because it’s the average, that means about half of us actually need less than that, and about half of us actually need more. For adults, this average is about 4-5% of total calories per day. How did we get this number? Scientists have measured the protein consumption of different groups of people and tracked them to see if they display any symptoms of protein deficiency. They are then able to correlate any symptoms that arise with different amounts of protein people are consuming and figure out the threshold where we start to have symptoms of deficiency.

Because half of us actually need more protein than that average minimum, the USDA Recommended Dietary Allowance for protein – the RDA – includes a buffer and suggests getting 8-10% of calories from protein. At that point, almost everybody (98% in fact) will be getting more than what they need. Check out page 4 of this document from the Institute of Medicine to learn more:

You’ll probably recognize the range that the USDA Dietary Guidelines are based on (the AMDR – adequate macronutrient distribution range). For protein that is 10-35%. How did it get so high? Well, those guidelines are using the RDA, the recommended minimum, as the bottom number of this recommended range – 10%. Remember that we have no evidence that anyone actually needs more than the minimum, in fact we have quite a bit of evidence that when we consume more than 10% protein, especially when including animal foods, we start to see increased rates of chronic disease.

Conveniently, eating a varied whole food, plant-based diet will naturally provide approximately 10% of protein from total calories. In developed countries we have the privilege of access to fresh, good quality plant foods at all times of year, and the variety available provides more than enough protein in the diet.

Want to test it out on yourself? Use the SuperTracker tool from the USDA to track the nutrient profile of your diet. You can create an account and track your diet over time, or just one day. Create a profile here. Then click on “Food Tracker” and enter foods you’ve eaten for each meal and snacks. You may need to separate some of your meals out into separate ingredients. Once you’ve finished entering all the foods you’ve eaten in one day, click the small link on the right labeled “Nutrient Intake Report”. This will show you a report with the nutrient contents of your entire diet! Of course, it may not be 100% accurate if you chose “stuffed pepper” as I did, and the system assumes it was made with a ton of salt! But it probably contains most of the foods you are eating.

So what were my results? Consuming in one day: oatmeal with banana and 1 TB of maple syrup for breakfast, an apple, carrot, and crackers and hummus for snacks, whole wheat noodles with kale, tomato sauce and white beans for lunch, a big salad (4 cups) with carrots, tomato, avocado and balsamic vinegar, a stuffed pepper, and broccoli for dinner, and a baked apple for dessert, I ate a total of 1950 calories, 11% of which were from protein. Not bad! And not too hard either, I did all this without thinking about anything except making sure I remembered to bring my lunch to work with me.

This article is reprinted from the Plant-Based Nutrition Certificate.

Micaela Karlsen is a PhD candidate in Nutritional Epidemiology at the Tufts Friedman School of Nutrition Science and Policy. Micaela received her master’s degree in human nutrition and public health from Johns Hopkins Bloomberg School of Public Health and has a BA in psychology from Cornell University. She is the author of A Plant-Based Life She formerly served as executive director of the T. Colin Campbell Foundation. Micaela founded the website, an online database of peer-reviewed research relevant to plant-based nutrition.
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