The Definitive Guide to Protein

Protein is an incredible essential macronutrient. Fat is plentiful, even when you’re lean, and there are only two absolutely essential fatty acids; the rest we can manufacture from other precursors if required. Carbs we can produce from protein, if we really must, or we can just switch over to ketones and fats for the bulk of the energy that would otherwise come from carbs. Protein cannot be made with the raw material available in our bodies. We have to eat foods containing the range of amino acids that we need.

In other words, protein is incredibly important—which is why today I’m writing a definitive guide on the subject. After today’s post, you’ll have a good handle on the role protein plays in the body, how much protein you need to be eating, which foods are highest in protein, and much more.

First, what roles does protein play in our bodies?

It helps us build muscle.

We use it to construct new cells, muscles, organs, and other tissues.

It’s a chemical messenger, allowing us to turn on and turn off genes.

It forms the fundamental substrates used to manufacture enzymes, DNA, and hormones.

It can even be a fuel source, either directly or through conversion into glucose.

Now, am I saying that the steak you eat directly becomes a thyroid hormone? Does chicken breast turn into DNA?

No. But the strings of amino acids and peptides that make up proteins are eventually broken down and cobbled back together to fulfill all the roles I describe. Every bite of protein you consume contributes toward maintenance of your physiology. And we can’t make new protein. We have to eat it.

What’s the Recommended Daily Protein Intake?

If you go by the official numbers, the Recommended Daily Allowance (RDI) for protein is 0.8 grams of protein per kilogram of bodyweight, or 0.36 g protein/lb. That’s what the “experts” say to eat. That’s all you “need.” I disagree, and I’ll tell you why down below, but there’s the official answer.

Sufficient is one thing. Optimal is another. In reality, the amount of protein required for optimal health and performance is different for every population.

Protein Intake for Athletes and Exercisers

Athletes need more protein than the average person, but perhaps not as much as most fitness enthusiasts think (or consume). A 2011 paper on optimal protein intakes for athletes concluded that 1.8 g protein/kg bodyweight (or 0.8 g protein/lb bodyweight) maximizes muscle protein synthesis (while higher amounts are good for dieting athletes interested in preserving lean mass), whereas another settled on “a diet with 12-15% of its energy as protein,” assuming “total energy intake is sufficient to cover the high expenditures caused by daily training” (which could be quite high).https://www.ncbi.nlm.nih.gov/pubmed/1763249‘>² One study even found benefit in 2-3 g protein/kg bodyweight (0.9-1.4 g protein/lb bodyweight) for athletes, a significant increase over standard recommendations.https://www.ncbi.nlm.nih.gov/pubmed/17299116‘>⁴ Another study in women showed that a 1.6 g protein/kg bodyweight (or 0.7 g protein/lb bodyweight) diet led to more weight loss, more fat loss, and less lean mass loss than a 0.8 g protein/kg bodyweight diet.https://www.ncbi.nlm.nih.gov/pubmed/23097268‘>⁶

Protein Intake When Injured

Healing wounds increases protein requirements. After all, you’re literally rebuilding lost or damaged tissue, the very definition of an anabolic state, and you need protein to build new tissue. One review recommends around 1.5 g protein/kg bodyweight or close to 0.7 g protein/lb bodyweight for injured patients.https://www.ncbi.nlm.nih.gov/pubmed/16886097‘>⁸ That said, active seniors will do better with even more and evidence suggests that increasing protein can both improve physical performance without necessarily increasing muscle mass and increase muscle mass when paired with extended resistance training in the elderly.https://www.ncbi.nlm.nih.gov/pubmed/22889730‘>¹⁰https://www.ncbi.nlm.nih.gov/pubmed/18175736‘>¹²

High Protein Benefits

Beyond supporting the basic underpinnings of human physiology, eating more protein than the RDI offers extra benefits.

Protein Satiety

As a fundamental biological motivator, hunger can’t be ignored forever. Eventually you crack, and the diet fails. Eventually, you’re going to eat. Where extra protein helps is adding satiety. Successful fat loss comes down to managing your hunger; protein helps you manage it without relying on sheer willpower.

Protein For Muscle Gain and Muscle Retention

To increase muscle protein synthesis, you need two primary inputs: resistance training and protein intake. You can lift all the weights in the world, but if you’re not eating enough protein, you won’t gain any muscle. You can’t make extra, it has to come from outside sources.

And then during active weight loss, upping your protein intake will minimize the loss of muscle that usually accompanies fat loss. In women, for example, cutting calories while keeping protein higher than normal led to better lean mass retention than cutting the same number of calories and keeping protein low.https://www.ncbi.nlm.nih.gov/pubmed/24015701‘>¹⁴