Protein During Ultramarathons: Do You Actually Need It?

Around 5 to 10% of the energy you burn in a long endurance effort comes from protein (Tarnopolsky, 2004). The rest is carbohydrate and fat. So protein is never going to be the fuel that gets you to the finish of a 100 km trail race. That job belongs to carbohydrate.

That doesn’t make protein pointless in an ultra. It means it has a smaller, more specific job, and most of it happens in races long enough that you stop wanting sweet things.

Does protein during a race improve performance?

Not in any way the research has shown clearly. A systematic review of studies adding protein to carbohydrate during exercise found that benefits mostly showed up when the carbohydrate dose was too low to begin with (McLellan, Pasiakos and Lieberman, 2014). For a marathon or anything under about four hours, get carbohydrate and fluid right and don’t worry about protein on the course.

So why do ultrarunners eat protein?

Three practical reasons, none of them magic.

Flavour fatigue. By hour ten, another sweet gel can be hard to face. Savoury food with some protein in it, the soup, sandwiches and rice at trail aid stations, keeps people eating. An ultra runner who stops eating is in much more trouble than one who ate the “wrong” macronutrient.

Time on feet. In a 20 or 30 hour race you are covering most of a day’s meals on the move. Normal daily protein needs don’t switch off because you are wearing a bib.

Stomach comfort. Some runners find a little protein or fat makes a long stretch of pure sugar easier to tolerate. Others find the opposite. You only learn which one you are in training.

How much protein do endurance athletes need a day?

The International Society of Sports Nutrition puts most exercising people at 1.4 to 2.0 g per kg of body weight per day, spread across meals (Jäger et al., 2017). For a 65 kg trail runner that is roughly 90 to 130 g. Most of it should come from normal meals in the days around the race, not from what you eat on the course.

How to fit protein into an ultra plan

1. Carbohydrate first. Build your hourly carbohydrate and fluid plan before anything else.
2. Add protein from about hour four onwards, in small amounts, mostly through real food at aid stations.
3. Carry a backup for the stretches where aid station food is sweet-only or runs out, which happens more often at the back of the field.
4. Test it on your longest training runs, at race effort, in the heat.

For point 3, a pouch is easier to carry than a sandwich. QC Stamina is a race fuel pouch with 42 g of carbohydrate and 13 g of protein, mixed with 150 to 200 ml of water and taken one every 2 to 3 hours. That makes it a way to get protein in without giving up carbohydrate, which is the trade-off that matters here. Open it where you have water, like an aid station or drop bag. It contains milk, and if your race is under four hours you don’t need it.

Protein matters more once the race is over. We cover the post-race side in Recovery After a Marathon or Ultra.

References

1. Tarnopolsky M (2004). Protein requirements for endurance athletes. Nutrition, 20(7-8), 662-668.
2. Jäger R, Kerksick CM, Campbell BI, et al. (2017). International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition, 14, 20.
3. McLellan TM, Pasiakos SM, Lieberman HR (2014). Effects of protein in combination with carbohydrate supplements on acute or repeat endurance exercise performance: a systematic review. Sports Medicine, 44(4), 535-550.