How Much Protein Do Cyclists Need? The Research in Grams per Kilo

James. You're listening to the WattPlan Podcast, and I'm James. I build WattPlan around a family and a job, chase the odd podium, and read more sports science than is good for me. Today it's protein, which every rider I know either ignores completely or buys in a two kilo tub. How much do cyclists actually need, does it matter when you eat it, and does any of it make you faster? Lyra, our AI research voice, has read the studies, and they're all linked in the show notes.

Lyra. Somewhere between 1.4 and 2 grams per kilo of body weight a day, and on a hard training day the newer studies put it near the top of that, around 1.6 to 1.8. For a 70 kilo rider that's 100 to 140 grams a day, spread across four meals of 20 to 40 grams each. Nothing exotic, and no tub required.

James. Where does the range come from? Because I've heard everything from "you barely need any" to "two grams per kilo or you're wasting your training".

Lyra. The range is the International Society of Sports Nutrition's position stand, from Jäger and colleagues in 2017. It puts exercising people at 1.4 to 2 grams per kilo a day, and it's blunt about priorities. For endurance riders carbohydrate comes first, because that's what performance runs on. Protein's job is to limit muscle damage and help you recover. [1]

James. So why not just sit at the bottom, 1.4, and spend the calories on pasta?

Lyra. Because the tracer studies say a hard day needs more. Kato and colleagues used a method that measures how much protein the body actually uses, in six endurance-trained men after a 20 kilometre run. The requirement came out at about 1.65 grams per kilo, with a recommended intake of 1.83. That's double the figure for the general population and above the old 1.2 to 1.4 that endurance riders were given for years. [2]

James. Hang on, six men. That's a dinner party, not a study.

Lyra. It is small, and it's runners rather than cyclists. But a second trial points the same way. Williamson and colleagues fed ten endurance-trained runners either 0.94, 1.2 or 1.83 grams per kilo through four days of hard training. Only the highest intake kept them in positive protein balance, meaning they were building more than they were breaking down. And their five kilometre time trial tended to hold up better on it, though with ten people that didn't reach significance.

James. Right, so what about after a ride? Is the thirty-minute window a real thing or a marketing thing?

Lyra. The thirty grams is real. The thirty minutes is mostly marketing. Churchward-Venne and colleagues gave 48 endurance-trained men 45 grams of carbohydrate with either nothing, 15, 30 or 45 grams of milk protein after a session. Thirty grams raised the rebuilding of muscle fibres by about 46 percent compared with carbohydrate alone, and 45 grams added nothing more to that. [4]

James. So 30 is the number and 45 is just expensive wee.

Lyra. For the muscle fibres, yes. Whole-body protein balance did keep rising with the bigger dose, so it isn't entirely wasted, but the repair most riders care about was maxed at thirty. And on timing, the position stand says the anabolic effect of a session lasts at least 24 hours. So the meal after your ride is one of four or five that count that day. A rider who eats 30 grams at breakfast, lunch and dinner and a bit before bed is covered without timing anything.

James. Does any of this make me faster, though? Or is this all tidying up after the ride?

Lyra. Mostly tidying up, and the evidence is honest about that. A network meta-analysis published in March this year pooled 35 trials and 1,211 trained participants, comparing protein, creatine and omega-3. For endurance performance protein came out best of the three, but the effect was small. It's a reason to get your intake right, not a reason to expect watts from a shaker. Creatine won on strength and omega-3 on recovery, if you're wondering.

James. Okay. Now the bit I'm actually interested in. I'm not 27 any more. Do older riders need more?

Lyra. Probably at the top of the range, and here's the lead. Doering and colleagues followed five masters triathletes, average age 53, and six younger ones through three days of hard training. The older group's muscle rebuilt more slowly, about 1.5 percent a day against 1.7, and their time trial ten hours after a muscle-damaging run was about 3 percent slower than baseline, against 1.4 percent for the younger riders. It's five people, so it's a lead rather than proof, but it fits the position stand's note that the best dose per meal depends on age.

James. So if you're over fifty, eat more per meal, not just more in total.

Lyra. That's how I'd read it. Thirty to forty grams a meal rather than twenty, and the upper half of the daily range. And the pre-bed serving matters more for you, because that's a long stretch with nothing coming in. Thirty to forty grams of casein before bed raises overnight muscle protein synthesis. A bowl of Greek yoghurt does it. You don't need a product.

James. Let's make this practical for everyone. If you're new to this and you've never thought about protein?

Lyra. If you're new to this, do one thing. Put a protein source in your breakfast, because that's the meal most riders skip it in. Eggs, yoghurt, milk on your porridge. Then make sure dinner has a proper portion. That alone gets most people from a low intake into the range, without weighing anything.

James. And if you train with power and you're doing the hard sessions?

Lyra. If you train with power, work out your number. Your weight in kilos times 1.6 to 2 on a hard week, times 1.4 on an easy one. Then split it four ways. After the hard sessions, thirty grams with your carbohydrate within a couple of hours. And remember what WattPlan tells you on the bike is about carbohydrate, feeds on a timer through the ride, because that's what the ride runs on. Protein is a day's job, so it leaves that to your meals.

James. And if you race?

Lyra. If you race, your hard days are harder and closer together, so you live at the top of the range through a build and through race weeks, and you add the pre-bed serving. And you treat protein as recovery, never as fuel. The riders who under-eat carbohydrate and over-buy protein have it backwards. Fix the carbs first.

James. Surely there's a point where more protein just stops doing anything, though?

Lyra. There is, and the studies find it. Forty-five grams in one sitting did no more for muscle repair than thirty. And the position stand's range tops out at 2 grams per kilo for a reason. Above that there's no evidence of more recovery or more fitness for an endurance rider, just fewer calories left for the carbohydrate you actually need.

James. What can't the research tell us?

Lyra. Plenty. The studies that set the 1.6 to 1.8 figure are six and ten men, both runners. There's no equivalent in women, and none in riders over 50, so the masters advice rests on five triathletes and a caveat. The post-ride dose study measured protein synthesis over six hours, not fitness over a season. Nobody has run a season-long trial of protein intake on cycling performance. The daily range is built from metabolism, not from race results.

James. So this week. Breakfast gets protein, hard sessions get thirty grams after, and if you're my age a yoghurt before bed. And stop pretending the tub is the training.

Lyra. And on a rest day, when the app nudges you about protein and fluids, that's the day the protein is the training. Recovery is fuelled, not waited for.

Lyra. The full article and every study we mentioned are on the WattPlan blog, linked in the show notes. And if you've enjoyed this, follow the WattPlan Podcast wherever you're listening, so you don't miss the next one.

James. And if you want a plan built around the time you've actually got, get WattPlan on the App Store or Google Play. Thanks for listening.

Voices produced with ElevenLabs. James's voice is a clone of his own, Lyra is an AI voice, and James reviews every episode.