New research shows endurance athletes need 1.8-2g protein per kg—essentially double the previous recommendations. Here's why it matters for endurance athletes and how to hit your targets.
A major new study just came out that's changing everything we thought we knew about protein for endurance athletes. And it turns out, Ascent checks every single box for what the science says actually works. We'll get to that later, but first: the news.
The New Science That Changes Everything
A comprehensive review just dropped in Sports Medicine titled "Protein Nutrition for Endurance Athletes: A Metabolic Focus on Promoting Recovery and Training Adaptation."
This study was recently highlighted on the SWAP (Some Work All Play) podcast, and it's the first time researchers have looked specifically at endurance athletes—not bodybuilders, not CrossFitters, but runners, cyclists, and triathletes like you.
The old recommendations said endurance athletes need 1-1.5 grams of protein per kilogram of bodyweight. Those numbers came from old nitrogen-balance equations that likely underestimated needs.
This new study uses the indicator amino acid oxidation (IAAO) method—a breakthrough approach that tracks labeled amino acids like leucine in exhaled carbon dioxide. When your body doesn't have enough protein for complete muscle synthesis, it oxidizes more amino acids. Once you hit your requirement, that oxidation plateaus.
The result? Endurance athletes need 1.8 to 2 grams per kilogram of bodyweight. For a 150-pound athlete, that's 123-136 grams per day. For a 180-pound athlete, it's 147-163 grams.
Why Endurance Athletes Need This Much
Here's the key insight: endurance sports cause massive breakdown.
Every run, every ride, you're tearing down muscle tissue. But it goes deeper than that. As the study explains, amino acids aren't just "a substrate and signal for the repair and remodeling of skeletal muscle proteins"—they're also building "new muscle mitochondrial proteins that power muscle energetics."
Your body is literally rebuilding the cellular machinery that produces energy. Without adequate protein, you trigger catabolic processes that are bad for performance and possibly unhealthy long term.
Running is a power sport. We should probably fuel like it.
The study's specific recommendations:
1.8 g/kg on standard training days
2 g/kg on recovery days with lower carb availability
0.5 g/kg immediately post-exercise (which also helps with glycogen resynthesis)
The numbers were at the high end on rest days and during carb-limited training. Master athletes over 40 likely need even more, as protein requirements increase with age.
What Does This Look Like In Real Life?
Let's make this practical. For most endurance athletes, these recommendations translate to 100-150+ grams of protein per day.
Here's the math with protein shakes:
Most protein powders deliver 20-25g per scoop. That means you would need 4-6 scoops per day to hit these targets.
Before you panic about drinking that many shakes, here's how it actually works:
One shake in the morning (25g)
One shake post-workout (20g)
Normal meals throughout the day (50-80g from chicken, eggs, yogurt, etc.)
Spacing protein intake every 3-4 hours keeps muscle protein synthesis elevated throughout the day, which is why the morning shake + post-workout shake + regular meals approach works so well. Suddenly, you're at 100-125g without stressing about it.
What Athletes Notice With Adequate Protein
When endurance athletes dial in their protein intake, the results show up fast—often within days.
Those nagging aches and pains? They fade. Recovery between hard sessions gets noticeably faster. You can string together high-quality training days without feeling wrecked.
Your body feels less "old" and "rickety." Training feels easier. You're less irritable.
When protein intake drops below these levels, everything hurts more and lasts longer. You adapt more slowly. Your body is breaking down faster than it's building back up.
It's not subtle.
The Leucine Breakthrough
Here's something most people don't know: not all protein is created equal.
Your body needs about 2-3 grams of leucine per serving to actually trigger muscle protein synthesis. That's the amino acid that tells your muscles, "hey, start rebuilding."
Most proteins don't hit that threshold. So you're drinking expensive flavored water that makes you feel full but doesn't actually flip the switch on recovery.
Ascent hits 2.6g of leucine per scoop. That's the target. Your muscles actually recover faster instead of just limping along.
Why Ascent Checks All The Boxes
Most protein powders taste like chalky sadness or are so thick you need a spoon. Athletes have tried dozens of options, and most fall short on either leucine content, taste, or mixability.
Ascent is different in two ways:
The Regular Whey - 25g protein per scoop with that critical 2.6g leucine hit. Mixes smooth. Tastes good enough that athletes actually look forward to their morning shake.
The Clear Whey - When athletes first hear about "clear whey" it sounds like marketing BS.
It's not.
Clear whey is hydrolyzed—basically pre-digested so it absorbs faster. It mixes like a hydration drink. Watery-thin, light fruit flavors, refreshing instead of heavy.
You still get 20g of protein per serving. But your stomach doesn't feel like you just chugged a milkshake.
The Daily Routine That Actually Works
Morning: One scoop Ascent Whey (25g protein) with milk, add 5g creatine and a scoop of collagen. Takes 60 seconds to make.
Post-workout: Clear Whey mixed with just water (20g protein). Light, refreshing, absorbs fast when you need it most.
Normal meals: Eggs for breakfast, chicken or fish at lunch/dinner, Greek yogurt as a snack.
That gets you to 100-125g of protein with the right leucine content to actually trigger recovery—without making protein your full-time job.
