Protein and Muscle as We Age: How Much You Actually Need

For most of my life I thought of protein as a young man's concern.

I started training at twelve. Through my twenties and thirties, protein was about building something — putting on size, recovering from hard sessions, chasing a number in the gym. I naturally thought that as I got older and trained less aggressively, I'd need less of it.

That turns out to be backwards. And it's one of the more consequential things I got wrong.

The Number Most of Us Are Using Is a Floor, Not a Target

If you've ever looked up how much protein you need, you probably found the RDA: 0.8 grams per kilogram of body weight. For someone at 170 pounds, that's about 62 grams a day.

Here's what that number actually means. The RDA was established as the minimum required to prevent deficiency in most healthy adults. It answers the question "how little can I get away with?" — not "how much do I need to thrive?"

Those are different questions, and the gap between them widens as our bodies change.

What Actually Changes

Two things shift, and they compound.

Muscle becomes something you maintain

Starting somewhere in the fourth decade, adults lose muscle mass gradually and continuously. The decline is slow enough that many people don't notice it happening — they notice the result. The suitcase feels heavier. Getting up off the floor takes a hand on the coffee table. Recovery from a long day takes longer than it used to.

This progressive loss of muscle mass and strength has a name — sarcopenia — and it isn't a disease you catch. It's the default trajectory in the absence of enough stimulus and enough protein.

Your muscles respond less efficiently to the same protein

This is the part I'd never heard of, and it changes what you do about the first one.

When you eat protein, your body uses it to build and repair muscle tissue. As we age, that response becomes blunted — the same amount of protein produces less of a building signal than it did twenty years earlier. Researchers call this anabolic resistance.

The practical consequence is uncomfortable: at exactly the point where you're losing muscle, your body gets worse at using the raw material to replace it.

The counterintuitive part

Many of us quietly eat less protein as we get older. Appetite softens, meals get smaller, meat feels heavier than it used to.

Meanwhile the requirement is going up.

So How Much Do You Actually Need?

Expert groups that have looked specifically at protein needs in later life — among them the PROT-AGE study group — recommend intakes meaningfully above the RDA. Generally in the range of 1.0 to 1.2 grams per kilogram of body weight per day for healthy adults, and higher for those training hard or recovering from illness.

Those recommendations were written with older adults in mind. But the shift they are responding to does not switch on at sixty-five. It is gradual, and it begins decades earlier — which makes this less a line to cross than a direction to start moving in.

Translated into pounds, that's roughly 0.45 to 0.55 grams per pound.

The gap between those two columns is the thing worth noticing. For a lot of people it's twenty to thirty grams a day — not a wholesale diet change, but not nothing either.

One note before we go further: if you have kidney disease or any condition where protein intake is medically managed, these general figures don't apply to you. That's a conversation for your doctor, not a blog post.

The Part Almost Nobody Gets Right

Here's where the advice usually stops — hit your daily number. But total intake is only half the story.

Your body doesn't bank protein. It can't take a large evening intake and apply it retroactively to a morning that had none. Muscle protein synthesis is triggered meal by meal, and each meal needs to clear a threshold to trigger it at all.

Which means how you distribute protein across the day matters as much as the total.

Many of us eat backwards. Toast or coffee for breakfast. Something light at lunch. Then most of the day's protein arrives at dinner, when the body can only use so much at once.

A more useful pattern is roughly even distribution — a meaningful amount of protein at each of three or four points in the day, rather than one large delivery at the end of it.

Because of anabolic resistance, the per-meal threshold also rises as we age. A serving that would have triggered a full response at thirty may not at sixty. That's an argument for a bit more at each meal, not just more overall.

Quality: Not All Protein Signals Equally

Protein is made of amino acids. Nine of them are essential — your body can't make them, so they have to come from food.

One in particular, leucine, acts as something close to a switch. It's the amino acid most directly associated with triggering muscle protein synthesis. A protein source rich in leucine sends a stronger signal than one that isn't.

This is where plant protein gets unfairly dismissed, and where the picture is more interesting than the usual argument allows.

Pea protein contains all nine essential amino acids — it's a complete protein, which many plant sources aren't. And in a twelve-week randomized controlled trial comparing pea protein to whey during resistance training, muscle thickness gains were statistically equivalent between the two groups. The researchers concluded that pea protein could serve as an alternative to whey-based products.

That doesn't make them identical. Whey is somewhat higher in leucine per gram and digests faster. But the outcome data over a real training period is closer than many people assume, and the gap narrows further at adequate doses.

We'll take that comparison apart properly later in the series. For now, the useful conclusion is simpler than the debate: complete plant protein works.

Where This Gets Practical

Twenty to thirty extra grams a day sounds like a lot until you break it down. It's one additional protein-forward moment in your day, most days.

Some ways that looks in practice:

• Add protein to breakfast if it's currently coffee and something beige. For many of us this is the highest-leverage change available.
• Make the mid-morning or mid-afternoon gap a protein moment rather than a carbohydrate one. Same calories, different signal.
• Anchor each meal around a protein source before deciding what goes with it.
• Around training, protein before or after the session supports recovery. The total across the day still matters more than hitting a precise window.

What We Made, and Why 12 Grams

Every LAST Bar has twelve grams of complete plant protein, led by pea protein — all nine essential amino acids, plus iron and arginine.

Twelve isn't an accident, and it isn't a maximum. It's the amount that fits into a bar that still tastes like food rather than a supplement, alongside eight to nine grams of prebiotic fiber and zero added sugar. We could have pushed the protein number higher. The bar would have been drier, chalkier, and harder to want.

The point isn't that one bar meets your daily requirement. It doesn't. The point is that it closes the gaps — mid-morning, mid-afternoon, before or after a workout, the drive home, the airport — that many of us fill with something offering no protein at all.

That's the whole design philosophy: not a meal replacement, but a better version of a moment you're already having.

Whichever gap you're trying to close, a box of twelve is the practical way to do it — one decision, ready whenever the moment shows up.

The Short Version

• The RDA is a floor to prevent deficiency, not a target for aging well.
• Muscle declines gradually from midlife, and your body gets less efficient at using protein at the same time.
• Recommended intake for healthy adults as we age runs meaningfully above the RDA — roughly 0.45 to 0.55 grams per pound.
• Distribution matters. Three or four protein moments beat one large dinner.
• Breakfast is where many of us have the most room to improve.
• Complete plant protein works. Pea protein contains all nine essential amino acids.

Next in the series: the nutrient almost everyone under-eats — fiber, your gut, and why the source matters more than the number.

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Sources

• Bauer et al., PROT-AGE Study Group — Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People, Journal of the American Medical Directors Association
• Babault et al. — Pea proteins oral supplementation promotes muscle thickness gains during resistance training, Journal of the International Society of Sports Nutrition
• National Institute on Aging — Age-related muscle loss and physical function (nia.nih.gov)
• Institute of Medicine — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids
• Wall et al. — Anabolic resistance of muscle protein synthesis with aging, Nutrition Reviews
• Banaszek et al. — The Effects of Whey vs. Pea Protein on Physical Adaptations Following 8 Weeks of High-Intensity Functional Training, Sports

This article is general information, not medical or dietary advice. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

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This post is part of the Resetting Normal Series. Read the full series: Part 1: Resetting Normal · Part 2: What's Actually in Your Protein Bar · Part 3: Protein and Muscle as We Age

Here's to aging well… Cheers!

— Joel
Founder, Five Plus Protein