From muscle growth to longevity, a clear look at how much, when, and why it matters.
Story By Dr. Edwin Spencer
Appeared in Cityview Magazine, Vol. 42, Issue 3 (May/June 2026)
When you get a call from one of your mentors, you usually take it. This call was interesting as it was an introduction to another surgeon on the west coast who was equally interested in the health wellness space. He had noticed some of the same trends in outcomes and was interested in improving them. So, I walked out to the dock and we exchanged stories and ideas.
I’ll be honest — conversations like that are where I do some of my best thinking. Whether I’m knee-deep in the headwaters of the Soque River working a dry fly upstream into a quiet run, or in the deer stand witnessing the woods come alive in the morning, my mind is always turning over problems. My wife will tell you I’m not always the best at shutting it off. Work/life balance is probably the thing I struggle with most. But every once in a while, the lack of balance pays off.
Protein is everywhere these days — added to shakes, bars, snacks, and even coffee. It’s trending across social media, but that often leaves people wondering: What’s actually true? Are some proteins better than others? Does timing matter? And is protein important only for people who train, or for everyone? These are questions I hear often, so let’s break the topic down into something digestible — pun intended.
What Is Protein?
Protein is one of the three major macronutrients, along with fats and carbohydrates. It’s made up of amino acids, which can come from either animal or plant sources. The human body uses about 20 amino acids to build all its proteins, but 9 of these are essential — meaning your body cannot make them. They must come from food.
How Does the Body Use Protein?
Proteins are the building blocks of enzymes, tissues, and many structural components of the body. Several amino acids are key for producing hormones and neurotransmitters — for example, tyrosine is used to make dopamine, norepinephrine, and thyroid hormone, while tryptophan helps produce serotonin and melatonin.
The body generally avoids using protein as a primary fuel source because it takes significantly more energy to metabolize compared to fats or carbohydrates — roughly 2–3 times more. This is one reason people on a carnivore diet often report meaningful weight loss. I like to think of it the way I think about a well-planned surgery: you use the right tool for the right job. A fire is a useful analogy for protein’s metabolic role: carbohydrates are quick-burning paper, fats are slow-burning logs, and protein is the iron grate holding the whole thing together. You can burn the grate for fuel, but it’s inefficient — the body prefers to use protein for structure and function rather than energy.
What Is the Best Source of Protein?
This is one of the most common questions I hear, especially in the gym. I’ll admit my personal bias toward a thick, juicy, rare ribeye. It’s a running joke in my house — my family knows that a good steakhouse makes me genuinely happy. But research shows that vegans can still achieve muscle protein synthesis (MPS) rates comparable to omnivores, provided they are very intentional about getting all essential amino acids, especially leucine, a key driver of MPS.
Common plant proteins that meet WHO essential amino acid recommendations include soy, quinoa, brown rice, and pea protein. However, they still don’t match the amino acid profiles of beef, chicken, eggs, or whey. A useful metric here is the Protein Digestibility Corrected Amino Acid Score (PDCAAS), which accounts for both amino acid content and digestibility. A perfect score of 1.0 means the protein is complete and highly digestible.
Among plant-based options, soy scores 0.91, quinoa 0.87, chia 0.73, and pea protein 0.68. Animal-based proteins — eggs, whey, casein, and fish — score a perfect 1.0, with beef and chicken ranging from 0.92 to 1.0.
A recent study comparing vegan diets (with protein supplementation) to omnivorous diets showed no significant difference in MPS regardless of protein distribution throughout the day. However, another study comparing a soy-based meat alternative with beef found significantly higher muscle fractional protein synthesis after consuming beef, corresponding to higher serum amino acid levels.
The bottom line: you can achieve adequate protein on a vegan diet, but you must be far more deliberate with supplementation and food combinations. For those interested in muscle gain, animal-based proteins make it easier to hit ideal amino acid targets. For what it’s worth, I don’t push any single approach on my patients or my own family — I just want people eating intentionally, whatever that looks like for them.
Why Does Muscle Protein Synthesis (MPS) Matter?
People often raise protein intake only in the context of training, but MPS matters for everyone. Strength and VO₂max — a measure of cardiopulmonary fitness — are two of the strongest predictors of longevity and healthspan. I think about this not just as a physician but as a husband and father. I want to be on the river, active and sharp, for as many decades as possible. That means protecting muscle mass now.
After resistance training, MPS remains elevated for about 24 hours. Consuming adequate protein during this window supports recovery and growth. Higher protein intake also benefits endurance athletes, with research showing improvements in VO₂max (Cardiopulmonary fitness), peak workload, lean mass, and time trial performance.
“Eat whole foods with plenty of protein, move your body, get sunlight, and sleep well.”
How Much Protein Do You Need?
Strength gains increase in a dose-dependent manner with protein intake. For every 0.1 g/kg increase, strength improves by about 0.72%, up to roughly 1.5 g/kg — approximately 0.75 grams per pound of body weight. I personally aim for 1 gram per pound of ideal body weight to ensure adequacy.
That said, protein alone isn’t enough. Without resistance training, simply increasing intake won’t significantly improve strength. You must move your body, there is no shortcut.
When Should You Consume Protein?
For years, the prevailing belief was that protein must be consumed immediately after training, and that the body can only process 30 grams per meal. Newer research challenges both ideas. A study comparing a 25-gram dose of protein to a 100-gram dose over 12 hours showed that the larger bolus produced greater and longer-lasting MPS. This means you can safely consume more than 30 grams per meal, and larger servings can help maintain an anabolic — muscle-building — state.
The “anabolic window” debate continues, but total daily protein intake is probably more important than precise timing. Personally, I aim for 40–50 grams within an hour after training, using a high-quality whey isolate for maxim leucine delivery. On mornings after a hard workout, my family knows the blender is coming out for the smoothie and eggs and avocado are on the table.
Are There Downsides to Protein?
The only consistently noted risk relates to red meat — and specifically processed red meats like ham and bacon, which are associated with approximately a 20% increase in gastrointestinal cancers, particularly colorectal cancer. I found this particularly disappointing as bacon makes almost anything taste better. These findings often fail to account for confounding lifestyle factors like exercise and overall diet quality. In contrast, fruit and vegetable intake — particularly those high in soluble fiber — is protective, likely due to beneficial effects on the gut microbiome along with phytonutrients and antioxidants.
What Are the Other Effects of Protein?
It’s hard to watch television anymore without an advertisement for a glucagon-like peptide (GLP) medication for weight loss. What most people don’t realize is that amino acids — particularly glutamine, arginine, and leucine — are potent natural stimulators of GLP from the gut, which promotes satiety. Protein also has a stabilizing effect on blood sugar levels. A well-constructed, protein-rich diet does quietly in the background what some of these medications aim to do artificially.
The Takeaway
Protein intake and exercise are essential for stimulating muscle protein synthesis, improving strength, and enhancing endurance — all of which are key predictors of longevity. Choose proteins with high PDCAAS scores and sufficient leucine to maximize benefit. While I enjoy a good ribeye, I diversify with eggs, poultry, pork, and fish, and I make sure to get at least 30 grams of soluble fiber from fruits and vegetables daily. That is, essentially, an omnivore diet, and I believe it covers all the bases — for me and for my family.
Back to the Conversation
At the end of the conversation, we both agreed that nutrition was the key lever to affect outcomes while supplementing for deficiencies and additional needs. But could we accelerate the recovery and improvement even more? I had taken some peptides after a surgery years ago and recovered very well as had many of my patients. However, there is a paucity of human literature regarding their use. After a few more conversations we developed OPEN, Orthopaedic Peptide Evaluation Network with a scoring system that we can implement to track outcomes. We will launch this soon and begin collecting data…stay tuned. Having said that, I believe that peptides will only have a meaningful positive effect if the baseline nutrition is optimized.
In many ways, all the current nutrition data just reinforces what generations before us already practiced: eat whole foods with plenty of protein, move your body, get sunlight, and sleep well. As Solomon wrote in Ecclesiastes, “There is nothing new under the sun.”
That truth steadies me — when taking care of patients, on the river, and at the dinner table with my family. Regardless of where the science leads next, we’d all do well to deepen our faith, love our families and friends profoundly, and recognize the fundamental meaningfulness in God’s plan for each of us and for our fellow man.
Dr. Edwin Spencer is an orthopedic surgeon and a longtime contributor to Cityview. ◆
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