Protein After 40: Why Masters Athletes Need More Than You Think

Okay, confession time: I used to recommend 1.6 grams of protein per kilogram of body weight to all my athletes—whether they were 25 or 55. I figured, "Hey, protein is protein, right? The body knows what to do with it."

Then I started working with more masters CrossFit competitors and endurance athletes in their 40s, 50s, and 60s. And something wasn't adding up. They were hitting their protein targets, training hard, sleeping well... but their muscle mass wasn't responding like my younger clients'. Some were even losing lean tissue despite increasing their training volume.

So I dug into the research—and honestly, it was a wake-up call. The data on what's called "anabolic resistance" in aging muscle is pretty compelling. A 2020 systematic review in Sports Medicine (doi: 10.1007/s40279-020-01307-7) analyzed 36 studies and found that older adults need about 0.4–0.6 g/kg more protein per meal to stimulate muscle protein synthesis compared to younger adults. That's not a small difference—we're talking about needing nearly double the per-meal dose to get the same anabolic signal.

Here's what that looks like in practice: if you're a 180-pound (82 kg) masters athlete, instead of spreading 130 grams of protein evenly across 4 meals (about 32g each), you might need 40–50 grams per meal to overcome that resistance. And timing matters way more than I used to think.

Quick Facts Box

What the Research Actually Shows

Let me geek out for a minute—this is where it gets interesting. The mechanism behind anabolic resistance isn't just about digestion or absorption (though those can decline slightly). It's about how your muscle cells respond to the amino acid signal.

A 2022 randomized controlled trial (PMID: 35427456) followed 87 healthy adults aged 65–85 for 12 weeks. They compared three protein doses post-resistance training: 20g, 35g, and 50g. The 20g group showed minimal muscle protein synthesis response—basically, their muscles didn't "hear" the signal. The 35g group had a moderate response. But the 50g group? That's where they saw robust muscle protein synthesis rates comparable to what you'd expect in younger adults.

Now, here's something that changed my clinical approach: the bedtime protein study. Published in Medicine & Science in Sports & Exercise (2021;53(8):1587-1595), researchers had older men (average age 71) consume either 40g of casein protein or a placebo before sleep. Over 12 weeks, the protein group gained 2.3 kg of lean mass with resistance training, while the placebo group gained only 1.2 kg. That's nearly double the muscle growth from a single timed dose.

And it's not just about quantity—quality matters too. Leucine is the key trigger for muscle protein synthesis, and older muscles need more of it to "flip the switch." A 2023 meta-analysis in the American Journal of Clinical Nutrition (doi: 10.1016/j.ajcnut.2023.04.025) pooled data from 18 RCTs (n=1,247 total participants) and found that meals containing at least 2.5–3.0g of leucine produced significantly better muscle protein synthesis responses in older adults compared to lower-leucine meals with the same total protein.

For reference: whey protein has about 10–11% leucine by weight, so 40g of whey gives you 4–4.4g of leucine—well above that threshold. Plant proteins typically have 6–8% leucine, so you'd need 50–60g to hit the same leucine dose.

Dosing & Recommendations That Actually Work

Alright, let's get practical. Here's exactly what I tell my masters athlete clients—and yes, I've tested this protocol on myself during my competitive triathlon years as I moved into my 40s.

Daily Total: 1.8–2.2 g/kg body weight (0.82–1.0 g/lb). If you're actively trying to build muscle or recovering from injury, lean toward the higher end. A 2024 position stand from the International Society of Sports Nutrition (doi: 10.1186/s12970-024-00600-0) specifically notes that athletes over 40 may benefit from the upper range of these recommendations.

Per-Meal Minimum: 35–50 grams. This is non-negotiable if you want to overcome anabolic resistance. Spread across 4 meals, that's 140–200g total—which fits perfectly with the daily target for most athletes.

Timing Matters More Than Ever:

• Post-workout: 40–50g within 2 hours. I prefer whey isolate here for fast absorption.
• Bedtime: 30–40g of slow-digesting protein (casein or a casein/whey blend). This provides amino acids throughout the night when muscle repair is most active.
• First Meal: Don't skip breakfast protein. Overnight fasting plus age-related resistance means your muscles are primed for amino acids in the morning.

Protein Quality: Look for products that disclose their leucine content or at least their amino acid profile. Thorne's Whey Protein Isolate lists 2.7g leucine per 25g serving—that's excellent. If you're plant-based, pea/rice blends (like NOW Sports Pea Protein) can give you a complete amino acid profile.

What About Whole Foods? Absolutely—I'm not saying live on shakes. But here's the thing: 35–50g from whole foods is a lot. That's 5–6 ounces of chicken breast plus a cup of Greek yogurt. Or 7 eggs. Many masters athletes struggle to eat that much in one sitting, especially with busy schedules. That's where strategic supplementation comes in.

One of my clients—a 52-year-old cyclist—was eating "healthy" but only getting about 20g protein per meal. We bumped him to 40g per meal with a post-ride shake and bedtime casein. In 3 months, his DEXA scan showed a 4-pound lean mass increase despite reducing his training volume by 10%. He said, "I haven't felt this strong since my 30s."

Who Should Be Cautious

Look, protein is generally safe, but there are a few exceptions:

Kidney Issues: If you have pre-existing kidney disease (not just "my creatinine is slightly high"), check with your nephrologist before increasing protein. For healthy kidneys, high protein intake isn't harmful—a 2023 review in Journal of Renal Nutrition (PMID: 36708923) confirmed this in athletes without kidney disease.

Gout: High-purine proteins (organ meats, some seafood) might trigger flares. Whey and plant proteins are typically lower in purines.

Digestive Issues: Some older adults produce less stomach acid, which can affect protein digestion. If you experience bloating or discomfort, try digestive enzymes with meals or consider hydrolyzed proteins (pre-digested).

Medication Interactions: Levodopa for Parkinson's can compete with amino acids for absorption—time protein doses away from medication if this applies.

FAQs

Q: Can I just eat more protein throughout the day instead of bigger meals?
A: Not really. The research shows it's the per-meal dose that triggers muscle protein synthesis. Six small 20g meals won't give you the same anabolic signal as four 40g meals. Your muscles need that threshold dose.

Q: What if I'm trying to lose weight and build muscle?
A: Keep protein at 2.0–2.2 g/kg and adjust carbs/fats for your calorie deficit. Higher protein preserves lean mass during weight loss—a 2024 study in Obesity (PMID: 38224568) found older adults lost 40% less muscle on high-protein diets during calorie restriction.

Q: Are plant proteins as effective for older athletes?
A: Yes, but you need more. Plant proteins are typically lower in leucine and less digestible. Aim for 50–60g per meal from a complementary blend (like pea + rice) or add 3–5g of pure leucine to hit that 2.5–3.0g leucine threshold.

Q: When should I take BCAAs instead of whole protein?
A: Honestly? Almost never. Whole protein gives you all essential amino acids plus other nutrients. Save your money—invest in quality protein powder instead.

Bottom Line

Here's what I want you to remember:

• Masters athletes need more protein than younger athletes—1.8–2.2 g/kg daily isn't excessive, it's necessary.
• Per-meal doses of 35–50g overcome anabolic resistance. Smaller, frequent meals don't work as well.
• Timing matters: post-workout and bedtime protein are non-negotiable for optimal muscle maintenance.
• Quality counts—look for third-party tested proteins with transparent amino acid profiles.

The good news? This works. I've seen 60-year-old runners regain muscle they thought was gone forever, and 50-year-old CrossFit athletes set new PRs. Your muscles might need a louder signal, but they're still listening.

Disclaimer: This is general information, not medical advice. Consult with a healthcare provider before making significant dietary changes, especially if you have health conditions.