But Where Do I Get My Protein?
When I recommend to a patient that they move to a more plant-based diet, the question that almost automatically follows is: But where will I get my protein from?
These days, protein intake has become one of the most popular topics on podcasts, YouTube and social media. Everyone is talking about maximizing protein intake to build muscle, prevent “sarcopenia” and promote healthy aging. This is big business: The protein ingredients market is worth $60 billion dollars now, and is projected to increase to >$100 billion in just a few years.
But there’s not a lot of discussion about where to get the protein from. Everyone just seems to assume that you have to eat meat to get protein.
This just simply isn’t true, and is just a reflection of our biases in our “western” society. In fact, in 2013, the Journal of the Academy of Nutrition and Dietetics published the largest study to date comparing the nutrient intake of more than 71,000 non-vegetarians, vegetarians, and vegans. The study found that, on average, vegetarians and vegans get 70 percent more protein than they need every day (>70 grams).
So while getting enough really is NOT an issue, it makes sense to spend a few minutes learning about protein: How much do we really need, and where should we aim to get it from.
How much protein do we need?
The current Recommended Daily Allowance is 0.8 grams/kg of body weight per day. Most research and guidelines suggest that adults require no more than 0.8 or 0.9 grams of protein per healthy kilogram of body weight per day (the key is “healthy body weight”, so this calculation should be based on your IDEAL weight, not your current weight).
Can you eat too little? In this country, unless you have severe food insecurity and aren’t able to access food, you really don’t have to worry about not getting enough protein. As one group of researchers in this field said “Virtually everyone in western populations consumes more than their individual requirement”.
But do the podcasters have a point? Yes and no. It is certainly true that we tend to lose muscle mass as we age, and that people who take in more protein will lose less muscle mass. The Healthy ABC study showed that participants (>70 yrs old) who ate 1.2 g/kg per day of protein lost significantly less muscle mass (43% less, in fact) over the years as those who only ate 0.8 g/kg per day. But this was only 1.2g/kg per day, and not the 1g/pound per day that some influencers are recommending. We’re still not talking about making it your mission to force protein into your system all day long. And in this study, protein intakes were not associated with changes in muscle mass in participants who maintained weight. Only people who lost weight over time benefited from increased protein intake. Other studies, here and here have also shown that people consuming up to 1.0 -1.2 g/kg per day lose less muscle than people consuming less than this. A meta-analysis of 49 studies showed that while dietary protein supplementation significantly increased muscle mass development, supplementation beyond 1.6 g/kg per day resulted in no additional benefit. Here is a nice review of the topic, focusing on body-builders (who theoretically would need the MOST protein).
So while losing muscle mass as we age is a real concern, the research is really mixed as to the importance of protein intake as the only cause. Other research has suggested that it’s not even protein at all, and have pointed to physical inactivity, or muscle ‘disuse’, as maybe the most important mechanism underlying muscle loss in the elderly. Regardless, the groups that eat more protein and lose less muscle are still not consuming anywhere NEAR what the influencers are currently telling us to force-feed ourselves. The majority of research studies suggest a target of 1.2g/kg per day., or roughly 0.5g per pound.
OK, but what if the podcasters are really convincing? Maybe it would be safer to just eat a ton of protein in case they are right. After all, protein is good, right? You can’t have too much of a good thing, right?
Well, in short, you can: Long-term high protein diets may lead to worse health, causing disorders of bone and calcium balance, kidney problems, increased cancer risk, liver problems, and worsening of heart disease. And of course, it matters where you get your protein from: In people with heart disease or heart disease risk factors, a higher consumption of animal protein was associated with a 60% increased risk of fatal and non-fatal outcomes (when protein substituted for carbohydrates or fat).
How much should we aim for? An easy way to figure out roughly how much you should have is to take half of your ideal weight in pounds. So, someone whose ideal weight is 200 pounds would require 100 grams of protein a day. This simple calculation gets you to 1.1 g/kg per day.
OK, so that’s how MUCH we should eat.
WHERE do we find the best sources of protein?
While it is true that chicken (26 grams/3 oz serving) and steak (25g/ 3 oz serving) have a lot of protein per serving, beans (15 grams/ 1 cup) and lentils (18g / 1 cup) not only have a healthy amount of protein, but they are also rich in fiber, vitamins, and minerals.
Plant sources of protein are also definitively lower in saturated fat, have no cholesterol, and are high in fiber, phytonutrients and antioxidants. And by the way, fiber is crucially important to human health, reducing the risk of cancer, heart disease and premature death. (How much fiber is in Steak? Chicken? Pork? Fish? None).
As a result, consumption of vegetable protein sources is associated with better health outcomes overall (and specifically on the cardiovascular system) than animal-based sources.
There is a wealth of research over the last few decades that has shown that plant sources of protein are healthier for humans. In a meta-analysis from the Atherosclerosis Risk in Communities study (432,179 participants), when carbs were decreased in exchange for animal fat/protein, the risk of dying INCREASED by 18%! But of course mortality risk DECREASED by 18% when the substitutions were plant-based.
Another research study from 2021 with a total of ~1.5 million subjects revealed consistent and significant benefits of substituting plant protein for various animal proteins on all-cause mortality. As plant protein intake went up, mortality went down: they calculated a 44% decline in rates dying from any cause! The largest benefit occurred when getting rid of protein from red and/or processed meat, and replacing that with protein from plant sources.
In 2016, a Harvard study reviewed protein intakes of more than 131,000 women and men from the Nurses’ Health Study and Health Professionals Follow-up Study. After tracking their diets for up to 32 years, the authors found that replacing animal protein with plant protein was associated with lower risk of dying prematurely. The biggest offender again was processed meat like bacon. Swapping in even just 3 percent plant protein for any of the animal proteins was associated with a significantly lower risk of death.
And the large NIH-AARP study of 400,000 people also showed that swapping 3 percent of calories from various animal protein sources with plant protein was associated with a 10% decrease in overall mortality.
Some may read these results and worry about how many beans they have to eat to get the health benefit. Well, many of the studies above showed health benefits with just a measly 3% substitution.
How much is 3%? Well, in an average american diet, that is approximately 60 calories, or 15g of protein. A cup of black beans has roughly 15g of protein; a single serving of steak (3 oz portion) of steak has ~25g of protein. So substituting out roughly half of that steak for a cup of beans would lead to significant long term health benefits.
Of course, more dramatic changes in your diet will lead to more significant changes in your health, but even a change as little as a small portion of beans, lentils or soybeans can have a meaningful impact.
In summary, we really should worry less about how much protein we are getting, and worry more about WHERE we are getting it. Once again we learn that some small changes in our lifestyle can lead to dramatic changes in our health over the long term.
At Wisconsin Cardiology Associates, we counsel our patients to aim for a healthy, plant-based diet, emphasizing fruits, vegetables, beans, lentils, whole grains and nuts. Have questions about the best way you can prevent heart disease? Call us and make an appointment for a consultation.
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