How Much Protein Do Triathletes Actually Need? A Science-Based Guide

Protein gets less airtime than carbohydrate in triathlon nutrition — most of the conversation is about race-day fuelling — but it’s just as relevant to how well you recover between sessions and adapt to training. Here’s what the evidence actually supports, without the marketing noise around “high protein” everything.

The Target Range

Sports nutrition guidance for endurance athletes generally sits between 1.2 and 1.6g of protein per kilogram of bodyweight per day — higher than the general population’s guideline intake, but well below the very high targets sometimes recommended for pure strength athletes. A 65kg triathlete training seriously is looking at roughly 78-104g of protein a day; a 75kg athlete around 90-120g. Athletes in a heavy strength-training block or coming back from injury may sit toward the top of that range or slightly above it.

Why Endurance Athletes Need More Than Non-Athletes

Long endurance sessions don’t just burn carbohydrate and fat — some protein is used for fuel too, particularly late in long sessions when glycogen is depleted. On top of that, the muscle repair demands of high weekly training volume across three disciplines are real, even without a strength-focused programme. That combination is why endurance athletes need meaningfully more protein than a sedentary adult, even though the target is lower than a bodybuilder’s.

Timing: Does It Matter?

Total daily intake matters more than precise timing, but there’s still a reasonable case for spreading protein across 3-4 meals rather than loading it all into one, since muscle protein synthesis responds better to repeated moderate doses (roughly 20-40g per sitting) than one very large one. A protein-containing meal or snack within a couple of hours of a hard session is a sensible habit, not because the “window” is as narrow as older advice suggested, but because it’s an easy way to hit your daily total consistently.

Where Most Age-Groupers Actually Fall Short

Breakfast: a bowl of cereal or plain porridge is carbohydrate-heavy and protein-light — adding Greek yoghurt, eggs or a scoop of protein powder closes the gap fast.
Post-long-ride recovery: it’s easy to reach for carbohydrate-only recovery drinks after a big ride and forget protein entirely.
Plant-based athletes: hitting the target is entirely achievable on a vegan or vegetarian diet, but it takes more deliberate meal planning around combinations like lentils, tofu, and plant proteins to hit the same daily total.

The Bottom Line

Aim for 1.2-1.6g/kg bodyweight daily, spread across meals, with real food doing most of the work and supplements filling genuine gaps rather than replacing meals outright. It’s a less glamorous number than a race-day nutrition plan, but it’s one of the more reliable levers you have for recovering well between the sessions that actually make you faster.