Protein and endurance: what the research really shows
Protein in your training drink isn’t just a gym thing. A University of Texas study showed that a mix of carbohydrates and protein extended endurance significantly more than carbohydrates alone — and that result changed the way many endurance athletes approach training nutrition.
Why protein matters during training
For a long time, the standard for endurance athletes was simple: take carbohydrates before and during training. Glycogen is the fuel, carbohydrates replenish it — logical, and it works. But is that always enough?
It turns out that it isn’t always. Amino acids, the building blocks of protein, also play a role in the body’s aerobic energy production. When training drags on and becomes intense, the body starts using amino acids as an additional source of energy. If they aren’t available in sufficient amounts from food, this extra support is missing entirely.
John L. Ivy, who led the research at the University of Texas at Austin, put it this way: amino acids may provide additional energy that supports aerobic energy production. Put more simply, protein is not only a building material for muscles — it is also fuel when the training load is prolonged.
The study: protein extends endurance
Trained cyclists took part in the study. They exercised to exhaustion on three separate occasions, receiving a different drink each time:
- placebo drink — average time to exhaustion 12.7 minutes
- carbohydrate solution — 19.7 minutes
- carbohydrate and protein mix — 26.9 minutes
That is a significant difference. Carbohydrates alone extended the time by about 7 minutes compared with the placebo. But the combination of carbohydrates and protein added another 7 minutes — that is, 14 minutes more endurance in total compared with the placebo.
In ratio terms: those who drank the drink with protein could train for 26.9 minutes, where the placebo group managed only 12.7 minutes. That is almost twice as long a training session — same cyclists, same day, only the drink differed.
How to use protein in a training drink
The study used a drink called Accelerade, which has a carbohydrate-to-protein ratio of 4:1. That means one gram of protein for every four grams of carbohydrate. The makers of Accelerade took part in funding the study, which is worth bearing in mind — but the results are nonetheless groundbreaking.
For short, moderate-intensity training sessions (under an hour), a plain carbohydrate drink works well. But when training stretches beyond an hour and the intensity is high — a long bike ride, a longer run, interval training — adding protein to the mix is worth serious consideration.
A practical approach: mix an isotonic sports drink or maltodextrin with whey protein in a 4:1 ratio. It’s cheaper than most ready-made sports drinks and lets you apply the same principle. The key is not to overdo the amount of protein — too large a dose during training can upset digestion. A moderate addition, a 4:1 ratio, works best according to the research.
Honestly, this isn’t a new revolution, just a more precise understanding of what the body needs when the training load is prolonged. If endurance training is part of your life, it’s worth putting that knowledge to use.
FAQ
Is a protein supplement as important for an endurance athlete as for a gym-goer?
For different reasons, but yes. In the gym, you use protein mainly to build muscle. In endurance training, it plays the role of extra energy and holds back muscle breakdown when the training load is prolonged.
When should you drink protein during training?
The same principle as with carbohydrates — in small portions throughout the whole training session, especially in sessions lasting over an hour. Taking a large dose in one go while fasted isn’t sensible.
Can you mix ordinary whey protein with a sports drink?
Yes, it’s one of the cheapest and simplest solutions. Whey protein dissolves well and is absorbed quickly — it’s suitable for use during training. Just check that the mix doesn’t get too sweet — the taste can surprise you.
Source: WHO – physical activity.
Come and train! ArtGym
