Most people are familiar with the benefits of protein. It provides the necessary building blocks our bodies need to grow and heal. If you’re not getting enough, the body will actually start to break down your own tissues, leading to a host of health issues. But how much do we really need and what are the best sources?
What's the RDA for protein?
Most sources state that women need only 46 grams and men need 56 grams of protein per day. Let me explain why these numbers are actually way too low.
The recommendation of 0.8 grams of protein per pound of body weight and is based on nitrogen balance, meaning you’ve reached the right amount of protein you’re at "zero nitrogen balance." The problem is, this is difficult to measure, varies greatly between individuals, and can lead to underestimations of true protein requirements.
While many people like to think that the protein RDA is the average amount needed for most healthy people, in reality 0.8g/kg is the minimum amount of protein required to avoid loss of lean muscle mass—not the optimal amount for health.
Worse yet, because most folks aren’t going to make the calculation of their weight in kg multiplied by 0.8, the government made it easy for us by translating the RDA based on a "reference" woman of 57 kg (125 pounds) and a "reference" man of 70 kg (154 pounds), which equals 46g and 54g respectively. But if you stop to think about it, how many people do you know who actually weigh this little?
The average American man is actually 88.6kg (195 pounds) and the average woman is 76 kg (166.2 pounds), according to the CDC. If we use the 0.8g/kg protein recommendation for average weights, the RDA shoots up to 60g for women and 71g for men. But again, this is the minimum amount of protein to avoid muscle loss, not the amount to consume for optimal health.
So, what's the ideal amount of protein for good health?
Another set of recommendations are the Acceptable Macronutrient Distribution Range (AMDR), which are defined as, "a range of intakes for a particular energy source that is associated with reduced risk of chronic diseases while providing adequate intakes of essential nutrients." The recommendation for protein intake according to the AMDR is 10 percent—35 percent of caloric intake. As a dietitian, I like to start my patients off at a middle ground of about 20 percent of calories from protein. This means for someone eating 2,000 calories a day, in order to get 20 percent of their calories from protein, they should be eating 100g. That’s double the common dietary advice!
Why should you consider eating more protein?
One of the biggest bonuses of consuming more protein is that it fills you up and helps you lose weight. This is because protein is the most satiating macronutrient.
In one study, participants who increased their protein from 15 percent (the average American’s intake) to 30 percent of total calories naturally reduced their overall caloric intake and saw significant weight loss. Another study showed that high protein intake reduced LDL (bad) cholesterol and reduce abdominal fat. In those with type 2 diabetes, high-protein diets (25 percent—32 percent of caloric intake) led to weight loss and lower blood pressure and HbA1C levels, the long-term measure of blood sugar. High-protein diets have also been shown to be beneficial for bone health. Eating too little can lead to fatigue, weight gain, and hair loss.
Can you eat too much protein?
One study of an Eskimo population in 1855 found that when they were eating an "all meat" diet, their protein intake was only 44 percent due to high fat intake. During times of plenty, they would consume 4 to 8 pounds of meat a day, with a daily average intake of about 280g of protein and 135g of fat. Early American explorers survived for extended periods of time only on pemmican, a food made of dried lean meat mixed with fat, with a protein content of 20 to 35 percent.
What about the concerns that protein causes kidney disease and cancer? In healthy people, no danger has been found in protein intakes above 3g/kg. It’s true that those with kidney disease should limit their protein intake, but there’s no proof that increasing your protein intake actually causes kidney disease.
The studies linking protein to cancer are only able to show correlations, not cause. Just because eating something is associated with an outcome, doesn’t mean that particular food is necessarily what caused the problem. Most of these studies are looking at people on a Western diet vs. vegetarians. The typical American has a very different lifestyle than a typical vegetarian. Vegetarians are much less likely to smoke, drink, and much more likely to exercise. They also tend to eat less processed foods and sugar. So, saying that meat is the only factor causing of disease is flawed logic. In fact, a study that looked at people who shopped at health food stores (so, accounting for lifestyle factors) found no difference in mortality between vegetarians and omnivores. And when adjusting for confounding factors (i.e. lifestyle) a recent, very large study found "no significant difference in all-cause mortality for vegetarians versus non-vegetarians."
But aren't Americans eating way too much meat?
The short answer is, no. Since 1970, our intake of beef has declined from 2.7oz per day to 1.7oz per day, while our poultry intake has doubled. We’ve increased our intake of caloric sweeteners and our intake of grain products has gone up about 30 percent. We’ve tripled our intake of vegetable oils. Our actual intake of animal proteins is only about 5.6oz per day. Instead of blaming meat for our heart disease and skyrocketing diabetes, it’s pretty clear that what’s increased is our consumption of processed grains, sugar and vegetable oils. Our bodies are starving for more protein; yet when we eat lower protein diets, we simply eat more calories.
Since increasing your protein intake could help you lose weight, keep you full, and won't kill you, maybe it's time to try eating some more, and see how it feels in your body.
Want to get started? Here are the best whole food plant-based protein sources, and here are the best protein powders. Plus, a protein-packed salmon dinner to make you salivate!