What you’ll learn here
Google ‘how much protein do I need,’ and you’ll find plenty of contradictory stands.
Some claim that you only need 0.8 grams of protein per kilogram of body weight per day. While others say you’d see the most benefits with 2 grams per kilogram. Tired of trying to make sense of all the conflicting information? We’ve got you covered.
Here’s the definitive, evidence-based (as always) guide on everything you need to know about protein.
What is protein? Why is it important?
Protein is one of the three major macronutrients that make up your diet. With the other two being fat and carbohydrate (1, 2). Here’s an article talking about macronutrients and micronutrients, if you’re keen to learn more.
It is found throughout your body – in muscle, bone, skin, hair, bone, and virtually every other body part or tissue.
Protein is made up of amino acids. For those unaware, that’s organic compounds made of carbon, hydrogen, nitrogen, oxygen, or sulfur. These amino acids join together to form long chains (aka protein).
There are 20 different kinds of amino acids. And the sequence in which these amino acids are arranged helps determine the role of that particular protein.
Struggling with the concept? You can simply think of protein as a string of beads, where each bead is an amino acid.
Due to the sheer number of possibilities in which these different ‘beads’ can be arranged, there are at least 10,000 different proteins in your body that make you what you are and keep you that way.
Functions of protein
These proteins carry out crucial functions in your body, such as:
- Promoting growth and maintenance of tissues (3, 4, 5, 6, 7, 8)
- Catalyzing bodily functions (enzymes) (9, 10)
- Transmitting information between cells, organs, and tissues (hormones) (11, 12)
- Providing your body with structure, strength, and elasticity (13, 14)
- Maintaining healthy pH values of your bodily fluids (15, 16)
- Protecting your body from foreign invaders (antibodies) (17, 18)
- Transporting nutrients throughout your entire body (19, 20, 21)
- Serving as an energy source when your body is low on calories or carbs and fat (22, 23)
Now, unlike extra fat (which we can store very easily around our hips and bellies), we don’t store lots of excess amino acids. Our body is always using, recycling, and excreting protein.
So, if you don’t get enough protein in your diet, you run the risk of missing out on those vital functions.
Over time, that could lead to health issues, such as a loss of muscle mass, weakened functioning of the heart, and even premature death (24). Yikes!
- Protein is one of the three major macronutrients and is found in virtually every part of your body.
- Amino acids – 20 different kinds of them – are the building blocks of protein.
- Different types of proteins carry out bodily functions that are vital to your survival.
- As we don’t store lots of excess amino acids, we need to replenish them through eating protein to avoid running into health issues in the long-term.
Should I care about ‘complete’ and ‘incomplete’ proteins?
Protein can be further divided into two categories: complete and incomplete, based on its chemical structure.
Now, time for a pop quiz. How many amino acids are there in the body? You’d know if you were paying attention! As mentioned earlier, there are 20 different amino acids.
Difference between complete and incomplete proteins
Here’s something more to know. Of these amino acids, 11 are non-essential, or those our body can synthesize, and 9 are essential, or those we cannot make and need to get from food.
Here’s a list of 9 essential amino acids we can only get from the protein in our diets: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
If you’re familiar with workout supplements containing BCAAs, they typically include 3 of the essential amino acids: leucine, isoleucine and valine. It may seem like a good idea, but the truth is: supplementing with BCAAs isn’t effective.
So, complete proteins are simply foods that have all nine essential amino acids that our bodies cannot naturally make. Whereas incomplete sources may have a few of the nine – but not all of them (25).
Generally, animal protein – beef, chicken, fish, turkey, pork, and dairy – is complete. While plant protein – nuts, seeds, rice, beans, and grains – is incomplete.
There are some exceptions, though.
Bucking the trend, for example, are soy, quinoa, and buckwheat, which are all plant sources of complete protein.
What if I don’t eat animal products?
Now, if you’re someone who doesn’t eat animal products, you may be getting worried.
Does this mean you have to track the amount of specific essential amino acids you’re getting from various plant-based sources?
Well, thankfully, no. Honestly, you can put that Excel sheet away.
If you get a variety of protein throughout the day and not limit yourself to only one plant source, you probably don’t need to get too hung up about which amino acids you’re getting (26).
What’s more, there are plenty of plant-based protein powders that could be used to supplement your diet.
Nonetheless, you may still want to keep an eye on your overall protein intake level. That’s because of the lower amount of protein content in plant-based foods.
That’s because plant-based proteins are typically inferior to animal-based proteins when it comes to both bioavailability and amino acid profile. And that brings us to the next part.
- Of the 20 different kinds of amino acids, 11 are non-essential, and the rest is essential.
- Our bodies cannot make essential amino acids, so we have to get them through our diets.
- Protein can be further categorized into two: complete and incomplete.
- Complete protein sources are foods that have all nine essential amino acids. Incomplete protein foods only have a few of the nine.
- Animal proteins tend to be complete, while plant proteins are typically incomplete.
- For people who don’t eat animal-based products: you don’t need to track amino acid intake if you’re eating a wide variety of plant-based proteins.
How much protein do I need a day?
You’re probably screaming at your computer screen, “Just tell me what my daily protein intake should be!”
Calm down. You’re going to get specific numbers in just a bit.
For adults, the US Recommended Dietary Allowance (RDA) for protein is 0.8 gram per kilogram body weight (27). So – case closed, right?
Multiply your weight by 0.8, and that’s the amount of protein (in grams) you should eat, right? No. Not at all.
See, that figure represents the minimum intake needed to prevent malnutrition. This amount is only sufficient for preventing protein deficiency. That’s wildly different from optimal functioning (28)!
What does this mean for you then?
General protein intake guidelines
Thankfully, the folks over at Examine.com have come up with a well-researched piece you can refer to (29).
Here’s the gist of it if you’re short on time:
- Overweight or obese: 1.2–1.5 grams per kilogram body weight
- A healthy weight, active, and trying to lose weight: 1.8-2.7 grams per kilogram body weight
- A healthy weight, active, and trying to gain muscle: 1.4-2.4 grams per kilogram of body weight
- Experienced lifter on a bulk: 3.3 grams per kilogram body weight
Admittedly, the range can be intimidating. So, if you’re stuck in a choice paralysis, here are some general, daily numbers you can start with:
- If you’re active: 2.2 grams per kilogram body weight
- If you’re sedentary: 1.6 grams per kilogram body weight
These are, of course, not magic numbers. You should still experiment with them. See how you feel and how your body changes based on your intake.
And the easiest way to more accurately estimate your intake is through meal prep where you have better control over your food portions. Even just doing it for 1 to 2 days a week is useful. If you’re interested, here’s a useful guide on meal prepping.
- While the US RDA recommends 0.8 grams of protein per kilogram of body weight, that’s really the minimum amount needed for survival.
- How much protein a woman needs to eat is ultimately determined by her body type, activity level, and fitness goals.
- Even with the provided recommended protein intake numbers, you should monitor how you feel and perform. Tweaking may be necessary.
Is there a limit to how much protein your body can absorb?
Excellent. You now have the answer to ‘How much protein do I need a day?’
But here comes an important question: have you ever whipped up a perfectly medium-rare, thick, juicy steak, only to have someone shoot you down with, “That’s such a waste of food – your body can only absorb 30 grams at a time.”?
Well, you would be pleased to know that that’s simply not true.
This misconception probably stems from two separate facts. First, the rate of protein uptake on an hourly basis fluctuates between 5 to 10 grams per hour. And second, we typically eat every 3 to 4 hours (30, 31, 32).
But that doesn’t mean that your body just passes out the ‘excess’!
The truth is that amino acids and some peptides can self-regulate their time in the intestines – even if your body doesn’t need them at the moment.
Think of your small intestines as a ‘free amino acid pool’ that your body can draw amino acids from on an as-needed basis (33, 34).
Ultimately, as your small intestine will tend to slow down protein absorption, it seems that you can consume a fair amount of the macronutrient in one sitting. That’s assuming you don’t get too full – of course.
Research agrees that there’s no limit
Not convinced? Well, here are several studies on the matter:
- In a study performed on women, the intake of more than 54 grams of protein in a single meal versus across four meals resulted in the same level of protein retention (35).
- The consumption of 80 to 100 grams of protein in a small 4-hour window by intermittent fasters did not result in lower levels of lean mass (36, 37).
Simply put, the amount of protein you consume in a day is more important than how spread-out your intake over the day is.
Don’t stuff your face with protein
Here’s a disclaimer.
I know there will be a couple of you who are going to take this advice to the extreme – and gorge yourself. If 2 grams of protein per kilogram of body weight is better than 0.8 grams of protein per kilogram of body weight for muscle growth … then, 5 grams must be even better, right?
It doesn’t work that way. Unfortunately.
There’s no clear benefit of going beyond 2.2 grams of protein per kilogram of body weight for most of us. This is especially since eating more protein will undoubtedly impact your ability to stay within your ‘calorie budget’.
And, not to mention, negatively impact your intake of other crucial macronutrients (i.e. carbohydrates and fats).
- Your body doesn’t just pass out the excess protein you eat; amino acids are stored in your small intestines, ready to be used on an as-needed basis.
- You can consume a fair amount of protein in one sitting without worrying about it going to ‘waste’.
- However, that doesn’t mean you should eat protein with reckless abandon. There’s no clear benefit to exceeding 2.2 grams of protein per kilogram of body weight for most of us.
Does protein intake timing matter?
What about intake timing?
There must be a reason why everyone rushes to chug their shakes the moment they’re done with their workouts, right?
Well, unfortunately, those people have bought into the myth of the anabolic window.
Just so everyone is on the same page, the anabolic window here refers to the alleged 30-minute period after a workout where your body is particularly primed to accept essential nutrients and shuttle them into building lean tissue mass.
Does the anabolic window really exist?
Here’s the thing, though. Research doesn’t support this hypothesis.
The prompt ingestion of proteins after a lifting session has not been shown to influence the rate of muscle protein synthesis (MPS) at all (38)!
The intake of protein at either 1 hour or 3 hours after exercise resulted in the same level of MPS (39). Yes – the same level!
Nonetheless, that does not mean that the anabolic window doesn’t exist. It does. Only, it’s more extended than commonly thought.
But just how extended?
Well, research suggests that the anabolic window may turn out to be as long as 4 to 6 hours around a training session, depending on the size and composition of the meal (40).
As with before, the most crucial thing you need to do is to hit your daily protein requirements by adequately spacing them out evenly with a minimum of 4 meals a day.
But – why do you need to space your meals out? Well, because:
- Practicality: Protein is highly satiating. You may even find yourself struggling to finish those last few bites of your meal!
- Muscle growth: Research shows that spacing your protein intake out (minimum of 4 meals) gives better muscle growth results than squeezing your daily requirements within 2 meals (41).
You don’t have to sprint to your locker after your last set of hip thrusts, then cry when you realize you’ve left your shaker at home.
There’s plenty of time for you to get your protein in.
Of course, protein shakes are an excellent way to help you meet you daily protein requirements. If you’re interested, here’s an article comparing different protein powder types and which ones you should choose.
- Many people mistakenly believe in the concept of a 30-minute anabolic window period, where the body is primed to shuttle nutrients into building lean tissue mass.
- The truth is that the anabolic window exists, but it lasts for much longer than 30 minutes. Research suggests that it may be as long as 4 to 6 hours.
- Instead of caring about when you’re getting your protein in, the most crucial thing to focus on is in hitting your daily intake requirements.
Is too much protein dangerous?
If you’ve been keeping up with news, you must have noticed that there have been various suggestions that consuming too much protein can be harmful to your health.
The claims against protein are both numerous and varied. For example, too much of it gives you cancer, destroys your kidneys, and causes heart disease.
But are those claims true? And perhaps more importantly, how do we know how much ‘too much’ is?
Protein and kidney damage
This is probably the most common danger that many people think of when it comes to high-protein diets.
Even some (misinformed) doctors would tell you that!
Thankfully, this topic has been researched pretty extensively, and there is no evidence that high-protein diets contribute to the failure of normal, healthy kidneys (42, 43, 44, 45, 46).
Furthermore, there is some evidence that suggests that higher protein intake might contribute positively to kidney functioning (47)!
Protein and heart disease
Diets that are higher in meat (and especially red meat) have long been linked with a higher risk of developing heart disease.
And somewhere along the line, protein took on this associative connection.
But think about it: just because diets high in red meat are linked to heart disease, and that red meat contains lots of protein, doesn’t mean that it is linked to heart disease!
Also, other studies have shown that leaner cuts of red meat don’t negatively impact the risk of developing heart disease – thereby suggesting that it may be the fat content at fault rather than red meat itself (48).
Protein and cancer
Admittedly, on a population-wide basis, there’s a link between red meat and cancer.
The association has been shown numerous times but is relatively weak in relevance.
Also, the truth is that people who consume more red meat also tend to eat more calories overall and have a higher BMI, eat fewer fruits and vegetables, and have higher rates of smoking and alcohol consumption (49, 50).
All these are also risk factors.
Therefore, it cannot be concluded that red meat causes cancer – an association is not causality, after all.
There is no solid evidence that too much protein can cause health issues like kidney damage, heart disease, and cancer.
Takeaway: how much protein do I need?
Hopefully, you now see that the various health risks often associated with protein-rich diets don’t seem to hold water.
So, it appears that you don’t need to worry about excessive protein consumption. There isn’t a consensus on an absolute limit for its intake.
And with protein’s importance, it’s definitely clear why protein powder is one of (only) three workout supplements that are proven to work.
All in all, when it comes to the amount of protein you need, it all depends on how much you need for your fitness goals.