When it comes to literally anything related to nutrition, protein seems to be at the forefront of many people’s minds. When it comes to fitness and performance nutrition, it’s not a matter of if, but when, protein becomes a part of the discussion. While there are 3 different macronutrients (i.e. “macros”), carbohydrates, proteins, and fats, it seems as though protein gets a disproportionate amount of attention. Today, I’d like to clear the air related to some of the common misconceptions I hear regarding protein. Along the way, I’d like to make the argument that this macro isn’t any more important than carbs or fat, regardless of your health and fitness goals.
That being said, let’s get started…
Myth #1: Eating more protein means building more muscle
This is possibly the most common mistake I see, particularly among the weightlifting community. The thought-process behind this is actually quite logical: muscles are damaged during exercise… muscles are made of protein… protein is needed to help repair muscles… thus, MORE protein will repair muscles BETTER and FASTER. Unfortunately, this simply isn’t the case. Our body can only rebuild muscle as fast as it is genetically programmed to. Providing adequate protein is obviously important so that the rebuilding of muscle can occur, but extra protein does nothing to help the process. For example, imagine you are the boss of a team of construction workers building a house. You can continue buying and stockpiling all the supplies you want to build the house, but your workers can only build this house so fast. The exact same is true for muscle.
To take this argument one step further, I would argue that overdoing it on protein intake can actually hinder muscle-building and other fitness goals. Protein is a highly-satiating macronutrient. In other words, foods that are high in protein are typically very filling. With this, a protein that is very high in protein will crowd out other foods that carry other important nutrients, leaving you too full to consume a balanced meal. While a balanced diet filled with vitamins and minerals is essential to performance and recovery, the main nutrient that I see get left out in favor of protein is carbs. When you fill up on protein and don’t take in enough carbs, your energy levels are going to suffer. If you get in the habit of under-fueling for your workouts, you aren’t going to be truly pushing your limits and actually experiencing any kind of genuine progress. It may not be a surprise to hear, but a diet that balances all nutrients without prioritizing one over the others is going to yield the best results for performance and overall health.
Myth #2: Too much protein is bad for your kidneys
This misconception seems to take the polar-opposite stance to the first. Instead of trying to get more protein in, I hear some people share that “too much protein is bad for your kidneys”. A quick Google search using terms like “kidney function” or “kidney disease” and “high protein diet” will yield a variety of results that seem to say that high-protein intake is detrimental to kidney function. What’s more, these results have connecting links to peer-reviewed, scientific, sound research. Based on these results, it is very easy to conclude that too much protein will wreak havoc on your kidneys. Rest assured, this is also not the case.
As a dietitian, I’m rather defensive about definitive recommendations related to diet and health. In this case, making conclusions based on Dr. Google’s quick search results undermines the work and experience needed to truly read, understand, and implement research. In this case, many of the studies that populate in this sort of search are referring to individuals with kidney function that is already compromised. In other words, it is true that high-protein intake can be detrimental to kidney function, but only those with kidneys that already don’t work properly. I feel this study by Martin et al., 2005, says it quite well: “Although high protein diets cause changes in renal function (i.e., increased GFR) and several related endocrine factors that may be harmful to individuals with renal disease there is not sufficient research to extend these findings to healthy individuals with normal renal function at this time.” To wrap up this myth-busting, you have nothing to worry about when it comes to eating protein so long as your kidneys are healthy.
Myth #3: Protein from animal sources is superior to plant sources
This argument has some pseudoscience roots that makes it seem like a rather strong point. The basis of this myth comes down to the difference between “complete” versus “incomplete” proteins. Complete proteins are proteins that have all essential amino acids, or amino acids that our body needs to function but cannot make on its own. On the other hand, incomplete proteins are proteins that are missing one or more essential amino acid. Animal sources (e.g. eggs, meat, dairy, etc.) of protein are considered complete, while plant sources of protein are considered “incomplete” (with a few exceptions, such as quinoa). The important distinction here is that our body is able to convert some amino acids into other amino acids, based on what it most needs, but it is only able to do this with non-essential amino acids. For example, your body can convert alanine (a non-essential amino acid) into glutamine (another non-essential amino acid). What your body CAN’T do, is convert something like alanine (a non-essential amino acid) into tryptophan (an essential amino acid). In this case, you must get tryptophan in the diet. From this understanding, the animal protein source, containing all essential amino acids, is always superior to the plant-based protein.
While the perspective of this argument is logical, it is a very reductive perspective when nutrition should also focus on “bigger picture”. In this case, this ignores all other nutrients within the food supplying the protein. In other words, a steak will provide high levels of protein, but it is usually high in saturated fat, relatively high in cholesterol, and low in fiber and vitamins and mineral. On the other hand, plant sources of protein, like black beans, are high in fiber, vitamins, and minerals while also delivering next to no fat or cholesterol. If you’re concerned about getting all essential amino acids, you can rest assured knowing that having variety of protein sources throughout the day (e.g. oatmeal with breakfast, rice with lunch, beans with dinner) will meet, if not exceed, all essential amino acids you need in a day. With that, you can feel confident about meeting your protein needs whether its from animal or plant sources (or ideally, a mix of both!) as long as there’s variety.
Myth #4: A high-protein diet is the key to successful weight-loss
This myth also has some roots in truth, but unfortunately it is often misconstrued and taken to extremes. As I shared under Myth #1, protein is a highly-satiating nutrient. Eating protein helps aid with feelings of fullness. If you’ve ever eaten a big helping of beans, eggs, or steak, you might agree. With this understanding, the perspective for weight loss is often to eat as much protein as possible to stay full as long as possible while eating as little as possible. While this is logical, it is again missing the “bigger picture” of nutrition. First, refresh yourself on why eating too much protein is counterproductive for fitness goals by reading my debunking of Myth #1. In short, excessive protein intake means deficient intake of something else. It could be carbs, fats, vitamins… take your pick. If you have a weight loss or body composition goal, you need to provide your body with the healthiest, most balanced diet possible. If your diet is not balanced or sustainable, you’re going to quit on whatever changes you’ve made. Further, weight loss is much more complicated than “calories in, calories out”, and you can’t just “cheat the system” by eating a diet heavy is one nutrient while lacking in others. Weight loss is a subject much too complicated to be distilled into a couple short sentences. Suffice to say, any diet that requires you to take in high levels of something while restricting something else is guaranteed to be unsustainable and will, eventually, fail.
If you want to be your healthiest and happiest self, find a dietary balance of nutrients that nourish your body while satisfying your cravings. If you don’t know how to find this balance, talk to a licensed or certified health or nutrition professional.
Myth #5: Your body can only use a certain amount of protein in one sitting, anything more is wasted
This myth is my favorite to debunk, as it assumes that the body is “incapable” of using food you give it. To bust this myth simply, your body does not waste any food you eat. Regardless of how much protein you eat in one sitting, your body will metabolize it all and find some way to use it. I do believe that this is sometimes thought in the context of whether the protein will be used for muscle-building or “wasted” by being used by the body for something else. When it comes to eating more protein and whether it will help build more muscle, you can refer to Myth #1. In addition to overdoing the protein daily, it is possible to take in more protein than is helpful for muscle growth in one sitting. Will the extra protein be harmful? Not necessarily. It simply won’t speed up your recovery any faster after reaching a certain threshold. Beyond the threshold of protein needed for repairing muscles, the remaining protein will mostly be burned for energy. With a much greater excess beyond use for muscle-repair and energy-production, some protein might be converted and stored as fat for energy later on. With that answer, most people want to know, “So what is that threshold? How much protein should I have in one sitting for the best recovery without going over?” To give you the most honest and accurate answer anyone could possibly give: I don’t know. That’s the unfortunate truth. I don’t know because nutrition recommendations can’t be made as generalizations. Every body and lifestyle is too diverse to be making nutrition prescriptions in a public blog. If there is a public article claiming exact numbers for how much of anything you need nutritionally, they’re making grave generalizations and are definitely not accurate for your individual needs.
With that, allow me to climb down off my soapbox and give you an answer that might be helpful in some way. Now that I’ve established that I don’t actually know how much protein your body needs and that generalizations aren’t accurate… allow me to make a generalization. Based on research of averages of body weights and body sizes, it seems that 20-30g of protein, depending on how large your body is and how active you are, seems to be the ideal range for optimizing protein use for muscle-protein synthesis (or building and repair). In addition, the metabolic and recovery benefits of consuming this amount of protein after a workout is enhanced when also eaten with carbs.2 This range of protein can apply to meals or snacks throughout the day, as well as after workouts. Note that despite using averages and making a generalization, it is still a range. My hope is that these numbers help you at least make ballpark estimates when it comes to nutritional planning.
Busting nutrition myths takes a lot of “bigger picture” views because understanding our body requires a “bigger picture” perspective. When it comes to health, fitness, and nutrition, it is easy to get caught up in the details and nuances while forgetting our fundamentals. While some of the info I might be sharing is not earth-shattering, it is based in fact and proven itself for many, many years.
Our bodies are incredibly efficient and incredibly resourceful. The body is not wasteful. Years of our ancestors surviving famines and droughts has taught our body that any food that comes in is more valuable than gold. Further, our bodies are much, much smarter than we are. Years of research on the human body has turned up as many (if not more) questions as it has answers. This fact remains, there really isn’t a diet we can choose that will “outsmart our biology”. Recent years have shown a dramatic uptick in extreme diets, choosing to cut out entire food groups or revert to extreme restriction. Whatever diet you may think of, it simply can’t account for all that isn’t known about the human body and nutrition. Every day, research discovers something new about the human body. Every year, dramatic progress is made in nutritional research and developments. Despite every major discovery made from year-to-year, one truth remains: The body functions best with a balanced diet rich in a wide variety of food, including foods from plant and animal sources.