Eating enough high quality protein is critical for looking and feeling your best.
This article is all about good sources of protein and how much you need.
If you have any questions after reading, let me know in the comments 🙂
What is protein?
A “protein” is a chain of amino acids.
Amino acids comprise a carbon, hydrogen, and oxygen backbone with an attached nitrogen-containing amino group.
Amino groups also, in some cases, include sulfur.
The word “protein” comes from the Greek word, ““proteios”, meaning prime or primary.
This is due to many considering protein the most fundamental component of tissues in animals and humans (1).
So, just what is it about protein that makes it so fundamental?
Why do we need protein?
First, let’s get a little nerdy, specifically with the roles amino acids in our health.
You might already know that we break protein down into amino acids to rebuild them into muscle and other tissues.
However, we use amino acids for a ridiculously long list of critical functions (2):
Building body tissues and structures
- Building blocks for proteins, large peptides, and small peptides
- Substrates for, and activation of, protein synthesis
- Recovery from injury
- Enhancement of wound healing after surgery or injury
- Synthesis of collagen and remodeling of extracellular matrix
Cellular signaling and genetic expression
- Regulation of gene expression, as well as micro-RNA biogenesis and levels
- Cell signaling via kinases, G protein-coupled receptors, and gaseous molecules
- RNA and DNA synthesis, as well as amino acid, heme, and carnitine synthesis
- Inhibition of autophagy and intracellular protein degradation
- One-carbon unit metabolism and methylation of DNA and protein
- Regulation of apoptosis and aging
Nutrient digestion and assimilation
- Nutrient transport and metabolism
- Transport of water, amino acids, protein, glucose, fatty acids, vitamins, and minerals
- Major energy substrates for the small intestine and immunocytes
- Regulation of glucose and long-chain fatty acid oxidation and synthesis
- Chemical sensing in the gastrointestinal tract
- Gastrointestinal emptying and the motility of the small intestine
- Conjugates with taurine and glycine to facilitate lipid digestion and absorption
- Modulation of growth, metabolism, and population of microbiota in the small intestine
- Activation of lipolysis and reduction in white adipose tissue
- Stimulation of brown adipose tissue development and thermogenesis
- Hormone secretion and endocrine status
- Synthesis and secretion of thyroid hormones, insulin, glucagon, and glucocorticoids
- Mediation of hormone actions
Immunity and anti-oxidation
- Modulation of immune responses and prevention of infectious disease
- Anti-oxidative defenses and removal of toxic substances
- Synthesis of glutathione, carnosine, creatine, and taurine
- Synthesis of antioxidative enzymes
- Removal of ammonia and xenobiotics
Neurological function and behavior
- Neuroprotective reactions
- Synthesis of neurotransmitters
- Agonists and co-agonists of N-methyl-D-aspartic acid
Miscellaneous other effects
- Regulation of blood flow and cardiovascular function
- Regulation of acid–base balance
- Pigmentation for skin, hair, and eyes
Aesthetics, health, and performance
That all being said, there are more immediate and tangible reasons you might want to eat more protein.
For example, eating more protein promotes higher metabolism, feeling more full, and losing more fat – not precious muscle, organs, or other tissue – when losing weight (3),
Furthermore, eating more protein might also help you build muscle and strength (4).
Moreover, a 2020 study showed an association between higher protein intake and less symptoms of depression (5).
Next let’s cover how to make sure you’re getting enough of the right kinds of protein in your diet.
What are good sources of protein?
Exact numbers might vary depending on who you ask, but we use around 21 unique amino acids, nine of which – termed “essential” – we must get from protein in our food (6).
Plants, animals, algae, and fungi can all serve as sources of dietary protein.
However, animal sources – like meat, dairy, fish, and eggs – have their advantages over other sources (7).
For starters, they typically offer more digestible, bio-available, and complete amino acid profiles than plant sources.
Additionally, they offer a variety of nutrients that aren’t found in plant sources.
These include heme-iron, cholecalciferol, docosahexaenoic acid (DHA), vitamin B12, creatine, taurine, carnosine, and conjugated linoleic acid (CLA).
Prioritizing animal foods can also help promote adequate calcium, vitamin D, potassium, iron, and folate intake (8).
Finally, you’ll probably find it much easier to hit your protein needs with animal foods, especially if prioritizing minimally-processed foods.
For instance, it might take around 200 calories’ worth of steak to get 30 grams of protein, whereas it would take over 800 calories’ worth of almonds to get that same 30 grams of protein (9).
That’s not even accounting for differences in amino acid quality or other nutrients.
That all being said, with some planning and maybe supplementation, you might do just fine with only plant sources.
How much protein do you need?
The recommended daily allowance for protein is 0.8 grams per kilogram (g/kg), or 0.36 grams per pound (g/lb.) of body weight, per day.
However, you might consider this more of a bare minimum than an optimal amount (10).
You’ll likely look, feel, and perform your best with the following daily targets from the International Society of Sports Nutrition (11):
- For building and maintaining muscle: a minimum of 1.4 – 2.0 g/kg (0.64 – 0.91 g/lb.)
- For retaining lean body mass during weight loss: up to 2.3 – 3.1 g/kg (1.0 – 1.4 g/lb.)
- You might even benefit from going higher than 3.0 g/kg (1.36 g/lb.)
Aiming for a middle ground of 1.0 gram per pound of body weight per day might be a simple, easy-to-remember starting point.
This usually equates to one or two palm-sized (4.0 – 8.0 oz.) servings of protein with each meal, three to four meals a day.
Of course, if you want to take a more detailed approach, that’s totally cool.
For example, you might want to calculate your specific requirements, and then measure and track your food intake to make sure you’re on target.
Find what works best for you.
How much protein can you use in a single meal?
There’s a perception that we can only digest somewhere around 40 grams of protein per meal.
However, this often-report limit is rarely discussed with the nuance it deserves (12).
This limit (which varies, depending on who you ask) is often based on what has been found to be “optimal” for muscle protein synthesis.
That is, it’s not necessarily a “limit” of how much one can eat in a single meal and still actually absorb.
Furthermore, this “optimal rate” is based on rapidly digesting protein sources eaten in isolation.
Eating less processed forms of protein and/or eating protein in a mixed meal would likely slow digestion, reducing the amount of amino acid oxidation.
Moreover, increased amino acid oxidation doesn’t mean that all amino acids above a specific level are oxidized.
It means that they are oxidized at a rate that is no longer optimal for muscle protein synthesis.
Recall, however, that muscle protein synthesis is only one effect of protein on the body.
Sure, we might not be optimally stimulating muscle protein synthesis.
However, we might still be using the amino acids it provides for all of the other processes they support.
What to do now
First, plan ahead.
Figure out what kinds of protein sources you think you might enjoy most.
From there, figure out when and how often you plan to grocery shop.
Next, list out how much of each kind of protein you might want to buy when you shop.
Make sure that you buy enough protein on each trip to hit your targets until the next trip.
Think also about how you might want to prepare your protein.
If you’re just getting started, you might want to keep things simple.
That is, consider sticking to basic cooking methods like baking, grilling, or sautéing at first.
Finally, experiment a bit to find what works best for you.
Pay attention to how different sources affect how you feel.
For example, some folks do just fine with dairy, whereas others don’t.
You might also tinker with how much protein you’re eating.
If you want extra help managing hunger while leaning out, you might dial your protein up.
On the other hand, if you want more carbs or fats for training or to gain weight, you might dial your protein down.
Of course, you’ll want to adjust your fat and carb intake as you do this as well.
You might not get this all figured out right off the bat.
It might be an ongoing process.
You’ll never be perfect.
You can be consistent.
You’ve got this.